MX2008010021A - Methods for treating unwanted weight loss or eating disorders by administering a trkb agonist - Google Patents

Abstract

This invention relates to methods for treating unwanted body weight loss (such as with cachexia and with aging), eating disorders (such as anorexia nervosa), or opioid-induced emesi by peripheral administration of a trkB agonist. The invention also relates to compositions and kit comprising a trkB agonist.

Description

PROCEDURES FOR DEALING WITH UNDESIED WEIGHT LOSS OR DISORDERS OF FOOD THROUGH ADMINISTRATION FROM AN AGONIST FOR TRKB FIELD OF THE INVENTION This invention relates to the use of an agonist for trkB in the treatment and / or prevention of unwanted weight loss, eating disorders, or opioid-induced emesis.

BACKGROUND OF THE INVENTION Neurotrophins are a family of small, homodimeric proteins that play a crucial role in the development and maintenance of the nervous system. Members of the neurotrophin family include nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), neurotrophin-4/5 (NT - 4/5 ), neurotrophin-6 (NT-6), and neurotrophin-7 (NT-7). Neurotrophins, similar to other polypeptide growth factors, affect their target cells through interactions with cell surface receptors. According to current knowledge, two classes of transmembrane glycoproteins act as receptors for neurotrophins. Neurons that respond to neurotrophins possess a common reduced molecular weight (65-80 kDa), low affinity receptor (LNGFR), also known as p75NTR or p75, which binds to NGF, BDNF, NT-3 and NT-4/5 with a KD of 2x10"9 M; and high-molecular-weight receptors (130-150 kDa), of high affinity (KD in the environment of 10 ~ 11 M), which are members of the trk family of receptor tyrosine kinases. of Trk receptors are trkA, trkB and trkC. Both BDNF and NT-4/5 bind to the trkB and p75NTR receptors with a similar affinity, however, mice with mutations in NT-4/5 and BDNF show phenotypes that In contrast, while NT-4/5"'" mice are viable and fertile and exhibit only mild sensory deficiency, BDNF mice "die during the early postnatal stages with severe neuronal deficits and behavioral symptoms. Fan and co., Nat. Neurosci. 3 (4): 350-7, 2000; Liu et al., Nature 375: 238-241, 1995; Conover et al., Nature 375: 235-238, 1995; Emfors et al., Nature 368: 147-150, 1994; Jones et al., Cell 76: 989-999, 1994. Several publications report that NT-4/5 and BDNF present different biological activities in vivo and suggest that different activities may derive in part from the differentiated activation of the trkB receptor and its downstream signaling routes through NT-4/5 and BDNF. Fan and co., Nat. Neurosci. 3 (4): 350-7, 2000; Minichiello and cois., Neuron. 21: 335-45, 1998; Wirth et al., Development. 130 (23): 5827-38, 2003; López et al., Program number 38.6, Summary of 2003, Society for Neuroscience.

Both BDNF and NT-4/5 have been shown to have blood glucose and blood lipid control activity and anti-obesity activity in models of animals with type II diabetes, such as C57 db / db mice . U.S. Patent No. 6,391, 312; Itakura et al., Metabolism 49: 29-33 (2000); U.S. Patent Application No. 2005/0209148; WO 2005/082401. It has also been shown that BDNF has anti-obesity activity and activity in the improvement of leptin resistance in mice fed a high-fat diet. U.S. Patent Application Publication No. 2003/0036512. Kernie et al. Reported that BDNF or NT-4/5 could transiently reverse feeding behavior and obesity in mice without heterozygous BDNF in which the expression of the BDNF gene was reduced. Kemie et al., EMBO J. 19 (6): 1290-300, 2000. It has been reported that a de novo antisense mutation of the Y722C substitution in human trkB produces deficient phosphorylation of MAP kinase receptors and signaling, and This mutation seems to cause a special human syndrome of obesity due to hyperphagia. Yeo et al., Nat. Neurosci., 7: 1 187-1 189 (2004). The circulating levels of BDNF have been studied in people with obesity and in patients with anorexia nervosa. Monteleone and cois. Psychosomatic Medicine 66: 744-748, 2004; Nakazato et al., Biol. Psychiatry 54: 485-490, 2003. Contrary to the prediction based on the findings that deficiencies in BDNF production in mice have been associated with increased food intake, lower expenditure of energy and weight gain, BDNF is significantly reduced in patients with anorexia nervosa and significantly increased in obese subjects compared to non-obese healthy controls. It has been hypothesized that in anorexia nervosa, the reduction of BDNF, by promoting food intake, attempts to compensate for the altered behaviors of patients that cause a negative balance; and in obesity, increased levels of BDNF may represent an adaptive mechanism to compensate for the condition of positive energy imbalance by stimulating energy expenditure and decreasing food intake. Monteleone et al., Psychosomatic Medicine 66: 74-748, 2004. All publications, patents and patent applications cited herein are hereby incorporated by reference in their entirety for all purposes with the same scope as if it is specifically and individually indicated that each publication, patent or patent application is incorporated by reference.

BRIEF SUMMARY OF THE INVENTION The present invention provides methods for increasing body weight and / or food intake by the peripheral administration of an agonist for trkB, which includes a selective agonist for trkB. These procedures can be used to treat or prevent unwanted weight loss (such as from cachexia or from aging), eating disorders (such as anorexia nervosa), and opioid-induced emesis. In one aspect, the invention provides methods for increasing body weight in a primate which comprises peripherally administering to the primate an effective amount of a trkB agonist. In another aspect, the invention provides methods for increasing food intake of a primate which comprises peripherally administering to the primate an effective amount of a trkB agonist. In another aspect, the invention provides methods for treating or preventing cachexia in a primate which comprises peripherally administering to the primate an effective amount of a trkB agonist. In another aspect, the invention provides methods for improving, reducing the incidence or delaying the development or progression of cachexia in a primate comprising peripherally administering to the primate an effective amount of a trkB agonist. In another aspect, the invention provides methods for treating unwanted weight loss in a pnmate comprising peripherally administering to the primate an effective amount of a trkB agonist. In another aspect the invention provides methods for improving, reducing the incidence or delaying the development or progression of unwanted weight loss in a primate comprising peripherally administering to the primate an effective amount of a agonist for trkB. In another aspect, the invention provides methods for treating or preventing anorexia nervosa in a primate comprising administering peripherally to the primate an effective amount of a trkB agonist. In another aspect, the invention provides methods for improving, reducing the incidence or delaying the development or progression of anorexia nervosa in a primate comprising peripherally administering to the primate an effective amount of a trkB agonist. In another aspect, the invention provides methods for treating or preventing opioid-induced emesis in an individual comprising peripherally administering to the individual an effective amount of a trkB agonist. In another aspect, the invention provides methods for improving, reducing the incidence or delaying the development or progression of opioid-induced emesis in an individual comprising administering peripherally to the individual an effective amount of an agonist for trkB. The agonist for trkB is administered peripherally. For example, the agonist for trkB can be administered by one of the following routes: intravenous, intraperitoneal, intramuscular, subcutaneous, parenteral, inhalation, intraarterial, intracardiac, intraventricular and transdermal. In some modalities, the individual is a primate. In some modalities, the primate is a human being. The agonist for trkB that can be used for the methods described herein, includes, but is not limited to, BDNF polypeptide, NT-4/5 polypeptide, and antibodies against agonists for trkB. In some embodiments, the agonist for trkB is human NT-4/5. In some embodiments, the agonist for trkB is human BDNF. In other embodiments, the agonist for trkB is an antibody against agonist for trkB, which includes an antibody against agonist for trkB that is selective for trkB. In some embodiments, the antibody against trkB is human or humanized. In another aspect, the invention provides pharmaceutical compositions comprising an effective amount of an agonist for trkB, including a selective agonist for trkB and a pharmaceutically acceptable excipient. The pharmaceutical compositions can be used to treat or prevent any of the diseases described herein. In another aspect, the invention provides kits comprising an agonist for trkB for use in any of the methods described herein. In some embodiments, the kits comprise a package, a composition comprising an effective amount of an agonist for trkB, combined with a pharmaceutically acceptable excipient, and instructions for using the composition in any of the methods described herein. In another aspect, the invention also provides methods for generating an agonist monoclonal antibody that specifically binds and activates a receptor, comprising the steps of: (a) immunizing a host mammal with an immunogenic molecule that it comprises an extracellular domain of the receptor by injecting the immunogenic molecule into the mammal at least twice in about 15 days. The methods may further comprise the steps of fusing lymphoid cells of the immunized mammal with an immortalized cell line producing hybridomas secreting monoclonal antibodies; cultivate hybridomas under the conditions that allow the secretion of monoclonal antibodies; and selecting a hybridoma that secretes a monoclonal antibody that binds and activates the receptor. In some modalities; The receiver is a receiver that requires dimerization for its activation. I 0 BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a graph showing the effect of daily infusion of NT-4/5 on body weight in obese female baboons. The X axis corresponds to the days in which the body weight was measured and the Y axis corresponds to the body weight measured in terms of percentage of the initial (body weight before starting any treatment). A two-way ANOVA was used to compare the group treated with NT-4/5 and the vehicle group. The data indicate that the body weight of the group treated with NT-4/5 was 0 significantly different from the group treated with vehicle (F = 50.71, P <0.0001). Bonferroni post hoc analyzes showed a significant difference between pairs of the group treated with NT-4/5 (black triangles) with the group treated with vehicle (white squares). * indicates P < 0.05; ** indicates P < 0.01; and *** indicates P < 0.001 as indicated in the graph. Figure 2 is a graph showing the effect of daily infusion of NT-4/5 on food intake in obese female baboons. The X axis corresponds to the days in which the food intake was measured and the Y axis corresponds to the number of biscuits ingested by each baboon per day. A two-way ANOYA was used to compare the group treated with NT-4/5 with the vehicle-treated group. The data indicate that the food intake of the group treated with NT-4/5 was significantly different from the group treated with vehicle (F = 262.5, P < 0.0001). The post hoc Bonferroni analyzes showed a significant difference between pairs of the group treated with NT-4/5 (black triangles) with the group treated with vehicle (white squares). The continuous black bar of the graph indicates the period during which the paired comparison returned. a P < 0.05 or lower. Figure 3 is a graph showing the effect of the infusion of NT-4/5 twice a week on body weight in obese female baboons. The X axis corresponds to the days in which the body weight was measured and the Y axis corresponds to the body weight measured in terms of percentage of the initial (body weight before no treatment). A two-way ANOVA was used to compare the group treated with NT-4/5 with the vehicle-treated group. The data indicated that the body weight of the group treated with NT-4/5 is significantly different from the group treated with vehicle (F = 34.81, P <; 0.0001). The post hoc Bonferroni analyzes showed a significant difference between pairs of the group treated with NT-4/5 (black triangles) with the group treated with vehicle (white squares). * indicates P < 0.05; and ** indicates P < 0.01. Figure 4 is a graph showing the effect of NT-4/5 infusion twice a week on food intake in obese female baboons. The X axis corresponds to the days in which the food intake was measured and the Y axis corresponds to the number of biscuits ingested per baboon per day. Figure 5 is a graph showing the effect of the daily NT-4/5 infusion and the pegylated weekly infusion of NT-4/5 on the body weight of thin macaques. The X axis corresponds to the days in which the body weight was measured and the Y axis corresponds to the body weight measured in terms of percentage of the initial (body weight before no treatment). A two-way ANOVA was used to compare the group treated with NT-4/5 or with pegylated NT-4/5 (PEG-NT-4/5) with the vehicle-treated group. The data indicated that the body weight of the group treated with NT-4/5 but not the group treated with pegylated NT-415, was significantly different from the group treated with vehicle (F = 54.98, P < 0.0001). Bonferroni post hoc analyzes showed a significant difference between pairs of the group treated with NT-4/5 (triangles) with the group treated with vehicle (squares) but not between the group treated with pegylated NT-415 (inverted triangles) and the group treated with vehicle. *** indicates P < 0.001 as indicated in the graph. Figure 6 is a graph showing the effect of the daily NT-4/5 infusion and the pegylated weekly infusion of NT-4/5 on the intake of food from thin macaques. The X axis corresponds to the days in which the food intake was measured and the Y axis corresponds to the number of biscuits ingested per monkey per day. A two-way ANOVA was used to compare the group treated with NT-4/5 or with pegylated NT-4/5 (PEG-NT-4/5) with the vehicle-treated group. The data indicated that the body weight of the group treated with NT-4/5 but not the group treated with pegylated NT-415, was significantly different from the group treated with vehicle (F = 33.82, P <0.0001). The post hoc Bonferroni analyzes showed a significant difference between pairs of the group treated with NT-4/5 (triangles) with the vehicle-treated group (squares) on days 15, 16, 17, 19, 22, 23, 25, and 50, but not a significant paired difference between the pegylated NT-4/5 group (inverted triangles) and the vehicle treated group. Figure 7 is a graph showing the effect of daily subcutaneous injection with NT-4/5 and daily with pegylated NT-4/5 on the body weight of thin macaques. The X axis corresponds to the days in which the body weight was measured and the Y axis corresponds to the body weight measured in terms of percentage of the initial (body weight before no treatment). A two-way ANOVA was used to compare the group treated with NT-4/5 or with pegylated NT-4/5 (PEG-NT-4/5) with the vehicle-treated group. The data indicated that body weight of the group treated with NT-4/5 was significantly different from the group treated with vehicle (F = 19.10, P <0.0001). The Bonferroni post hoc analyzes showed a significant difference between pairs of the group treated with NT-4/5 (triangles) with the group treated with vehicle (squares), and between the group of NT-4/5 pegylated (inverted triangles) and the group treated with vehicle. *** indicates P < 0.001; and ** indicates P < 0.01. Figure 8 is a graph showing the effect of a single injection of NT-4/5 on morphine-induced emesis in ferrets. The X axis corresponds to the type of drug injected; and the Y axis corresponds to the number of arches and vomits during a period of 60 minutes after the injection. A one-way ANOVA was used with a post-Dunnett's analysis for statistical analysis. The values of P are indicated in the graph. Figure 9A and Figure 9B show the induction of C-Fos in ferret rombencéfalo by NT-4/5. Figure 9A shows the number of nuclei that are stained by an antibody against c-Fos in the postrema area. Figure 9B shows the number of nuclei that are stained by an antibody against c-Fos in the dorsal vagus nucleus. Figure 10 shows the level of tyrosine phosphorylation for trkB in a KIRA assay by various antibodies against trkB (36D1, 38B8, 37D12, 19H8 (1), 1 F8, 2388, 18H6) compared to human NT-4/5. Figure 11 shows a graph of the survival of nodal neurons supported by various antibodies against agonists for trkB. The X axis represents the different concentrations of the antibodies against trkB added to the culture of embryonic nodule neurons on day 15 (E1 5) obtained from Swiss Webster mice. The Y axis represents the number of neurons at 48 hours after plating. Each point is an average of four determinations and the error bars show the variance between that average of a standard deviation. The data indicate that some of the antibodies against trkB analyzed can support the survival of nodal neurons and that the 50% effective concentration (EC50) of these antibodies under these culture conditions range from less than 0.1 to more than 10 pM (See Table 1). Figure 12A and Figure 12B are graphs showing the effect of intracranial injections of antibodies against agonists for trkB on body weight (Figure 12A) and food intake (Figure 128) in mice. Antibodies and NT-4/5 were injected on day 0. Body weight and food intake were measured daily until day 5. ** indicates P < 0.001 compared to control murine IgG; ** Indicates P < 0.01 compared with murine control IgG; and * indicates P < 0.05 compared to murine control IgG. Figure 13A and Figure 13B are graphs showing the effect of peripheral intravenous injections of antibody against agonist for trkB on body weight (Figure 13A) and food intake (Figure 13B) on macaques. The antibodies were injected on day 1. Body weight was monitored weekly and food intake was monitored daily. *** indicates P > 0.001 compared to a control vehicle; ** indicates P > 0.01 compared to a control vehicle; and '* indicates P > 0.05 compared to a control vehicle.

DETAILED DESCRIPTION OF THE INVENTION The present invention provides methods for treating or preventing unwanted weight loss (such as that associated with cachexia or aging), eating disorders (such as anorexia nervosa), and opioid-induced emesis comprising administering an agonist for trkB to a individual or a subject.

I. General Techniques The practice of the present invention will employ, unless otherwise indicated, conventional techniques of molecular biology (including recombinant techniques), microbiology, cell biology, biochemistry and immunology, which are within the scope of the art. . These techniques are fully explained in the literature, as such: Molecular Cloning: A Laboratory Manual, second edition (Sambrook, et al., 1989) Cold Spring Harbor Press; Oligonucleotide Synthesis (M.J. Gait, editor, 1984); Methods in Molecular Biology, Humana Press; Cell Biology: A Laboratory Notebook (J.E. Cellis, editor, 1998) Academic Press; Animal Cell Culture (R. Freshney, editor, 1987); Introduction to Cell and Tissue Culture (J.P. Mather and P.E. Roberts, 1998) Plenum Press; Cell and Tissue Culture: Laboratory Procedures (A. Doile, J.B. Griffiths, and D.G. Newell, eds., 1993-8) J. Wiley and Sons; Methods in Enzymology (Academic Press, Inc.); Handbook of Experimental Immunology (D.M. Weir and C.C. Blackwell, editors); Gene Transfer Vectors for Mammalian Cells (J.M. Miller and M.P. Calos, editors, 1987); Current Protocols In Molecular Biology (F.M. Ausubel, et al., Editors, 1987); PCR: The Polymerase Chain Reaction (Mullis, et al., Editors, 1994); Current Protocols in Immunology (J.E. coligan et al., Editors, 1991); Short Protocols in Molecular Biology (Wiley and Sons, 1999); Immunobiology (C.A. Janeway and P. Travers, 1997); Antibodies (P. Finch, 1997); Antibodies: a practical approach (D. Catty., Editor, IRL Press, 1988-1989); Monoclonal Antibodies: a practical approach (P. Shepherd and C. Dean, editors, Oxford University Press, 2000); Using Antibodies: a laboratory manual (E. Harlow and D. Lane (Cold Spring Harbor Laboratory Press, 1999), The Antibodies (M. Zanetti and J.D, Capra, editors, Harwood Academy Publishers, 1995).

II. Definitions As used herein, "treatment" is a strategy for obtaining beneficial or desired clinical results. For the purposes of this invention, beneficial or desired clinical outcomes include, but without limitation, one or more of the following: improve, decrease severity, relieve one or more symptoms associated with a disease. For example, for the treatment of cachexia and / or unwanted weight loss, beneficial or desired clinical results include, but are not limited to, decreasing the severity and / or alleviating one or more of any of the following: weight loss, lipolisis, loss of muscle and visceral protein, anorexia (ie, loss of appetite), reduced food intake / calories, nausea chronic, fatigue and weakness. For the treatment of anorexia nervosa, beneficial or desired clinical results include, but are not limited to, one or more of any of the following: improvement of appetite, attenuation of resentment to food, weight gain, maintenance of normal nutritional status, hydration and electrolyte balance, maintaining body weight for age and height, reducing the frequency and duration of hospitalization, and reducing the risk of death. For the treatment of opioid-induced emesis, beneficial or desired clinical outcomes include, but are not limited to, reducing the severity and / or shortening the duration of nausea and / or vomiting, thus allowing the full clinical benefits of induced pain reduction. for opioids. "Improving" a disease or one or more symptoms of the disease means reducing or improving one or more symptoms associated with the disease related to the non-administration of an agonist for trkB. "Improve" also includes shortening or reducing the duration of a symptom. "Reducing the incidence" of a disease means either reducing severity (which may include reducing the need and / or quantity (eg, exposure) of other drugs and / or treatments generally used for this condition), duration , and / or frequency (which includes, for example, delaying or increasing the time until the next episodic attack in an individual). As understood by those skilled in the art, individuals may vary in their response to treatment, and, therefore, for example, a procedure of reducing the incidence of a disease in an individual reflects administering the agonist for trkB based on a reasonable expectation that such administration may likely cause such a reduction in incidence in that particular individual. As used herein, "delaying" the development of a disease means deferring, slowing down, slowing down, delaying, stabilizing and / or postponing the progression of the disease. This delay can be of varying amounts of time, depending on the history of the disease and / or the individuals being treated. As is clear to a person skilled in the art, a sufficient or significant delay may, in fact, comprise prevention, because the individual does not develop the disease (e.g., cachexia, anorexia nervosa, and opioid-induced emesis). A procedure that "delays" the development of the symptom is a procedure that reduces the likelihood of developing the symptom in a given timeframe and / or reduces the duration of the symptoms in a given timeframe, compared to not using the procedure. These comparisons are usually based on clinical studies, using a statistically significant number of subjects. "Development" or "progression" of a disease means initial manifestations and / or subsequent progression of the disorder. The development of a disease can be detectable and evaluated using standard clinical techniques well known in the art. However, the development also refers to a progression that may not be detectable. For the purposes of this invention, the development or progression refers to the biological course of the symptom. "Development" includes appearance, reappearance and initiation. As used herein, "onset" or "onset" of a disease includes first onset and / or reappearance. As used herein, an "effective dose" or "effective amount" of drug, compound, or pharmaceutical composition is an amount sufficient to produce beneficial or desired results. For prophylactic use, the beneficial or desired results include results such as eliminating or reducing the risk, decreasing the severity or delaying the onset of the disease, which includes the biochemical, histological and / or behavioral symptoms of the disease, its complications and intermediate pathological phenotypes that occur during the development of the disease. For therapeutic use, beneficial or desired results include clinical outcomes such as reducing the intensity, duration, or frequency of disease attack, and decreasing one or more symptoms produced by the disease (biochemical, histological and / or behavioral), that include their complications and intermediate pathological phenotypes that occur during the development of the disease, increase the quality of life of those suffering from the disease, decrease the dose of other medications necessary to treat the disease, enhance the effect of another medication, and / or delay the progression of patients' disease. An effective dose can be administered in one or more administrations. For the purposes of this invention, an effective dose of drug, compound, or pharmaceutical composition is a sufficient amount to achieve a prophylactic or therapeutic treatment either directly or indirectly. As understood in the clinical context, an effective dose of a drug, compound, or pharmaceutical composition may not be achieved in conjunction with another drug, compound, or pharmaceutical composition. Thus, an "effective dose" can be considered in the context of administering one or more therapeutic agents, and a single agent can be considered to be administered in an effective amount if, together with another or other agents, a desired result can be achieved or achieved. . An "individual" or a "subject" is a mammal, more preferably, a human being. Mammals also include, but are not limited to, farm animals, sports animals, primates (including humans), horses, dogs, cats, mice and rats. An "agonist for trkB" refers to an agent that is capable of binding and activating a trkB receptor and / or downstream path (s) mediated by the signaling function for trkB. For example, the agonist can bind to the extracellular domain of a trkB receptor and thus cause the dimerization of the receptor, causing the activation of the intracellular catalytic kinase domain. Accordingly, this may cause stimulation of growth and / or differentiation of the cells expressing the receptor in vitro and / or in vivo. In some embodiments, an agonist for trkB binds to trkB and activates a biological activity for trkB. "Biological activity", when used in conjunction with the agonist for trkB of the present invention, generally refers to having the ability to join and activate the trkB receiver and / or a downstream path mediated by the signaling function for trkB. As used herein, "biological activity" encompasses one or more effector functions in common with those induced by the action of NT-4/5 and / or BDNF, the native ligand for trkB, in a cell expressing trkB . Without limitation, biological activities include one or more of any of the following: ability to bind and activate trkB; ability to promote trkB receptor dimerization; the ability to promote the development, survival, function, maintenance and / or regeneration of cells (including damaged cells), in particular neurons in vitro or in vivo, including peripheral neurons (sympathetic, sensory, motor and enteric) and central neurons (brain and spinal cord), non-neuronal cells, for example peripheral blood leukocytes, endothelial cells and vascular smooth muscle cells. A particular preferred biological activity is the ability to increase body weight and / or food intake in a primate when administered peripherally, to treat (including prevention) one or more symptoms of cachexia and anorexia nervosa in a primate, and / or treating (including prevention) one or more symptoms of opioid-induced emesis in a mammal. An "antibody to an agonist for trkB" (interchangeably called "antibody to an agonist for trkB") refers to an antibody that is capable of binding and activating a trkB receptor and / or pathway (s) downstream mediated by the signaling function for trkB. For example, him antibody against an agonist can bind to the extracellular domain of a trkB receptor and thus cause dimerization of the receptor, causing activation of the kinase domain. Consequently, this may cause the stimulation of the growth and / or differentiation of the cells expressing the receptor in vitro and / or in vivo. In some embodiments, an antibody against an agonist for trkB binds to trkB and activates a biological activity for trkB. As used herein, "peripheral administration" or "peripherally administered" refers to introducing an agent into a subject outside the central nervous system (CNS) or the blood-brain barrier (BBB). Peripheral administration encompasses any route of administration other than direct administration to the spinal cord or the brain. Peripheral administration can be local or systemic. An "antibody" is an immunoglobulin molecule capable of specifically binding to a target, such as a carbohydrate, polynucleotide, lipid, polypeptide, etc., through at least one antigen recognition site, located in the variable region of the immunoglobulin molecule. As used herein, the term encompasses not only intact polyclonal or monoclonal antibodies, but also their fragments (such as Fab, Fab ', F (ab') 2, Fv), single-stranded (ScFv), their mutants , fusion proteins comprising a portion of antibody (such as domain antibodies), and any other modified configuration of the immunoglobulin molecule comprising an antigen recognition site. An antibody includes an antibody of any class, such as IgG, IgA, or IgM (or a subclass thereof), and the antibody does not have to be of any particular kind. Depending on the amino acid sequence of the constant domain antibody of their heavy chains, the immunoglobulins can be assigned to different classes. There are five main classes of immunoglobulins; IgA, IgD, IgE, IgG, and IgM, and several of these can further be divided into subclasses (isotypes), for example, IgG 1, IgG2, IgG3, IgG4, IgA1 and IgA2. The constant domains of the heavy chain that correspond to the different classes of immunoglobulins are called alpha, delta, epsilon, gamma, and mu, respectively. The subunit structures and the three-dimensional configurations of the different classes of immunoglobulins are well known. As used herein, "monoclonal antibody" refers to an antibody obtained from a population of substantially homogeneous antibodies, ie, the individual antibodies comprising the population are identical with the exception of possible natural mutations that can be present in minority amounts. Monoclonal antibodies are very specific, targeting a single antigenic site. In addition, unlike with polyclonal antibody preparations, which usually include different antibodies directed against different determinants (epitopes), each monoclonal antibody is directed against a single determinant of the antigen. The "monoclonal" modifier indicates the character of the antibody that is obtained from a substantially homogeneous population of antibodies, and is not to be construed as requiring the production of the antibody by any particular procedure. For example, the monoclonal antibodies to be used according to the present invention can be prepared by the hybridoma method first described by Kohler and Milstein, 1975, Nature, 256: 495, or they can be prepared by DNA recombination methods such as which are described in U.S. Patent No. 4,816,567. Monoclonal antibodies can also be isolated from phage collections using the techniques described in McCafferty et al., 1990. Nature, 348: 552-554, for example. As used herein, "humanized" antibodies refer to non-human (e.g., murine) antibody forms that are specific chimeric immunoglobulins, immunoglobulin chains, or fragments thereof (such as Fv, Fab, Fab ', F). (ab ') 2 or other subsequences of antibodies that bind to antigens) containing minimal sequences derived from non-human immunoglobulin. For the most part, the humanized antibodies are human immunoglobulins (receptor antibody) in which the residues of a receptor complementarity determining region (CDR) are replaced by residues of a CDR of a non-human species (donor antibody) such as a mouse, rat or rabbit having the desired specificity, affinity and biological activity. In some cases, the remains of the structural region (FR) Fv of human immunoglobulin are replaced by non-human residues corresponding. In addition, the humanized antibody may comprise residues which are found neither in the recipient antibody nor in the imported CDR sequences nor in the structural sequences, but are included to refine and further optimize the performance of the antibody. In general, the humanized antibody will substantially comprise all of at least one, and usually two variable domains, in which all or substantially all of the CDR regions correspond to those of a non-human immunoglobulin and all or substantially all of the FR regions are those of a consensus region of human immunoglobulin. The humanized antibody optimally will also comprise at least a portion of a constant region or domain (Fe) of immunoglobulin, usually that of a human immunoglobulin. The antibodies can have modified Fe regions as described in WO 99/58672. Other forms of humanized antibodies have one or more CDRs (one, two, three, four, five, six) that are altered with respect to the original antibody, which are also referred to as one or more CDRs "derived from" one or more CDRs of the original antibody. As used herein, "human antibody" means an antibody having an amino acid sequence corresponding to that of an antibody produced by a human and / or has been prepared using any of the techniques for preparing known human antibodies. in the art or described herein. This definition of a human antibody includes antibodies that comprise minus a human heavy chain polypeptide or at least one light chain polypeptide. One such example is an antibody comprising murine light chain and human heavy chain polypeptides. Human antibodies can be produced using various techniques known in the art. In one embodiment, the human antibody is selected from a collection of bacteriophages, wherein said collection of bacteriophages expresses human antibodies (Vaughan et al., 1996, Nature Biotechnology, 1 4: 309-314; Sheets et al., 1998, PNAS, (USA) 95: 6157-6162; Hoogenboom and Winter, 1991, J. Mol. Biol., 227: 381; Marks et al., 1991, J. Mol. Biol. 222: 581). Human antibodies can also be prepared by inducing immunoglobulin loci in transgenic animals, for example, mice in which the endogenous immunoglobulin genes have been partially or completely inactivated. This strategy is described in United States Patent Nos. 5,545,807; 5,545,806; 5,569,825: 5,625, 126; 5,633,425; and 5,661, 016. Alternatively, the human antibody can be prepared by immortalizing human B lymphocytes that produce an antibody directed against a target antigen (said B lymphocytes can be recovered from an individual or they can have been immunized in vitro). See, for example, Cote et al., Monoclonal Antibodies and Cancer Therapy, Alan R. Liss, p. 77 (1988): Boemer and cois. 1991, J. Immunol., 147 (1): 86-95; and U.S. Patent No. 5,750,373. A variable region of an antibody refers to the variable region of the light chain of the antibody or the variable region of the chain heavy of the antibody, either alone or combined. The variable regions of the heavy and light chain are each constituted by four structural regions (FR) connected by three complementarity determining regions (CDR) also known as hypervariable regions. The CDRs of each chain are kept close together by the FRs and, with the CDRs of the other chain, contribute to the formation of the antigen binding site of the antibodies. There are at least two techniques for determining CDRs: (1) a strategy based on the variability of sequences between species (ie, Kabat et al., Sequences of Proteins of Immunological Interest, (5th edition, 1991, National Institutes of Health, Bethesda MD), and (2) a strategy based on crystallographic studies of complexes between antigen and antibody (Al-lazikani et al (1997) J. Molec. Biol. 273: 927-948)). As used herein, a CDR can refer to CDRs defined by either strategy or a combination of both strategies. A "constant region" of an antibody refers to the constant region of the light chain of the antibody or the constant region of the heavy chain of the antibody, either alone or in combination. An epitope that "binds preferentially" or "binds specifically" (are used interchangeably herein) to an antibody or a polypeptide is a term well understood in the art, and methods for determining said specific or preferential binding are also notorious in the art. A molecule is said to shows "specific binding" or "preferential binding" if it reacts or associates more frequently, more rapidly, with longer duration and / or with greater affinity with a particular cell or substance than with cells or alternative substances. An antibody binds "specifically" or binds "preferentially" or binds "selectively" to a target if it binds with greater affinity, avidity, more easily and / or with longer duration than it binds to other substances. For example, an antibody that binds specifically or preferentially to an epitope for trkB is an antibody that binds to this epitope with greater affinity, avidity, more easily and / or with longer duration than it binds to other epitopes for trkB or different epitopes for trkB. It is also understood when reading this definition that, for example, an antibody (or moiety or epitope) that binds specifically or preferentially to a first target may or may not bind specifically or preferentially to a second target. Therefore, "specific" binding or "preferential" binding or "selective" binding of an antibody to trkB does not necessarily (but may include) exclusive binding. Generally, but not necessarily, when reference is made to selective binding to trkB, preferential binding is meant (for example, binding with an Cl50 at a concentration of at least 3.5, or, preferably, at least 10 times or 100 times lower for trkB than to other receivers). The term "Fe region" is used to define a region of the C-terminus of an immunoglobulin heavy chain. The "Fe region" may be a region of native Fe sequence or a variable Fe region.

Limits of the Fe region of an immunoglobulin heavy chain may vary, the heavy chain region of human IgG is usually defined as a stretch from an amino acid residue of the Cys226 position, or from Pro230, to its carboxyl terminus. The numbering of the remains of the Fe region is that of the Kabat EU index. Sequences of Proteins of Immunological Interest, (5th edition, 1991, National Institutes of Health, Bethesda MD, 1991. The Fe region of an immunoglobulin generally comprises two constant domains CH2 and CH3, as used herein, "Fe "and" FcR "describe a receptor that binds to the Fe region of an antibody The FcR is a human FcR of native sequence In addition, a preferred FcR is one that binds to an IgG antibody (a gamma receptor) and includes recipients of the subclasses FCyRI, FCyRIl, FCYRI II and FCyRIV, which include allele variants and forms with alternative splices of these receptors.RTMRRI receptors include FCyRIIA (an "activating receptor") and FCyRIIB (an "inhibitory receptor"), having similar amino acid sequences that differ mainly in their cytoplasmic domains FcRs are reviewed in Ravetch and Kinet, 1991, Ann. Rev. Immunol., 9: 457-92; Capely cois., 1004. Immunomethods, 4: 25- 34; de Haas et al., 1995, J Lab. Clin. Med., 126: 330-41; Nimmerjahn and cois. 2005, Immunity 23: 2-4. The "FcR" also include the neonatal receptor, FcRn, which is responsible for the transfer of the maternal IgGs to the fetus (Guyer et al., 1976, J. Immunol., 1 1 7: 587; and Kim et al., 1994). , J. Immunol., 24: 249).

"Complement-dependent cytotoxicity" and "CDC" refers to the lysis of a target in the presence of complement. The complement activation pathway is initiated by binding the first component of the complement system (C1 q) to a molecule (e.g., an antibody) that complexes with a cognate antigen. To evaluate complement activation, a CDC assay can be performed, for example, as described in Gazzano-Santoro et al., J. Immunol. Methods 202: 163 (1996). A "functional Fe region" has at least one effector function of a native Fe sequence. Exemplary "effector functions" include binding of C1 q; Complement-dependent cytotoxicity (CDC); Fe receptor binding; antibody-dependent cell-mediated cytotoxicity (ADCC); phagocytosis; down regulation of cell surface receptors (eg B lymphocyte receptor, BCR), etc. Said effector functions generally require combining the Fe region with a binding domain (e.g., an antibody variable domain) and can be evaluated using various assays known in the art to evaluate said effector functions of the antibodies. A "Fe region of native sequence" comprises an amino acid sequence identical to the amino acid sequence of a Fe region found in nature. A "variable Fe region" comprises an amino acid sequence that differs from a Fe region of native sequence by virtue of at least one modification of an amino acid but still maintains an effector function of the Fe region of the native sequence.

Preferably, the variable Fe region has at least one amino acid substitution compared to a Fe region of native sequence or to the Fe region of a parent polypeptide, for example from about one to about ten amino acid substitutions, and preferably from about one to about five amino acid substitutions of a Fe region of native sequence or of the Fe region of a parent polypeptide. The variable Fe region in the present document will preferably possess at least about 80% sequence identity with a native sequence Fe region and / or with a Fe region of a parent polypeptide, and most preferably at least about one sequence identity 90% with her, more preferably, a sequence identity of at least about 95%, at least about 96%, at least about 97%, at least about 98%, at least about 99% with it. As used herein, "antibody-dependent cell-mediated cytotoxicity" and "ADCC" refer to a cell-mediated reaction in which non-specific cytotoxic cells expressing Fe (FcR) receptors (e.g., natural killer cells) NK), neutrophils, and macrophages) recognize the bound antibody in a target cell and subsequently cause the lysis of the target cell. The ADCC activity of a molecule of interest can be evaluated using an in vitro ADCC assay, such as that described in U.S. Patent No. 5,500,362 or 5,821, 337. Effector cells useful for such assays they include peripheral blood mononuclear cells (PBMC) and NK cells. Alternatively, or in addition, the ADCC activity of the molecule of interest can be evaluated in vivo, for example, in an animal model such as those described in Clynes et al., 1998, PNAS (USA), 95: 652 -656. As used herein, "pharmaceutically acceptable carrier" or "pharmaceutically acceptable excipient" includes any material that, when combined with an active ingredient, allows the ingredient to maintain its biological activity and does not react with the subject's immune system, Examples include, but are not limited to, any of the standard pharmaceutical carriers such as phosphate buffered saline, water, emulsions such as oil / water emulsion, and various types of wetting agents. Preferred diluents for aerosol or parenteral administration are phosphate buffered saline or normal saline (0.9%). Compositions comprising such vehicles are formulated by conventional notorious methods (see, eg, Remington's Pharmaceutical Sciences, 18th edition, A. Gennaro, publisher, Mack Publishing Co., Easton, PA, 1990, and Remington, The Science and Practice of Pharmacy 20th edition, Mack Publishing, 2000). The terms "polypeptide", "oligopeptide", "peptide" and "protein" are used interchangeably herein to refer to polymers of amino acids of any length. The polymer can be linear or branched, it can comprise modified amino acids, and it can be interrupted by molecules other than amino acids. The terms also encompass an amino acid polymer that has been modified naturally or by intervention; for example, formation of disulfide bonds, glycosylation, lipidation, acetylation, phosphorylation or any other manipulation of modification, such as conjugation with a labeling component. Also included in the definition are, for example, polypeptides that contain one or more analogs of an amino acid (including, for example, non-natural amino acids, etc.), as well as other modifications known in the art. It is understood that, because the polypeptides of this invention are based on an antibody, the polypeptides may appear in the form of single chains or associated chains. "Polynucleotide", or "nucleic acid," as used interchangeably herein, refers to polymers of nucleotides of any length, and includes DNA and RNA. The nucleotides can be deoxyribonucleotides, ribonucleotides, modified nucleotides or bases, and / or their analogs, or any substrate that can be incorporated into a polymer by DNA or RNA polymerase. A polynucleotide can comprise modified nucleotides, such as methylated nucleotides and their analogues. If there is, the modification of the nucleotide structure can be done before or after the assembly of the polymer. The nucleotide sequence may be interrupted by components other than the nucleotides. A polynucleotide can be further modified after the polymerization, for example by conjugation with a component of marked. Other types of modifications include, for example, "caps", substitution of one or more of the natural nucleotides by an analog, internucleotide modifications such as, for example, those of uncharged bonds (eg, methylphosphonates, phosphonates, phosphotriesters, phosphoamidates). , carbamates, etc.) and with charged bonds (for example, phosphorothioates, phosphorodithioates, etc.), those containing outstanding residues, such as, for example, proteins (for example, nucleases, toxins, antibodies, signal peptides, ply -L-lysine, etc.), those that have intercalators (for example, acridine, psotalen, etc.), those that contain chelants (for example, metals, radioactive metals, boron, oxidative metals, etc.), those that contain renters, those having modified bonds (eg, anomeric alpha nucleic acids, etc.), as well as unmodified forms of the polynucleotide (s). In addition, any hydroxyl groups that are usually present in the sugars can be substituted, for example, by phosphonate groups, phosphate groups, groups protected by standard or activated protecting groups to prepare additional bonds to additional nucleotides, or they can be conjugated to solid supports. The OH of the 5 'and 3' ends may be phosphorylated or substituted with amines or organic cap group residues of 1 to 20 carbon atoms. Other hydroxyls can also be derived to standard protecting groups. The polynucleotides may also contain analogous forms of ribose or deoxyribose sugars which are generally known in the art, including, for example, 2'-O-methylene-, 2-O-allyl, 2'- fluoro- or 2'-azororibose, carbocyclic sugar analogues, D-anomeric sugars, epimeric sugars such as arabinose, xyloses or lixoses, pyranose sugars, furanose sugars, sedoheptuloses, acyclic analogues and abbasic nucleoside analogs such as methylhosoid . One or more phosphodiester linkages can be substituted by alternative linking groups. These alternative linking groups include, but are not limited to, embodiments in which the phosphate is replaced by P (0) S ("thioate") P (S) S ("dithioate"), (0) NR2 ("amidate") , P (0) R, P (0) OR ', CO or CH2 ("formacetal"), wherein each R or R' is independently H or substituted (1 -20 C) alkyl or unsubstituted which optionally contains a link ether (-0-), aryl, alkenyl, cycloalkyl, cycloalkenyl or aryryl. Not all the links of a polynucleotide have to be identical. The foregoing description applies to all polynucleotides referred to herein, including RNA and DNA. As used herein, "substantially pure" refers to a material that is at least 50% pure (ie, free of contaminants), more preferably, pure at least 90%, more preferably, pure at least 95%, more preferably, pure at least 98%, more preferably, at least 99% pure. A "host cell" includes a single cell or a cell culture that can be or has been a recipient of vector (s) for the incorporation of polynucleotide inserts. Host cells include the progeny of a single host cell and the progeny may not necessarily be completely identical (in morphology or in complement of genomic DNA) to the original progenitor cell due to a natural, accidental, or deliberate mutation. A host cell includes cells transfected in vivo with a polynucleotide (s) of this invention. As used herein, "vector" means a construct, which is capable of administering and preferably expressing one or more gene (s) or sequence (s) of interest in a host cell. Examples of vectors include, but are not limited to, viral vectors, naked DNA or RNA expression vectors, plasmids, cosmic or bacteriophage vectors, DNA or RNA expression vectors associated with cationic condensation agents, encapsulated DNA or RNA expression vectors. in liposomes and certain eukaryotic cells, such as producer cells. As used herein, "expression control sequence" means a nucleic acid sequence that directs the transcription of a nucleic acid. An expression control sequence may be a promoter, such as a constitutive or inducible promoter, or an enhancer. The expression control sequence is operably linked to the nucleic acid sequence to be transcribed. The term "Kon", as used herein, is intended to refer to the rate of association of an antibody to an antigen. The term "Koff", as used herein, is intended to refer to the rate constant of the dissociation of a Antibody complex antibody / antigen. "The term" KD ", as used herein, is intended to refer to the dissociation constant in the balance of the interaction between antibody and antigen interaction. in this document, the singular form "one", "one", and "the" include plural references unless otherwise indicated.

III. Methods of the Invention The present invention encompasses methods for increasing body weight and / or food intake by peripheral administration of a trkB agonist. These methods can be used to treat or prevent unwanted weight loss (such as cachexia) and eating disorders (such as anorexia nervosa) in primates, and opioid-induced emesis in mammals.; The method involves the peripheral administration of an effective amount of one more agonist for trkB to an individual in need (various indications and aspects are described herein). With respect to all the procedures described herein, when referring to agonists for trkB it also includes compositions comprising one or more of these agents. These compositions may further comprise suitable excipients, such as pharmaceutically acceptable excipients which include tampons, which are notorious in the art. The present invention can be used alone or in combination with other conventional treatment methods. Cachexia that can be treated and / or prevented by the procedures described herein may be caused and / or be associated with one or more of the following: chronic obstructive pulmonary disease (COPD), chronic kidney disease (CKD), failure Chronic heart disease (CCI), aging cancer and AIDS. In some embodiments, human patients who have treated cachexia or who have unwanted weight loss treated have a Body Mass Index (BMI, calculated in terms of body weight per height in square meters (kg / m2)) less than about any 25.0 kg / m2, 24.0 kg / m2, 23.0 kg / m2, 22.0 kg / m2, 21 .0 kg / m2, 20.0 kg / m2, 19.0 kg / m2, and 18.5 kg / m2. In some embodiments, human patients who have treated cachexia or who present unwanted weight loss treated have a daily food intake of less than about 90%, approximately 80%. about 70%, about 60%, about 50%, about 40%, about 30%, about 20%, or about 10% of the recommended normal daily intake level or premorbid level. In some embodiments, human patients presenting with anorexia nervosa treated by the methods described herein have a BMI less than any of approximately 18. 5 kg / m2, 1 7.5 kg / m2, and 16.5 kg / m2 In some embodiments, human patients who present with treated anorexia nervosa have a daily food intake of less than about 90%, about 80%, about 70%, about 60 %, approximately 50%, approximately 40%, approximately 30%, approximately 20%, or approximately 10% of the recommended normal daily intake level or premorbid level. The agonist for trkB is administered peripherally. It is understood that although the agent is administered peripherally, a small percentage of the agent can cross the blood-brain barrier and cause administration to the central nervous system depending on the properties of the agent. In some embodiments, less than any of about 1%, about 0.5%, about 25% and about 0.1% of the trkB agonist that is administered peripherally (eg, antibody against the agonist for trkB) is delivered to the CNS. The agonist for trkB can be administered to an individual by any suitable peripheral route. It should be obvious to a person skilled in the art that the examples described herein are not intended to be limiting but rather illustrative of the techniques available. Accordingly, in some embodiments, the agonist for trkB is administered to an individual according to known procedures, such as intravenous administration, by example, in a bolus form or by continuous infusion over a period of time, intramuscularly, intraperitoneally, subcutaneously, intrarticularly, sublingually, intrasynovially, by insufflation, orally, inhalation or topically. The administration can be systemic, for example, intravenous or localized administration. Commercially available nebulizers for liquid formulations, including jet nebulizers and ultrasonic nebulizers are useful for administration. The liquid formulations can be nebulized directly and the lyophilized powder can be nebulized upon reconstitution. Alternatively, the agonist for trkB can be given an aerosol form using a fluorocarbon formulation and a metered dose inhaler or inhaled in the form of a lyophilized and ground powder. An agonist for trkB can be administered by site-specific local administration techniques or directed outside the CNS or the blood-brain barrier. Examples of site-specific or targeted local administration techniques include various implantable depot sources of the agonist for trkB or local administration catheters, such as infusion catheters, an internal catheter or needle catheter, synthetic grafts, adventitious appositories, shunts and prostheses or other implantable devices, site specific vehicles, direct injection, or direct application. See, for example, PCT publication No. WO 00/5321 1 and United States Patent No. 5,981, 568. Various formulations of agonists for trkB can be used for administration. In some modalities, an agonist for trkB can administer pure. In other embodiments, an agonist for trkB and a pharmaceutically acceptable excipient is administered and can be in various formulations. Pharmaceutically acceptable excipients are well known in the art, and are relatively inert substances that facilitate the administration of a pharmacologically effective substance. For example, an excipient can give shape or consistency, or act as a diluent. Suitable excipients include, but are not limited to, stabilizing agents, wetting and emulsifying agents, salts for varying the osmolality, encapsulating agents, buffers and enhancers of skin penetration. The excipients as well as the formulations for parenteral and non-parenteral administration of drugs are described in Remington, The Science and Practice of Pharmacy, 20th edition, Mack Publishing, (2000). Generally, these agents are formulated for administration by injection (eg, intraperitoneally, intravenously, subcutaneously, intramuscularly, etc.), although other forms of administration (eg, oral, mucosal, transdermal, inhalation, etc.) may also be used. .). The particular dosage, ie, the dose, time and repetition will depend on the particular individual and clinical history of that individual, the particular disease (eg, cachexia, unwanted weight loss, anorexia nervosa, and emesis induced by opioids) to be treated and the agonist for particular trkB. Generally, any of the following doses of agonist for trkB (eg, NT-4/5, BDNF, and an antibody against agonist for trkB) can be used: a dose of at least one dose is administered approximately 50 mg / kg of body weight; at least about 20 mg / kg of body weight; at least about 10 mg / kg of body weight; at least about 5 mg / kg of body weight; at least about 3 mg / kg of body weight; at least about 2 mg / kg of body weight; at least about 1 mg / kg of body weight; at least about 750 pg / kg of body weight; at least about 500 pg / kg of body weight; at least about 250 pg / kg of body weight; at least about 100 pg / kg body weight; at least about 50 pg / kg of body weight; at least about 10 pg / kg of body weight; at least about 1 pg / kg of body weight or more. Empirical considerations, such as half-life, will generally help determine the dose. For repeated administrations in several days or longer, depending on the condition, treatment is maintained until the desired suppression of disease symptoms occurs or until sufficient therapeutic levels are achieved. For example, administration is contemplated one to five times a week. Other administration guidelines include a dosage of up to 1 time per day, 1 to 5 times a week or less frequently. In some embodiments, the agonist for trkB is administered approximately once a week, approximately 1 to 4 times per month. An intermittent administration schedule with tiered administrations separated by 2 days to 7 days or even 14 days can be used. In some modalities, treatment can be started with a daily dose and then changed to a weekly and even monthly administration. The progress of this treatment is easily controlled by conventional techniques and tests. In some individuals, more than one dose may be necessary. The frequency of administration can be determined and adjusted during the course of treatment. For example, the frequency of administration can be determined or adjusted based on the type and severity of the disease to be treated, regardless of whether the agent is administered for prevention or therapeutic purposes, prior treatment, patient's medical history and response. to the agent, and the judgment of the attending physician. Habitually, the doctor will administer an agonist for trkB until a dose is reached that achieves the desired result. In some cases, the use of sustained release formulations of agonist for trkB may be appropriate. Various formulations and devices are known in the art to achieve sustained release. For example, the agonist for trkB can be administered by a mechanical pump or embedded in a matrix bed for sustained or slow release. In one embodiment, the doses of an agonist for trkB can be determined empirically in individuals who have undergone one or more administrations. Increasing doses of an agonist for trkB are administered to individuals. To assess the efficacy of an agonist for trkB, markers of disease status can be controlled. It will be obvious to a person skilled in the art that the dose will vary depending on the individual, the stage of the disease (such as cachexia, opioid-induced anorexia nervosa and emesis), and the past and concurrent treatments that are being used. The administration of an agonist for trkB according to the method of the present invention can be continuous or intermittent, depending, for example, on the physiological state of the receptor, on whether the purpose of administration is therapeutic or prophylactic, and on other known factors by expert practitioners. Administration of an agonist for trkB may be essentially continuous for a selected period of time or may be in a series of spaced doses. Other suitable formulations include suitable administration forms known in the art including, but not limited to, vehicles such as liposomes. See, for example, Mahato et al. (1997) Pharm. Res. 14: 853-859. Liposomal preparations include, but are not limited to, cytofectins, multilamellar vesicles and unilamellar vesicles. The evaluation of the disease is performed using standard procedures known in the art, for example, by controlling the appropriate marker (s). For example, for cachexia, the following markers can be controlled: body weight, plasma albumin, body fat, lean body mass, fatigue, weakness and appetite. For anorexia nervosa, the following markers can be controlled: body weight, appetite and fear of gaining weight. For opioid-induced emesis, the following markers can be controlled: nausea, vomiting, Appetite, body weight, and other associated medical complications.

IV. Compositions and methods of preparing the compositions The methods of the invention use an agonist for trkB, which refers to any molecule that binds and activates the native trkB receptor and / or the downstream pathways mediated by the signaling function for trkB. The agonist for trkB includes any ligand native to a trkB receptor, such as NT-4/5 and BDNF. The agonist for trkB also includes a non-native ligand (e.g., polypeptides, compound derived from peptides, molecules derived from cyclic peptides or derived from molecules other than peptides) from a trkB receptor that binds and activates a native trkB receptor, mimicking thus a biological activity of a ligand native to the receptor. An example of non-native ligands of a trkB receptor is an antibody against an agonist for trkB. The agonists for trkB also include small molecules or peptidomimetics (for example, peptide mimetics of BDNF). See, for example, O'Leary et al., J. Biol. Chem. 278: 25738-44, 2003. In some embodiments, the small molecule trkB agonist does not significantly cross the blood-brain barrier when administered in a peripheral. An agonist for trkB should show one or more of any of the following characteristics: (a) bind to a trkB receiver; (b) joining a trkB receptor and activating the biological activity (s) for trkB and / or one or more downstream routes mediated by the signaling function (s) for trkB; (c) binding to a trkB receptor and increasing body weight and / or food intake in a primate when administered peripherally; (d) binding to a trkB receptor and treating, preventing, reversing or ameliorating one or more symptoms of cachexia or unwanted weight loss in a primate when administered peripherally; (e) binding to a trkB receptor and treating, preventing, reversing or ameliorating one or more symptoms of anorexia nervosa in a primate when administered peripherally; (f) binding to a trkB receptor and treating, preventing, reversing or ameliorating one or more symptoms of opioid-induced emesis in a mammal when administered, peripherally: (g) promoting dimerization and activation of the trkB receptor; and (h) increase neuronal survival dependent on the trkB receptor and / or neurite growth. In some embodiments, the agonist for trkB binds and activates the trkB receptor, but does not significantly or preferentially activate another or other trk receivers, such as trkA and / or trkC. The agonist for trkB may be in the form of a composition for use in any of the methods described herein. The composition that is used in the methods of the invention comprises an effective amount of an agonist for trkB. The composition may further comprise pharmaceutically acceptable carriers, excipients, or stabilizers (Remington, The Science and Practice of Pharmacy 20th edition (2000) Lippincott Williams and Wilkins, editor K. E. Hoover,), in the form of lyophilized formulations or aqueous solutions.

Suitable carriers, excipients or stabilizers are non-toxic to recipients at doses and concentrations, and may comprise buffers such as phosphate, citrate and other organic acids; antioxidants that include ascorbic acid and methionine; preservatives (such as octadecyldimethylbenzyl ammonium chloride, hexamethonium chloride, benzalkonium chloride, benzethonium chloride, phenol, butyl or benzyl alcohol, alkyl parabens such as methyl or propylparaben, catechol, resorcinol, cyclohexanol, 3-pentanol, and m-cresol); low molecular weight polypeptides (less than about 10 residues); proteins, such as serum albumin; gelatin, or immunoglobulins; hydrophilic polymers such as polyvinylpyrrolidone; amino acids such as glycine, glutamine, asparagine, histidine, arginine, or lysine; monosaccharides, disaccharides, and other carbohydrates including glucose, mannose, or dextrans; chelating agents such as EDTA; sugars such as sucrose, mannitol, trehalose or sorbitol; conjugated ions that form salts such as sodium; metal complexes (for example complexes of Zn and protein); and / or nonionic surfactants such as TWEEN ™, PLURONICS ™ or polyethylene glycol (PEG). The pharmaceutically acceptable excipients are further described herein. The agonists for trkB described herein can be formulated for sustained release. Suitable examples of sustained release preparations include semipermeable matrices of solid hydrophobic polymers containing agonist for trkB, matrices which are in the form of shaped articles, for example films or microcapsules. Examples of sustained release matrices include polyesters, hydrogels (eg, poly (2-hydroxyethyl-methacrylate) or poly (vinyl alcohol)), polylactides (U.S. Patent No. 3,773,919), L-glutamic acid copolymers and 7-ethyl-L-glutamate, non-degradable ethylene vinyl acetate, degradable lactic acid-glycolic acid copolymers such as LUPRON DEPOT ™ (injectable microspheres composed of copolymer of lactic acid-glycolic acid and leuprolide acetate), acetate-sobutyrate sucrose and poly-D - (-) - 3-hydroxybutyl acid. Another example of a sustained release drug delivery system that can be used is the ATRIGEL® manufactured by Atrix Laboratories. See, for example, United States Patent No. 6,565,874. The ATRIGEL® drug delivery system consists of biodegradable polymers, similar to those used in biodegradable sutures, dissolved in biocompatible vehicles. The agonists for trkB can be mixed in this liquid delivery system at the time of manufacture or, depending on the product, can then be added by the physician at the time of use. When the liquid product is injected subcutaneously or intramuscularly via a small-gauge needle or into tissue sites accessible through a cannula, the displacement of the vehicle with water in the tissue fluids causes the polymer to precipitate into a film or solid implant. The trkB agonists encapsulated in the implant are then released in a controlled manner as the polymer matrix degrades over time. Depending on the patient's medical needs, the Atrigel system can administer proteins for a period ranging from days to months. Injectable sustained release systems, such as ProLease®, Medisorb®, manufactured by Alkermes can also be used. In some embodiments, the invention provides compositions (which are described herein) for use in any of the methods described herein, either in the context of use as a medicament and / or use for the manufacture of a medicine.

NT-4/5 Polypeptides The agonist for trkB that is used in the methods of the invention includes NT-4/5 polypeptides. As used herein "NT-4/5 polypeptide" includes natural mature protein (which is interchangeably referred to as "NT 4/5") such as the mature human NT-4/5 shown in the Table. 1 later, and in U.S. Patent Application Publication No. 2005/0209148 and PCT WO 2005/08240 and Figure 1 of U.S. Patent Application Publication No. 20030203383 and the variants of natural amino acid sequences of NT-4/5; variants of the amino acid sequences of NT-4/5; peptide fragments of mature NT-4/5 (such as human) and variants of amino acid sequences; and modified forms of mature NT-4/5 and said variants of amino acid sequences and peptide fragments in which the polypeptide or peptide has been modified covalently by substitution with a residue other than a natural amino acid, insofar as the variant of the amino acid sequence, the peptide fragment and the modified form of the same show one or more biological activities of an agonist for trkB and / or natural mature NT-4/5 protein. The agonist for trkB also includes fusion proteins and conjugates comprising any of the NT-4/5 polypeptide modalities described herein, for example, a conjugated or fused NT-4/5 polypeptide with a moiety that enhances the half-life, such as PEG, Fe region of IgG, albumin or a peptide. Variants of amino acid sequences, peptide fragments (including fragment variants), or modified forms thereof considered do not include NGF, BDNF, or NT-3 of any animal species. Variants, peptide fragments, and modified forms of natural NT-4/5 are described in U.S. Patent Application Publication Nos. 2003/0203383: 2002/0045576; 2005/0209148; U.S. Patent Nos. 5,702,906; 6,506,728; 6,566,091; 5,830,858. The NT-4/5 polypeptides include one or more of the embodiments described herein. For example, the NT-4/5 polypeptide comprises a natural sequence with one or more amino acid insertions, deletions, or substitutions.

TABLE 1 Amino acid sequence of mature human NT-4/5 and mature human NT-4/5 human nucleotide sequence Amino acid sequence (SEQ ID NO: 1): GVSETAPASRRGELAVCDAVSGWVTDRRTAVDLRGREVEVLGEVPAAGGSPLRQYFFETR CKADNAEEGGPGAGGGGCRGVDRRHWVSECKAKQSYVRALTADAQGRVG RÍRÍDTACVC TLLSRTGRA Nucleotide sequence (SEQ ID NO: 2): GGGGTGAGCG AAACTGCACCAGCGAGTCGTCGGGGTGAGCTGGCTGTGTGCGATGCAGTC AGTGGCTGGGTGACAGACCGCCGGACCGCTGTGGACTTGCGTGGGCGCGA GGTGGAGGTGTTGGGCGAGGTGCCTGCAGGTGGCGGCAGTCCCCTCCGCC AGTACTTCTTTGAAACCCGCTGCAAGGCTGATAACGCTGAGGAAGGTGGC CCGGGGGCAGGTGGAGGGGGCTGCCGGGGAGTGGACAGGAGGCACTGGGT ÁTCTGAGTGCAAGGCCAAGCAGTCCTATGTGCGGGCATTGACCGCTGATG- CCCAGGGCCGTGTGGGCTGGCGATGGATTCGAATTGACACTGCCTGCGTC TGCACACTCCTCAGCCGGACTGGCCGGGCCTGAG In some embodiments, the NT-4/5 polypeptide is a mammalian NT-4/5 polypeptide which can be a natural mammalian NT-4/5, or an NT-4/5 polypeptide that is derived from NT- 4/5 of a natural mammal and having a sequence that does not correspond to any part of NT-4/5 that is not a natural mammal. In some embodiments, the NT-4/5 polypeptide is a human NT-4/5 polypeptide which can be a natural human NT-4/5, or an NT-4/5 polypeptide derived from a natural human NT-4/5. and that it has a sequence that does not correspond to any part of a natural non-human NT-4/5. The Polypeptides NT-4/5, which includes variants, fragments peptides. Modified forms of NT-4/5 polypeptides (including native NT-4/5), fusion protein and conjugate of the invention are characterized by any (one or more) of the following characteristics: (a) binding to a trkB receptor; (b) binding to a trkB receptor and activating the biological activity (s) for trkB and / or one or more downstream routes mediated by the signaling function (s) for trkB; (c) binding to a trkB receptor and increasing body weight and / or food intake in a primate when administered peripherally; (d) binding to a trkB receptor and treating, preventing, reversing or ameliorating one or more symptoms of cachexia or unwanted weight loss in a primate when administered peripherally; (e) binding to a trkB receptor and treating, preventing, reversing or ameliorating one or more symptoms of anorexia nervosa in a primate when administered peripherally; (f) binding to a trkB receptor and treating, preventing, reversing or ameliorating one or more symptoms of opioid-induced emesis in a mammal when administered, peripherally: (g) promoting dimerization and activation of the trkB receptor; and (h) increase neuronal survival dependent on the trkB receptor and / or neurite growth. Thus all NT-4/5 polypeptides (including variants, fragments, and modified forms) are functional as described above. The biological activity of the variants can be analyzed in vitro and in vivo using methods known in the art and methods described herein. The procedures described in this document may also be used to identify a agonist against trkB. The NT-4/5 polypeptides can exhibit enhanced activity or reduced activity compared to a native NT-4/5 protein. In some embodiments, the functionally equivalent variants have at least approximately either 50%, 60%, 70%, 75%, 80%, 85%, 90%, or 95% activity compared to the native NT-4/5 protein. from which the NT-4/5 polypeptide is derived with respect to one or more of the biological assays described above (or that are known in the art). In some embodiments, the functionally equivalent variants have an EC50 (half the effective minimum concentration) of less than about either 0.01 nM, 0.1 nM, 1 nM, 10 nM or 1 00 nM in activation of the trkB receptor in vitro ( for example assays that are described in Example 6, and in documents US 2005/0209148 and PCT WO 2005/082401). The amino acid sequence variants of NT-4/5 include polypeptides having an amino acid sequence that differs from natural NT-4/5 by the insertion, deletion and / or substitution of one or more amino acid residues of the NT- sequence. 4/5 natural (for example, NT-4/5 mature human shown in Table 1). The amino acid sequence variants will generally be at least about 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to any NT-4 / 5 natural (such as mature human NT-4/5 which is shown in SEQ ID NO: 1). In some embodiments, the variant is at least approximately 70% identical to the amino acid sequence of the SEC. ID.

No.: 1 In some embodiments, the variant is at least approximately 85% identical to the amino acid sequence of the SEC. ID. No.: 1 In some embodiments, the variant is at least approximately 90% identical to the amino acid sequence of the SEC. ID. No.: 1 In some embodiments, the variant is at least approximately 95% identical to the amino acid sequence of the SEC. ID. No.: 1 The amino acid sequence variants of NT-4/5 can be generated by performing predetermined mutations to previously isolated NT-4/5 DNA. Amino acid variants can be designed and generated based on the crystal structure of NT-4/5 and the trkB receptor, Banfield et al., Structure 9: 1 191 -9 (2001). For example, amino acids that are not directly involved in the interaction between the monomers of NT-4/5 and between NT-4/5 and the trkB receptor can be mutated, for example, to introduce a PEG binding site. Techniques known in the art can be used to design variants of NT-4/5 polypeptides that exhibit one or more enhanced or reduced biological activities compared to native NT-4/5 protein. There are two main variables to consider when making these predetermined mutations: the location of the mutation site and the nature of the mutation. In general, the location and nature of the mutation that is chosen generally depend on the characteristic of NT-4/5 to be modified. For example, antagonists or NT-4/5 superagonists can be initially selected by localizing the amino acid residues that are identical or highly conserved between NGF, BDNF, NT-3, and NT-4. These remnants can then be modified in series, for example, (1) replacing first with conservative choices and then with more radical selections depending on the results that are achieved, (2) eliminating the target rest, or (3) inserting remnants of the same. class or a different one adjacent to the localized site or combinations of options 1-3. One useful technique is called "wing scanning." Here, an amino acid residue or a group of target moieties is identified and replaced by alanine or polyalanine. The domains demonstrating a functional sensitivity to alanine substitutions are then defined by introducing more variants or others into or through the sites of alanine substitution. Obviously, said variations which, for example, convert NT-4/5 into NGF, BDNF or NT-3 are not included in the scope of this invention. Thus, although the site for introducing a variation of the amino acid sequence is predetermined, the nature of the mutation per se need not be predetermined. For example, to optimize the functioning of a mutation at a given site, a wing scan or random mutagenesis is performed on the target codon or region and the NT-4/5 variants are screened to determine the desired activity. Deletions of amino acid sequences generally vary in the range from about 1 to 30 residues, more preferably, from about 1 to 10 residues, and are usually contiguous Deletions can be introduced in regions of low homology between BDNF, NGF, NT-3 and NT-4/5 to modify the activity of NT-4/5. Deletions of NT-4/5 in areas of substantial homology with BDNF, NT-3, and NGF may have a greater likelihood of modifying the biological activity of NT-4/5 more significantly. The number of consecutive deletions can be selected so as to preserve the tertiary structure of NT-4/5 in the affected domain, for example, beta-folded sheet or alpha helix. Inserts in the amino acid sequences include fusions at the amino and / or carboxyl termini ranging in length from a moiety to polypeptides containing one thousand or more residues, as well as intrasequence insertions of a single or multiple amino acid residues. The intrasequence insertions (i.e., insertions in the mature NT-4/5 sequence) can generally vary from about 1 to 10 residues, more preferably, from 1 to 5, most preferably 1 to 3. An example of a terminal insert includes the fusion of a heterologous signal sequence at the N-terminus at the N-terminus of the NT-4/5 molecule to facilitate the secretion of mature NT-4/5 by the recombinant host. Said signals will generally be homologous to the host cell that is intended and include STII or Ipp for E. coli, alpha factor for yeast and viral signals such as herpes gD for mammalian cells. Other insertions include fusion of a polypeptide at the N or C terminus of NT-4/5. Another group of variants includes those in which at least one amino acid residue of NT-4/5 has been removed, and preferably only one, and a different remainder is inserted in its place. One example is the replacement of arginine and lysine by other amino acids to make NT-4/5 resistant to proteolysis by serine proteases, thus creating a variant of NT-4/5 that is more stable. The sites of greatest interest for substitution mutagenesis include sites in which the amino acids found in BDNF, NGF, NT-3, and NT-4 are substantially different in terms of volume, charge or hydrophobicity of the side chain, but in which there is also a high degree of homology at the selected site between various animal analogs of NGF, NT-3, and BDNF (for example among all animal NGFs, all NT-3 animals and all animal BDNFs). This analysis will highlight the remains that may be involved in the differentiation of the activity of the trophic factors and, therefore, the variants in these sites may affect these activities. Examples of such sites in mature human NT-4/5 numbered from the N-terminus and exemplary substitutions include G77 to K, H, Q or R and R84 to E, F, P, Y or W of NT-4 / 5 of the SEC. ID. No.: 1, respectively. Other sites of interest are those in which the remains are identical between the BDNF, NGF, NT-3, and NT-4/5 of all animal species. This degree of conformation suggests the importance of achieving a common biological activity to the four factors. For example, substitution of one or more amino acids includes conservative substitutions. The methods of making conservative substitutions are known in the art. For example, wing (A) can be replaced by val, leu, ile, preferably by val; arg (R) can be substituted by lys, gln, asn, preferably by lys; asn (N) can be replaced by gln, his, lys, arg, preferably by gln; asp (D) can be replaced by glu; cys (C) can be replaced by being; gln (O) can be replaced by asn; glu (E) can be replaced by asp; gly (G) can be replaced by pro; his (H) can be replaced by asn, gln, lys, arg; preferably by arg; ile (I) can be replaced by leu, val, met, ala, phe, norleucine, preferably by leu; leu (L) can be replaced by norleucine, ile, val, met; to; phe, preferably by ile; lys (K) can be replaced by arg; gln, asn, preferably by arg; met (M) can be replaced by leu; phe; ile, - preferably by leu; phe (F) can be replaced by leu, val, ile, ala, preferably by leu; pro (P) can be replaced by gly; being (S) can be replaced by thr; thr (T) can be replaced by being; trp (W) can be substituted by tyr, tyr (Y) can be substituted by trp, phe, thr, ser, preferably by phe; val (V) can be replaced by ile; leu; met; phe, wing; norleucine, preferably by leu. Particularly suitable sites for conservative substitutions include, numbered from the N-terminus of mature human NT-4 (SEQ ID NO: 1), R1 1, G12, E13, V16, D18, W23, V24, D26, V40, L41, Q54, Y55, F56, E58, T59, G77, R79, G80, H85, W86, A99, L100,? 10? , W1 10, R1 1 1, W1 12. 11 13, R1 14, 11 15, D1 16, and A1 18. Residues of cistern not involved in maintaining the proper conformation of NT-4/5 can also be substituted, generally with serine, to improve the oxidative capacity of the molecule and prevent aberrant cross-linking. Sites other than those described in this paragraph are adequate for the deletion or insertion studies described above. Substantial modifications can be achieved by selecting substitutions that differ significantly in their effect on the maintenance of (a) the skeletal structure of the polypeptide in the area of substitution, eg, in the form of sheet or helical conformation, (b) the charge or hydrophobicity of the molecule at the target site, or (c) the volume of the side chain. The natural remains are divided into groups based on the common properties of the side chains (some of these may correspond to different functional groups): (1) hydrophobic: norleucine, met, ala, val, leu, ile; (2) neutral hydrophilic: cys, ser, thr; (3) acids: asp, glu; (4) basic: asn, gln, his, lys, arg; (5) residues that influence the orientation of the chain: gly, pro; and (6) aromatics: trp, tyr, phe. Non-conservative substitutions will involve exchanging a member of one of these classes for another. Examples of variants include NT-4: the polypeptide of SEQ. ID. No.: 1 with mutation from E67 to S or T (this adds an N-linked glycosylation site); the polypeptide of the amino acid residue R83 to Q94, G1 to C61, G1 to C1 7, C17 to C61, G17 to C78, C17 to C90, C17 to C1 19, C17 to C121, R1 1 to R27, R1 1 to R34, R34 to R53, C61 to C78, R53 to C61, C61 to C1 19, C61 to C78, C78 to C1 19, C61 to C90, R60 to C78, K62 to C1 19, K62 to K91, R79 to R98, R83 to K93, ?? 01 to R1 1 1, G1 to C121 of the SEC. ID. No.: 1; the polypeptide comprises V40-C121 of SEQ. ID. No.: 1, for example, V40-C121 of the SEC. ID. No.: 1 fused to a polypeptide at the N-terminus and / or at the C-terminus; the polypeptide comprising SEC. ID. No.: 1 with deletion of C78, C61, Q54-T59, R60-D82, H85-S88, W86-T101 (deletions of the tract of residues indicated, inclusive); SEC. ID. No.: 1 with mutation from R53 to H, from K91 to H, from V108 to F, from R84 to Q, H, N, T, Y or W, and from D1 16 to E, N, Q, Y, S or T. Also included is NT-4/5 (SEQ ID NO: 1) in which position 70 is substituted with an amino acid residue other than G, E, D or P; position 71 with another amino acid other than A, P or M; and / or position 83 with another amino acid other than R, D, S or K; as well as cyclized fragments of NT-4. It is said that two polynucleotide or polypeptide sequences are "identical" if the nucleotide or amino acid sequence of the two sequences is the same when aligned for maximum correspondence as described below. Comparisons between two sequences are usually performed by comparing the sequences in a comparison window to identify and compare the local regions of similarity of the sequences. A "comparison window" as used herein, refers to a segment of at least about 20 contiguous positions, 30 to about 75, 40 to about 50, in which a sequence can be compared to a reference sequence. of the same number of contiguous positions after aligning the two sequences optimally. Optimal alignment of sequences for comparison can be performed using the Megalign program from the Lasergene series of bioinformatics software programs (DNASTAR, Inc., Madison, Wl), using the default parameters. This program includes various alignment schemes that are described in the following references: Dayhoff, M.O. (1978) A model of evolutionary change in proteins - Matrices for detecting distant relationships. In Dayhoff, M.O. (ed.) Atlas of Protein Sequence and Structure, National Biomedical Research Foundation, Washington DC Vol. 5, Suppl. 3, pages 345-358; Hein J. 1990, Unified Approach to Alignment and Phylogenes pages 626-645 Methods in Enzymology vol. 183, Academic Press, Inc., San Diego, CA; Higgins, D.G. and Sharp, P.M., 1989, CABIOS 5: 1 51-153; Myers, E. W. and Muller W., 1988, CABIOS 4: 1-17; Robinson, E.D., 1 971; Comb Theor. 1 1: 105; Santou, N., Nes, M., 1987, Mol. Biol. Evol. 4: 406-425; Sneath, P.H.A. and Sokal, RR., 1973. Numerical Taxonomy: The Principles and Practice of Numerical Taxonomy, Freeman Press, San Francisco, CA; Wilbur, VV.J. and Lipman, D.J., 1983, Proc. Nati Acad. Sci. USA 80: 726-730. Preferably, the "percent identity of the sequences" is determined by comparing two optimally aligned sequences in a comparison window of at least 20 positions, wherein the portion of the polynucleotide or polypeptide sequence of the comparison window may comprise additions or deletions (ie gaps) of 20 per one hundred or less, usually 5 to 1 5 percent, or 10 to 12 percent, with respect to the reference sequences (which do not comprise additions or deletions) for optimal alignment of the two sequences. The percentage is calculated by determining the number of positions in which the bases of nucleic acid bases or identical amino acid residues are found in both sequences to obtain the number of positions that coincide, dividing the number of positions that coincide among the total number of positions of the reference sequence (ie, the size of the window) and multiplying the results by 100 to obtain the percentage of identity of the sequences. Variants of the NT-4/5 amino acid sequences can be natural or can be prepared synthetically, such as by introducing appropriate nucleotide changes into a previously isolated NT-4/5 DNA or by in vitro synthesis of the polypeptide variant which is desired As indicated above, said variants may comprise deletions, or insertions or substitutions, of one or more amino acid residues within the mature NT-4/5 amino acid sequence (eg, the sequence shown in Table 1) . Any combination of deletion, insertion, and substitution is performed to obtain an amino acid sequence variant of NT-4/5, with the proviso that the polypeptide variant possesses a desired characteristic. The amino acid changes can also produce additional modifications of NT-4/5 after expression in recombinant hosts, for example introducing or moving glycosylation sites, or introducing anchoring sequences to the membrane (see, for example, PCT WO 89/01041). In some embodiments, the NT-4/5 polypeptide comprises an amino acid sequence encoded by a nucleic acid that hybridizes under stringent conditions to a nucleic acid sequence (e.g., SEQ ID NO: 2) that encodes NT-4/5 mature human. The polynucleotide variants also, alternatively, may be substantially homologous to a native gene, or to a portion or complement thereof. Said polynucleotide variants can hybridize under moderately restrictive conditions to a natural DNA sequence encoding the polypeptide (or a complementary sequence). Suitable "moderately restrictive conditions" include prewash in a solution of 5 X SSC, 0.5% SDS, 1.0 mM EDTA (pH 8.0); Hybridization at 50 ° C-65 ° C, 5 X SSC, overnight; followed by washing twice at 65 ° C for 20 minutes with each of the 2X, 0.5X and 0.2X SSC containing 0.1% SDS. As used herein, "highly restrictive conditions" or "conditions of high restriction" are those that: (1) employ a low ionic strength and a high temperature for washing, for example 0.015 M sodium chloride, 0.0015 sodium citrate M, 0.1% sodium dodecyl sulfate at 50 ° C; (2) employ during denaturation a denaturing agent, such as formamide, for example, 50% (v / v) formamide with 0.1% bovine serum albumin / 0.1% Ficoll / 0.1% polyvinylpierrolidone / sodium phosphate buffer 50 mM at pH 6.5 with 750 mM sodium chloride, 75 mM sodium citrate at 42 ° C; or (3) employ 50% formamide, 5 X SSC (0.075 M NaCl, 0.075 M sodium citrate), 50 mM sodium phosphate (pH 6.6), 0.1% sodium pyrophosphate, 5 x Denhardt's solution, salmon sperm DNA subjected to ultrasound (50 pg / ml), 0.1% SDS, and 10% dextran sulfate at 42 ° C, washed at 42 ° C in 0.2 x SSC (sodium chloride / sodium citrate and 50% formamide at 55 ° C, followed by a very restrictive wash consisting of 0.1 x SSC containing EDTA at 55 ° C. Other exemplary stringent hybridization conditions in 50% formamide, 5 x SSC, 0.1% sodium dodecyl sulfate, 0.1% sodium pyrophosphate , 50 mM sodium phosphate pH 6.8, 2 x Denhardf's solution, and 10% dextran sulfate at 42 ° C, followed by a wash in 0.1 x SSC and 0.1% SDS at 42 ° C. The experienced person will recognize how to adjust the temperature, the ionic power, etc. as necessary to accommodate factors such as the length of the probe and the like. Those of ordinary skill in the art will appreciate that, as a result of the degeneracy of the genetic code, there are many nucleotide sequences encoding a polypeptide as described herein. Some polynucleotide hedges have minimal homology to the nucleotide sequence of any native gene. However, polynucleotides that vary due to differences in the use of the codons are contemplated specifically by the present invention. In addition, alleles of the genes comprising the polynucleotide sequences that are provided herein are within the scope of the present invention. Alleles are endogenous genes which are altered as a result of one or more mutations, such as deletions, additions and / or nucleotide substitutions. The resulting mRNA and protein may have, but not necessarily, an altered structure or function. Alleles can be identified using standard techniques (such as hybridization, amplification and / or comparison between database sequences). The agonists for trkB that are used in the methods of the invention also include fusion proteins comprising the amino acid sequence of NT-4/5 (e.g., human NT-4/5 shown in Table 1) or a functional peptide fragment thereof. Biologically active NT-4/5 polypeptides can be fused with sequences, such as sequences that enhance the immunological reactivity, facilitate coupling of the polypeptide to a support or a carrier, or facilitate folding and / or purification (e.g. , sequences encoding epitopes such as Myc, HA derived from influenza virus hemagglutinin, His-6, FLAG). These sequences can be fused to an NT-4/5 polypeptide at the N-terminus or C-terminus. In addition, the protein or polynucleotide can be fused with other polypeptides that increase its function or specify its location in the cell, such as a sequence of secretion. Methods for producing recombinant fusion proteins that are described above are known in the art. The recombinant fusion protein can be produced, folded and isolated by well-known procedures in the art.

The NT-4/5 polypeptides described herein may be modified to increase their half-lives in an individual. For example, the NT-4/5 polypeptide can be pegylated to reduce systemic clearance with minimal loss of biological activity. The invention also provides compositions (including pharmaceutical compositions) comprising an NT-4/5 polypeptide linked to a PEG molecule. In some embodiments, the PEG molecule is linked to the NT-4/5 polypeptide through a reversible linkage. The half-life of a pegylated NT-4/5 polypeptide can be increased by more than about 2 times, 5 times, 10 times, 20 times and 30 times compared to the half-life of the non-pegylated NT-4/5 polypeptide. The polyethylene glycol (PEG) polymers can be linked to various functional groups of the NT-4/5 polypeptide using procedures known in the art. See, for example, Roberts and cois. Advanced Drug Delivery Reviews 54: 459-416 (2002); Sakane and cois. Pharm. Res. 14: 1086-91 (1991). The PEG can be linked to the following functional groups of the polypeptide: amino groups, carboxyl groups, modified or natural N-termini, amino groups and thiol groups. In some embodiments, one or more surface amino acid residues are modified with PEG molecules. The PEG molecules can be of various sizes (for example, ranging from about 2 to 40 kDa). The PEG molecules linked to the NT-4/5 polypeptide can have a molecular weight of about 2000, 10,000, 15,000, 20,000, 25,000, 30,000, 35,000, 40,000 Gives. The PEG molecule can be a single or branched chain. To link PEG and the NT-4/5 polypeptide, a PEG derivative having a functional group at one or both ends can be used. The functional group is chosen based on the type of reactive group available in the NT-4/5 polypeptide. Methods for linking binding derivatives to polypeptides are known in the art. Roberts et al., Advanced Drug Delivery Reviews 54: 459-476 (2002). The link between the NT-4/5 polypeptide and the PEG can also be such that it can be cleaved or naturally degraded (reversible or degradable link) in an individual which can improve the half-life but minimize the loss of activity. The PEG binding site in the NT-4/5 polypeptide can also be created by mutating the surface residues a to an amino acid residue having a group that reactions with PEG, such as, a cysteine. For example, the following amino acids of human NT-4/5 (SEQ ID NO: 1) can be mutated for the binding of PEG G1, V2, S3, E4, T5, S9, R10, T25, D26, R28 , T29, V31, E37, E39, L41, E43, A46, A47, G48, G49, S50, R53, D64, N65, A66, E67, E68, G69, D82, R83, R84, H85, A104, Q105, G106 , R107, V108, S125, and T127. These can be applied to the corresponding remains of other species. Various pegylated NT-4/5's have been generated and are shown in Examples 6 and 7 of U.S. Patent Application Publication No. 2005/0209148 and PCT WO 2005/082401. The remaining serine from position 60 of the mature human NT-4/5 can be changed to cysteine to generate NT4-S50C which is then pegylated, in which the PEG is bound with the cysteine at position 50. An example of a specific binding at the N-terminus for PEG is to mutate the rest of position 1 to a serine or threonine, followed by pegylation, in which the PEG binds to the serine of position 1 The NT-4/5 polypeptide can be produced by recombinant means, i.e., by expression of the nucleic acid encoding the NT-4/5 polypeptide in recombinant cell culture, and, optionally with purification of the variant of the cell culture polypeptide, for example, by bioassay of the activity of the variant or by absorption in an immunoaffinity column comprising polyclonal rabbit antibodies against NT-4/5 (which bind to at least one immune epitope of the variant which is also present in NT). -4/5 native). Small peptide fragments, of the order of 40 residues or less, are conveniently prepared by in vitro procedures. The DNA encoding the NT-4/5 polypeptide can be cloned into an expression vector to express the protein in a host cell. Examples of nucleic acids encoding the NT-4/5 polypeptide are described in U.S. Patent Application Publication No. 2003/0203383. The DNA encoding the NT-4/5 polypeptide in its mature form can be linked at its amino terminus to a secretion signal. This secretion signal is preferably the NT-4/5 presequence that normally drives the secretion of NT-4/5 in human cells in vivo. However, adequate secretion signals also include signals from other NT-4/5 animals, signals of NGF, NT-2, or NT-3, viral signals or signals of segregated polypeptides of the same or related species. Any host cell (such as E. coli) can be used to express the protein or polypeptide. The expressed NT-4/5 polypeptide can be purified. The polypeptide NT-4/5 can be recovered from the culture medium in the form of a secreted protein, although it can also be recovered from lysates of host cells when directly expressed without secretion signal. Protein purification procedures known in the art can be used. The methods for producing the NT-4/5 polypeptide and purifying the expressed NT-4/5 polypeptide are described in U.S. Patent Application Publication No. 2003/0203383, and in U.S. Patent No. 6, 184.360. The NT-4/5 polypeptide can be expressed in E. coli and folded according to procedures known in the art. Mature human NT-4/5 can also be obtained commercially (for example, in R &D Systems, Minneapolis, MN, Sigma, St. Louis, MO, and Upstate Biotech., Temecula, CA).

Polypeptides and antibodies against agonist for trkB The agonist for trkB that is used in the methods of the invention also includes polypeptides against agonist for trkB, which include antibodies against agonists for trkB. A polypeptide against agonist for trkB (eg, an antibody) should show any one or more of the following characteristics: (a) join a trkB receiver; (b) joining a trkB receptor and activating the biological activity (s) for trkB and / or one or more downstream routes mediated by the signaling function (s) for trkB; (c) binding to a trkB receptor and increasing body weight and / or food intake in a primate when administered peripherally; (d) binding to a trkB receptor and treating, preventing, reversing or ameliorating one or more symptoms of cachexia or unwanted weight loss in a primate when administered peripherally; (e) binding to a trkB receptor and treating, preventing, reversing or ameliorating one or more symptoms of anorexia nervosa in a primate when administered peripherally; (f) binding to a trkB receptor and treating, preventing, reversing or ameliorating one or more symptoms of opioid-induced emesis in a mammal when administered, peripherally: (g) promoting dimerization and activation of the trkB receptor; and (h) increase neuronal survival dependent on the trkB receptor and / or neurite growth. In some embodiments, the polypeptide against agonist for trkB (eg, antibody) is multivalent and binds to the extracellular domain of a trkB receptor. It has been shown that immunoglobulins that have the ability to bind and cross-link or dimerize the trk family of neurotrophin receptors activate these receptors and produce consequences in neurons that are similar to exposure to a neurotrophin. See, U.S. Patent No. 6,656,465: and PCT WO 01/98361. Antibodies against agonists for trkB can encompass monoclonal antibodies, polyclonal antibodies, fragments of antibodies (for example Fab, Fab ', F (ab') 2, Fv, Fe, etc.), chimeric, single chain antibodies (ScFv), their mutants; fusion proteins comprising a portion of antibody and any other modified configuration of the immunoglobulin molecule comprising an antigen recognition site of the required specificity. The antibodies can be murine, rat, human or any other origin (which includes humanized antibodies). In some embodiments, the polypeptide (which includes the antibody) binds to trkB and does not react (bind) significantly with other neurotrophin receptors (such as the related neurotrophin receptors, trkA and / or trkC). The polypeptide against trkB agonist can bind to human trkB. The polypeptide against trkB agonist can also bind to human and rodent trkB. In some embodiments, the trkB agonist polypeptide can bind to human and rat trkB. In some embodiments, the trkB agonist polypeptide can bind to human and mouse trkB. In one embodiment, the polypeptide recognizes one or more epitopes from the extracellular domain for human trkB. In another embodiment, the antibody is a mouse or rat antibody that recognizes one or more epitopes of the extracellular domain for human trkB. In some embodiments, the polypeptide binds to human trkB and does not bind significantly to trkB from another mammalian species (in some embodiments, vertebrate species). In some embodiments, the polypeptide binds to human trkB as well as to one or more trkB from other mammalian species (in some embodiments, species vertebrates). In another embodiment, the polypeptide recognizes one or more epitopes of a trkB that is selected from one or more of primate, canine, feline, equine and bovine. In some embodiments, the functionally equivalent variants have an EC50 (half the effective minimum concentration) of less than about either 0.01 nM, 0.1 nM, 1 nM, 10 nM or 1 00 nM in activation of the trkB receptor in vitro ( for example assays that are described in Example 6, and in documents US 2005/0209148 and PCT WO 2005/082401). The binding affinity of the trkB agonist polypeptide (eg, antibody) to trkB can be any of about 500 nM, about 400 nM, about 300 nM, about 200 nM. about 100 nM, about 50 nM, about 10 nM, about 1 nM, about 500 pM, about 100 pM, or about 50 pM to either about 2 pM, about 5 pM, about 10 pM, about 1.5 pM, about 20 pM pM, or approximately 40 pM. In some embodiments, the binding affinity is either approximately 100 nM, approximately 50 nM, approximately 10 nM, approximately 1 nM, approximately 500 pM, approximately 1000 pM, or approximately 50 pM, or less than approximately 50 pM. In some embodiments, the binding affinity is less than any of about 100 nM, about 50 nM, about 10 nM, approximately 1 nM, approximately 500 pM, approximately 1000 pM, or approximately 50 pM. In still other embodiments, the binding affinity is about 2 pM, about 5 pM, about 10 pM, about 15 pM, about 20 pM, about 40 pM or greater than about 40 pM. As is known in the art, the binding affinity can be expressed in terms of KD, O dissociation constant, and a higher binding affinity corresponds to a lower KD. One way to determine the binding affinity of the antibodies to trkB is to measure the binding affinity of Fab fragments of the monofunctional antibody. To obtain monofunctional Fab fragments, an antibody (e.g., IgG) can be cleaved with papain or expressed recombinantly. The affinity of a fragment of an antibody against trkB can be determined by surface plasmon resonance (BIAcore3000 ™, surface plasmon resonance system (SPR), BIAcore, INC, Piscataway NJ). The CM5 chips can be activated with N-ethyl-N '- (3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) according to the supplier's instructions. Fusion protein can be diluted for trkB-Fc ("htrkB") (or any other trkB, such as rat trkB) in 10 mM sodium acetate at pH 5.0 and injected onto the activated chip at a concentration of 0.0005 mg / ml. Using variable creep time for the individual chip channels, two antigen density ranges can be achieved: 200-400 response units (UR) for detailed kinetic studies and 500-1000 UR for screening tests. The chip can be blocked with ethanolamine. Regeneration studies have shown that a mixture of Pierce elution buffer (No. of product 21004. Pierce Biotechnology, Rockford, IL) and 4M NaCl (2: 1) effectively removes bound Fab at the same time as maintains the htrkB activity of the chip during more than 200 injections. The HSS-EP buffer (0.01 M HEPES, pH 7.4, 0.15 M NaCl, 3 mM EDTA, 0.005% surfactant P29) is used as a processing buffer for the BIAcore assays. Serial dilutions (0.1 - 10 x KD estimated) of the purified Fab samples are injected for 1 minute at 100 μm / min and dissociation times of up to 2 hours are allowed. The concentrations of the Fab proteins are determined by ELISA and / or electrophoresis on SDS-PAGE using a Fab of known concentration (as determined by amino acid analysis) as a standard. Kinetic association velocities (Kon) and dissociation rates (K0ff) (generally measured at 25 ° C) are obtained simultaneously by entering the data in a 1: 1 binding model of Langmuir (Karlsson, R. Roos, H. Fagerstam, L. Petersson, B. (1994), Methods in Enzymology 6: 99-1 10) using the BIAevaluation program. The equilibrium dissociation constant values (K0) are calculated in terms of In some embodiments, the anti-agonist polypeptide for trkB (including antibody) exhibits reduced effector function. As used herein, an antibody or a polypeptide having a "Reduced effector function" (which is used interchangeably with the term "immunologically inert" refers to antibodies or polypeptides that have no effector function or that have reduced activity or activities of effector function (compared to an antibody or polypeptide having a constant unmodified or natural region), for example, having no activity or having reduced activity in one or more of the following: a) triggering complement-mediated lysis; b) stimulate antibody-dependent cell-mediated cytotoxity (ADCC); and C) activate the microglia. Effector function activity may be reduced by approximately 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99% and 100%. In some embodiments, the antibody binds to a trkB receptor without triggering significant complement-dependent lysis or cell-mediated destruction of the tt. For example, the Fe receptor binding site of the constant region can be modified or mutated to eliminate or reduce binding affinity to certain Fe receptors, such as FcvRI, FCYRI I, FCYRI I I, and / or FcyRIV. For simplicity, the antibodies will be referred to as understanding that the modalities also apply to the polypeptides. The numbering system (Kabat et al., Sequences of Proteins of Immunological Interest, (5th edition, 1991, National Institutes of Health, Bethesda MD, 1991) is used to indicate which amino acid residue (s) of the constant region (for example, of an IgG antibody) are altered or mutated.The numbering can be used for a specific type of antibody (for example, IgG1) or a species (eg example, human being) understanding that similar changes can be made between types of antibodies and species. In some embodiments polypeptides (including antibodies) that specifically bind to a trkB receptor comprise a heavy chain constant region that has reduced effector function. The constant region of the heavy chain may have a natural sequence or is a variant. In some embodiments, the amino acid sequence of a constant region of a natural heavy chain is mutated, for example, by substitution, insertion and / or deletion of amino acids, whereby the effector function of the constant region is reduced. In some modalities, the N-glycosylation of the Fe region of a constant region of the heavy chain can also be changed, for example, it can be completely or partially eliminated, whereby the effector function of the constant region is reduced. In some embodiments, the effector function is reduced by eliminating N-glycosylation of the Fe region (e.g., from the CH 2 domain of IgG). In some embodiments, the N-glycosylation of the Fe region is eliminated by mutating the glycosylated amino acid residue or the adjacent residues that are part of the glycosylation recognition sequence of the constant region. The sequences of tripeptides asparagine-X-serine (NXS), asparagine-X-threonine (NXT) and asparagine-X-cysteine (NXC), where X is any amino acid except proline, are the recognition sequences for the enzymatic binding of the rest of carbohydrate to the chain Asparagine side effect for N-glycosylation. Mutation of any of the amino acids of the tripeptide sequences of the constant region provides a non-glycosylated IgG. For example, the N-glycosylation site N297 of human IgG1 and IgG3 can be mutated to A, D, Q, K or H. See, Tao et al., J. Immunology 143: 2595-2601 (1989); and Jefferis et al., Immunological Reviews 163: 59-76 (1998). It has been reported that lgG1 and IgG3 with substitution of Asn-297 for GIn, His or Lys do not bind to the human FcyRI and do not activate complement, completely losing the binding capacity of C1q for IgG1 and dramatically reducing for IgG3. In some embodiments, the amino acid N of the tripeptide sequences is mutated to any one of amino acids A, C, D, E, F, G, H, I, K, L, M, P, Q, R, S, T, V, W, Y. In some embodiments, the amino acid N of the tripeptide sequences is mutated to a conservative substitution. In some embodiments, amino acid X of the tripeptide sequences is mutated to proline. In some embodiments, the amino acid S of the tripeptide sequences is mutated to A, D, E, F, G, H, I, K, L, M, N, P, Q, R, V, W, Y. some embodiments, the amino acid T of the tripeptide sequences is mutated to A, D, E, F, G, H, I, K, L, M, N, P, Q, R, V, W, Y. In some modalities, amino acid C of the tripeptide sequences is mutated to A, O, E, F, G, H, K, L, M, N, P, Q, R, V, W, Y. In some embodiments, the The amino acid following the tripeptide is mutated to P. In some embodiments, the N-glycosylation of the constant region is enzymatically removed (such as N-glucosidase F, endoglucosidase F1, endoglucosidase F2, endoglycosidase F3 and endoglucosidase H). The elimination of N-glycosylation can also be achieved by producing the antibody in a cell line exhibiting N-glycosylation deficiency. Wright et al., J Immunol. 1 60 (7): 3393-402 (1998). In some embodiments, the amino acid residue that interacts with the oligosaccharide attached to the N-glycosylation site of the constant region is mutated to reduce the binding affinity to FcyRI. For example, F241, V264, D265 of human IgG3 can be mutated. See, Lund et al., J. Immunology 157: 4963-4969 (1996). In some embodiments, the effector function is reduced by modifying regions such as 233-236, 297, and / or 327-331 of human IgG as described in WO 99/58572 and Armor et al., Molecular Immunology 40: 585 -593 (2003); Reddy et al., J. Immunology 164: 925-1933 (2000). The antibodies described in PCT WO 99/58572 and Armor et al. Comprise, in addition to a binding domain directed to the target molecule, an effector domain having an amino acid sequence substantially homologous to all or part of a region constant of a human immunoglobulin heavy chain. These antibodies have the ability to bind to the target molecule without triggering significant complement-dependent lysis or target-mediated destruction of the target. In some embodiments, the effector domain exhibits reduced affinity for FcyRI, FcyRIIa, and FcyRIII. In some modalities, the effector domain is able to join specific to FcRn and / or FcyRI lb. These are usually based on chimeric domains that are derived from two or more heavy chain CH2 domains of human immunoglobulin. Antibodies modified in this way are particularly suitable for use in a chronic treatment with antibodies, to avoid inflammatory reactions and other adverse reactions of conventional antibody treatment. In some embodiments, the constant region of the antibody heavy chain is a human IgG1 heavy chain with any of the following mutations: 1) A327A330P331 to G327S330S331; 2) E233L234L235G236 to P233V234A235 with G236 removed; 3) E233L234L235 to P233V234A235; 4) E233L234L235G236A327A330P331 to P233V234A235G327S330S331 with G236 removed; 5) E233L234L235A327A330P331 a P233V234A235G327S330S331; and 6) N297 to A297 or any other amino acid except N. In some embodiments, the heavy chain constant region of the antibody is a human IgG2 heavy chain with the following mutations: A330P331 to S330S331. In some embodiments, the constant region of the heavy chain of the antibody is a heavy chain of human IgG4 with any of the following mutations: E233F234L235G236 to P233V234A235 with G236 removed; E233F234L235 to P233V234A235; and S228L235 to P228E235. The constant region can also be modified to reduce complement activation. For example, activation of IgG antibody complement after binding of the C1 component of the complement may reduced by mutating amino acid residues in the constant region in a C1 binding motif (e.g., binding motif C1 q). It has been reported that a mutation to Ala for each of D270, K322, P329, P331 of human Ig1 significantly reduced the ability of the antibody to bind C1 and activate complement. For murine lgG2b, the binding motif C1 q constitutes residues E318, K320, and K322. Idusogle et al., J. Immunology 164: 4178-4184 (2000); Duncan et al., Nature 322: 738-740 (1988). The binding motif C1 q E318, K320, and K322 identified for murine IgG2b is believed to be common for other antibody isotypes. Duncan et al., Nature 322: 738-740 (1988). The binding activity of C1 q by IgG2b can be avoided by substituting any one of the three specified residues for a residue having an inappropriate functionality in its side chain. It is not necessary to replace only the ionic moieties with Ala to avoid the binding of C1 q. It is also possible to use other alkyl-substituted nonionic moieties, such as Gly, Lie, Leu, or Val, or non-polar aromatic moieties such as Phe, Tyr, Trp and Pro in place of any one of the three moieties to avoid binding of C1 q. In addition, it is also possible to use polar nonionic moieties such as Ser, Thr, Cys, and Met in place of residues 320 and 322, but not 3 8, to avoid the binding activity of C1 q. The invention also provides antibodies having a reduced effector function in which the antibody has a modified hinge region. The binding affinity of human IgG for its Fe receptors can be controlled by modifying the hinge region. Canfield et al., J. Exp. Med. 173: 1 483-1491 (1991); Hezareh and cois .. J. Viral. 75: 12161-12168 (2001); Redpath et al., Human Immunology 59: 720-727 (1998). The specific amino acid residues can be mutated or eliminated. The modified hinge region may comprise a complete hinge region derived from an antibody of a class or subclass of antibodies different from those of the CH1 domain. For example, the constant domain (CH1) of an IgG class antibody can bind to a hinge region of an IgG4 class antibody. Alternatively, the new hinge region may comprise part of a natural hinge or a repeat unit in which each unit of the repeat is derived from a natural hinge region. In some embodiments, the natural hinge region is altered by converting one or more cysteine moieties to a neutral moiety, such as alanine, or by converting moieties conveniently to cysteine moieties, see, for example, U.S. Patent No. 5,677,425 . Such alterations are made using chemical reactions of proteins recognized in the art and, preferably, genetic engineering techniques and as described herein. Polypeptides that specifically bind to a trkB receptor and fuse with a constant region of the heavy chain that have a reduced effector function can also be used for the methods described herein. An example of such fusion polypeptides is an immunoadhesin. See, for example, U.S. Patent No. 6, 153,189. Other procedures can also be used to prepare antibodies that have a reduced effector function known in the art. Antibodies and polypeptides with modified constant regions can be analyzed in one or more assays to assess the level of effector function reduction on biological activity compared to that of the initial antibody. For example, the ability of the antibody or polypeptide with an altered Fe region to bind to complement or to Fe receptors (e.g., Fe receptors of the microglia), or an altered hinge region using the assays described herein can be evaluated as well. as any assay recognized in the art. PCT document WO 99/58572; Armor et al., Molecular Immunology 40: 585-593 (2003); Reddy et al., J. Immunology 164: 1925-1933 (2000); Song et al., Infection and Immunity 70: 5 77-5184 (2002). Antibodies against agonists for trkB can be prepared using immunogens that express one or more extracellular domains for trkB. An example of an immunogen is cells with high expression for trkB, which can be obtained as described herein. Another example of an immunogen that can be used is a soluble protein (such as a trkB immunoadhesin) that contains the extracellular domain or a portion of the extracellular domain of the trkB receptor. The route and schedule of immunization of the host animal generally conforms to established and conventional techniques for the stimulation and production of antibodies, as further described herein. The general techniques for Production of human and murine antibodies are known in the art and are described herein. It is contemplated that any mammalian subject that includes humans or their cells that produce antibodies can be engineered to serve as the basis for the production of mammalian hybridoma cell lines, including human. Usually, the host animal is inoculated intraperitoneally with an amount of immunogen, which includes those described herein. Hybridomas can be prepared from immortalized lymphocytes and myeloma cells using the somatic cell hybridization technique of Kohler, B. and Milstein, C. (1975) Nature 256: 495-497 or as modified Buck, DW and cois., (1982) In vitro, 18: 377-381. The available myeloma lines, including but not limited to X63-Ag8.653, and those from the Salk Institute, Cell Distribution Center, San Diego, Calif., USA, may be used. UU in hybridization. Generally, the technique involves fusing myeloma cells and lymphoid cells using a fusogen such as polyethylene glycol, or by electrical means notorious to those skilled in the art. After fusion, the cells are separated from the fusion medium and cultured in a selective culture medium, such as hypoxanthine-aminopterin-thymidine (HAT) medium, to eliminate unhybridized progenitor cells. Any of the means described herein, supplemented with or without serum, can be used to culture hybridomas secreting monoclonal antibodies. As an alternative to the cell fusion technique, EBV immortalized B lymphocytes can be used to produce the monoclonal antibodies against trkB the present invention. The hybridomas are expanded and subcloned, if desired, and the supernatants are analyzed for activity against the immunogens by standard immunoassay methods (e.g., radioimmunoassay, enzyme immunoassay, or fluorescence immunoassay). Hybridomas that can be used as a source of antibodies encompass all derivatives, progeny cells of the parent hybridomas that produce monoclonal antibodies specific for trkB, or a portion thereof. Hybridomas producing said antibodies can be cultured in vitro or in vivo using known methods. Monoclonal antibodies can be isolated from the culture medium or body fluids, by conventional immunoglobulin purification procedures such as ammonium sulfate precipitation, gel electrophoresis, dialysis, chromatography, and ultrafiltration, if desired. Undesired activity, if any, can be eliminated, for example, by passing the preparation over absorbers formed by the immunogen bound to a solid phase and eluting or releasing the desired antibodies from the immunogen. Immunization of a host animal with a trkB receptor of human or other species, or a fragment of the trkB receptor of a human or other species, or the trkB receptor of a human or other species, or a fragment containing the sequence of a minoacid diana conjugated to a protein that is immunogenic in the species to be immunized, for example, keyhole limpet hemocyanin, serum albumin, bovine thyroglobulin or soybean trypsin inhibitor using a bifunctional or derivatizing agent, for example, maleimidobenzoyl sulfosuccinimide ester (conjugation through cysteine residues), N- hydroxysuccinimide (via lysine residues), glutaraldehyde, succinic anhydride, SOCI2 or R1 N = C = NR, where R and R1 are different alkyl groups can provide a population of antibodies (e.g., monoclonal antibodies). Another example of an immunogen is cells with high expression for trkB, which can be obtained by recombinant means or by isolating or enriching the cells from a natural source expressing a high level for trkB. These cells can be of human or other animal origin, and can be used as an immunogen as isolated directly or can be processed in such a way as to enhance or enrich the immunogenic capacity, or expression for trkB (of a dtrkB fragment). Said processing includes, but is not limited to, the treatment of the cells or their fragments with agents designed to increase their stability or immunogenic capacity, such as, for example, formaldehyde, ethanol, acetone and / or various acids. In addition, or before or after said treatment, the cells can be processed to enrich the concentration of the desired immunogen, in this case trkB or a fragment thereof. These processing steps may include membrane fractionation techniques, which are notorious in the art. If desired, the antibody (monoclonal or polyclonal) against trkB of interest can be sequenced and the polynucleotide sequence can then be cloned into the vector for expression or propagation. The sequence encoding the antibody of interest can be maintained in a vector of a host cell and the host cell can then be expanded and frozen for later use. Alternatively, the polynucleotide sequence can be used for genetic manipulation to "humanize" the antibody or to improve the affinity, or other characteristics of the antibody. For example, the constant region can be designed to look more like human constant regions to avoid immune responses if the antibody is used in clinical trials and treatments in humans. It may be desirable to genetically engineer the antibody sequence to obtain a greater affinity for the trkB receptor and a higher efficiency to activate the trkB receptor. It will be obvious to one of skill in the art that one or more changes of polynucleotides can be made in the antibody against trkB and still maintain their ability to bind from the extracellular domain to trkB or the epitopes to trkB. There are four general steps to humanize a monoclonal antibody. These are: (1) to determine the nucleotide sequence and predicted amino acid sequence of the light and heavy variable domains of the initial antibody (2) to design the humanized antibody, i.e. to decide which structural region of the antibody to use during the humanization process (3) the methodology / techniques of real humanization and (4) the transfection and expression of the humanized antibody. See, for example, U.S. Patent Nos. 4,816,567; 5,807,715; 5,866,692; 6.331, 415; 5,530,101; 5,693,761; 5,693,762; 5,585,089; 6,180,370; and 6,548,640. For example, the constant region can be designed to look more like human constant regions to avoid immune responses if the antibody is used in clinical trials and treatments in humans. See, for example, U.S. Patent Nos. 5,997,867 and 5,866,692. A number of "humanized" antibody molecules comprising an antigen-binding site derived from a non-human immunoglobulin have been described, which include chimeric antibodies having modified rodent or rodent V regions and their associated complementarity determining regions ( CDR) fused to human constant domains. See, for example, Wintery cois. Nature 349: 293-299 (1991), Lobuglio et al. Proc. Nat. Acad. Sci. USA 86: 4220-4224 (1989), Shaw et al. J Immunol. 138: 4534-4538 (1987), and Brown et al. Cancer Res. 47: 3577-3583 (1987). Other references describe rodent CDRs grafted onto a supporting human framework (FR) prior to fusion with a suitable human antibody constant domain. See, for example, Riechmann et al. Nature 332: 323-327 (1988), Verhoeyan et al. Science 239: 1534-1536 (1988), and Jones et al. Nature 321: 522-525 (1986). Another reference describes rodent CDRs supported by rodent structural regions modified by recombination. See, for example, European Patent Publication No. 519,596. These "humanized" molecules are designed to minimize an unwanted immune response towards rodent antibody molecules against human being that limits the duration and efficacy of the therapeutic applications of those residues in human receptors. The constant region of the antibody can be designed in such a way that it is immunologically inert, for example that it does not trigger a complement-mediated lysis or stimulate antibody-dependent cell-mediated cytotoxicity (ADCC). In other embodiments, the constant region is modified as described in Eur. J. Immunol. (1999) 29: 2613-2624; PCT application No. PCT / GB99 / 01441; and / or British patent application No. 9809951, 8. See, for example, in PCT / GB99 / 01441; British Patent Application No. 9809951, 8. Other methods for humanizing antibodies that can also be used are described in Daugherty et al. Nucí Acids Res. 19: 2471-2476 (1991) and in United States Patent Nos. 6,180,377; 6,054,297; 5,997,867; 5,866,692; 6,210,671; 6,350,861; and PCT publication No. WO 01/27160. In yet another alternative, fully human antibodies can be obtained using commercially available mice that have been designed to express specific human immunoglobulin proteins. Transgenic animals that are designed to produce a more desirable immune response (e.g., fully human antibodies) or more robust to generate humanized or human antibodies can also be used. Examples of such technology are Xenomouse ™ from Abgenix, Inc. (Fremont, CA) and HuMAb-Mouse® and TC Meda ™ Mouse ™, Inc. (Phnceton, NJ). In an alternative, the antibodies can be prepared by recombinant means and expressed using any method known in the art. In another alternative, antibodies can be prepared by recombinant means by bacteriophage display technology. See, for example, U.S. Patent Nos. 5,565,332; 5,580,717; 5,733,743 and 6,265,150; and Winter and co., Annu. Rev. Immunol. 12: 433-455 (1994). Alternatively, the bacteriophage display technology (McCafferty et al., Nature 348: 552-553 (1990)) can be used to produce human antibodies and antibody fragments in vitro from repertoires of variable domain genes (V). Immunoglobulins from immunized donors. According to this technique, the V-domain genes of the antibody are cloned in frame or in a major or minor envelope protein gene of a filamentous bacteriophage, such as M 3 or fd and are presented as functional antibody fragments on the surface of the bacteriophage particle. Because the filamentous particle contains a single-stranded DNA copy of the bacteriophage genome, selections based on the functional properties of the antibody also result in the selection of the gene encoding the antibody that exhibits those properties. Thus, the bacteriophage mimics some of the properties of the B lymphocyte. The presentation in bacteriophages can be done in a variety of formats; for a review see, for example, Johnson, Kevin S. and Chiswell, David J., Current Opinion in Structural Biology 3: 564-571 (1993). May Several sources of V gene segments are used for bacteriophage presentation. Clackson and cois. , Nature 352: 624-628 (1991) isolated a diverse set of antibodies against oxazolone from a small collection by randomly combining V genes derived from the spleens of immunized mice. A repertoire of V genes from non-immunized human donors can be constructed and antibodies can be isolated against a diverse set of antigens (including autoantigens) essentially following the techniques described by Mark et al., J. Mol. Biol. 222: 581-597 (1991), or Griffith et al., EMBO J. 12: 725-734 (1993). In a natural immune response, the antibody genes accumulate mutations at a high rate (somatic hypermutation). Some of the changes introduced will confer a greater affinity and the B lymphocytes that present superficial affinity immunoglobulins of high affinity preferentially replicate and differentiate during the subsequent exposure to the antigen. This natural process can be imitated using the technique known as "chain shuffling" Marks, and cois., Biotechnol. 10: 779-783 (1992)). In this procedure, the affinity of the "primary" human antibodies obtained by presentation in bacteriophages can be improved by sequentially substituting the genes of the V region of the heavy and light chain with repertoires of natural variants (repertoires) of the V domain genes obtained. from non-immunized donors. This technique makes it possible to produce antibodies and antibody fragments with affinities in the pM-nM range. A strategy to form antibody repertoires in bacteriophages very broad (also known as "the mother of all collections") has been described by Waterhouse and cois. , Nucí. Acids Res; 21: 2265-2266 (1993). The shuffling of genes can also be used to derive human antibodies from rodent antibodies, where the human antibody has affinities and specificities similar to the initial rodent antibody. According to this procedure, which is also called "epitope stamping", the V domain of the heavy or light chain of the rodent antibodies obtained by the bacteriophage presentation technique is replaced by a repertoire of genes from the V domain human, creating rodent chimeras and human being. The selection with antigens produces the isolation of human variable regions capable of restoring a functional antigen binding site, that is, the epitope governs (seals) the chosen partner. When the process is repeated to replace the remaining rodent domain V, a human antibody is obtained (see PCT Publication No. WO 93/06213, published April 1, 1993). In contrast to the traditional humanization of rodent antibodies by CDR grafting, this technique provides completely human antibodies, which has no ctural regions or CDR residues of rodent origin. It is obvious that although the above description refers to human antibodies, the general principles that are described are applicable to the tailor-made design of antibodies to be used, for example, in dogs, cats, primates, equines and bovines. The antibody can be a bispecific antibody, a Monoclonal antibody that presents binding specificities for at least two different antigens, can be prepared using the antibodies described herein. Methods for preparing bispecific antibodies are known in the art (see, for example, Suresh et al., 1986, Methods in Enzymology 121: 210). Traditionally, the recombinant production of bispecific antibodies was based on the coexpression of two heavy chain-immunoglobulin light chain pairs, where the two heavy chains have different specificities (Millstein and Cuello, 983, Nature 305: 537-539). According to one tegy a tegy of preparing bispecific antibodies, variable domains of antibodies with the desired binding specificities (antibody and antigen combining sites) are fused to the constant domain sequences of the immunoglobulins. The fusion preferably is with an immunoglobulin heavy chain constant domain, comprising at least part of the hinge, CH2 and CH3 regions. It is preferred to have the first constant region of the heavy chain (CH1), which contains the site necessary for the binding of the light chain, present in at least one of the fusions. The DNAs encoding immunoglobulin heavy chain fusions and, if desired, the immunoglobulin light chain are inserted into separate expression vectors and cotransfected to a suitable host organism. This provides greater flexibility to adjust the mutual proportions of the three polypeptide fragments in modalities in which proportions unequal of the three polypeptide chains that are used in conction provide optimal performances. However, it is possible to insert coding sequences for two or all three polypeptide chains in an expression vector when the expression of at least two polypeptide chains in equal proportions produces high yields or when the proportions are of no particular importance. In one tegy, bispecific antibodies are composed of a hybrid immunoglobulin heavy chain, with a first specificity of binding in one arm and a pair of heavy chain and light chain of hybrid immunoglobulin (which provides a second binding specificity) in the other arm. This asymmetric cture, with an immunoglobulin light chain only in the middle of the bispecific molecule, facilitates the separation of the desired bispecific compound from the unwanted immunoglobulin chain combinations. This strategy is described in PCT publication No. WO 94/04690. Heteroconjugate antibodies, comprising two covalently linked antibodies, are also within the scope of the invention. Such antibodies have been used to target cells of the immune system against unwanted cells (U.S. Patent No. 4,676,980), and for the treatment of HIV infection (PCT Publications No. WO 91/00360 and WO 92/200313; and EP 03089). Heteroconjugate antibodies can be prepared using any convenient crosslinking method. The agents and techniques of cross-linking are well known in the art, and are described in U.S. Patent No. 4,676,980. Antibodies can be prepared recombinantly by first isolating the antibodies prepared from host animals, obtaining the gene sequence and using the gene sequence to express the antibody recombinantly in host cells (e.g., CHO cells). Another method that can be employed is to express the antibody sequence in plants (eg, tobacco), transgenic milk or other organisms. Methods for expressing antibodies recombinantly in plants or milk have been described. See, for example, Peeters et al. (2001) Vaccine 19: 2756; Looberg, N. and D. Huszar (1995) Int. Rev. Immunol 1 3: 65; and Pollock and cois. (1999) J Immunol Methods 231: 147. Methods for preparing antibody derivatives, eg, humanized, single-chain, etc. they are known in the art. Chimeric or hybrid antibodies can also be prepared in vitro using known methods of chemical reactions of protein synthesis, including those using crosslinking agents. For example, immunotoxins can be constructed using a disulfide exchange reaction or forming a thioether linkage. Examples of reagents suitable for this purpose include iminothiolate and methyl-4-mercaptobutyrimidate. Fv chain fragments can also be produced, as described in Iliades et al., 1997, FEBS Letters, 409: 437-441. He coupling said single-stranded fragments using various linkers is described in Kortt et al., 1997, Protein Engineering, 10: 423-433. A variety of techniques for the recombinant production and manipulation of antibodies is well known in the art. The antibodies can be modified as described in PCT Publication No. WO 99/58572, published November 18, 1999. These antibodies comprise, in addition to a binding domain directed to the target molecule, an effector domain having an amino acid sequence substantially homologous to all or part of of a constant domain of a human immunoglobulin heavy chain. These antibodies have the ability to bind to the target molecule without triggering significant complement-dependent lysis or cell-mediated destruction of the target. Preferably, the effector domain has the ability to specifically bind to FcRn and / or FcvRllb. These are usually based on chimeric domains derived from two or more human immunoglobulin heavy chain domains CH2. It is preferred to use the antibodies modified in this way in the chronic treatment with antibodies, to avoid inflammation reactions and other adverse reactions of the conventional treatment with antibodies. Antibodies prepared either by immunization of a host animal, or recombinantly should display one or more of the activities of the agonist for trkB that are described herein.

Immunoassay and flow cytometry screening techniques such as fluorescence cell screening (FACS) can also be employed to isolate antibodies that are specific for trkB. The antibodies can bind to many different vehicles. The vehicles can be active and / or inert. Examples of notorious vehicles include polypropylene, polystyrene, polyethylene, dextran, nylon, amylases, glass, natural and modified celluloses, polyacrylamides, random and magnetite. The nature of the vehicle can be soluble or insoluble for the purposes of the invention. Those skilled in the art will know of other suitable vehicles to bind antibodies, or will be able to discern them using routine experimentation. The DNA encoding the antibodies against agonists for trkB can be sequenced, as is known in the art. Generally, the monoclonal antibody is easily isolated and sequenced using conventional procedures (e.g., using oligonucleotide probes that are capable of binding specifically to genes encoding the heavy and light chains of monoclonal antibodies). Hybridoma cells serve as the preferred source of said cDNA. Once isolated, the DNA can be introduced into expression vectors (such as expression vectors that are described in PCT publication no. WO 87/04462), which are then transferred to host cells such as E. coli cells, cells Simian COS, Chinese hamster ovarian cells (CHO), myeloma cells that do not produce other immunoglobulin proteins, obtaining the synthesis of monoclonal antibodies in the recombinant host cells. See, for example, PCT publication No. WO 87/04462. The DNA can also be modified, for example, by substituting the coding sequence for constant domains of human heavy and light chain instead of the homologous murine sequences, Morrison et al., Proc. Nat. Acad. Sci. 81: 6851 (1984), or by covalently joining the immunoglobulin coding sequence to all or part of the coding sequence for a polypeptide other than an immunoglobulin. Thus "chimeric" or "hybrid" antibodies having the binding specificity of a monoclonal antibody against trkB of this document are prepared. The DNA encoding the antibody against agonist for trkB (such as an antigen-binding fragment thereof) can also be used for the administration and expression of an antibody against agonist for trkB in a desired cell, as described herein. . The techniques of DNA administration are further described herein. Antibodies against trkB can be characterized using procedures well known in the art. For example, one method is to identify the epitope to which they bind which includes resolving the crystal structure of an antibody and antigen complex, competition assays, gene fragment expression assays, and synthetic peptide-based assays, as described, by example, in Chapter 1 1 of Harlow and Lane, Using Antibodies, A Laboratory Manual, Coid Spring Harbor Laboratory Press, Cold Spring Harbor, New York, 1999. In a further example, epitope mapping can be used to determine the sequence to which an antibody binds to trkB. Epitope mapping is commercially available from several sources, for example, Pepscan Systems (Edelhertweg 15,821 9 PH Lelystad, The Netherlands). The epitope can be a linear epitope, that is, contained in a single stretch of amino acids, or a conformational epitope formed by a three-dimensional interaction of amino acids, which must not necessarily be contained in a single stretch. Peptides of varying lengths (eg, at least 4-6 amino acids in length) can be isolated or synthesized (eg, recombinantly) and used for binding assays with an antibody against trkB. In another example, the epitope to which the antibody against trkB binds can be determined in a systematic screening using superimposed peptides that are derived from the extracellular sequence for trkB and determining binding by the antibody against trkB. In accordance with the gene fragment expression assays, the open reading frame encoding trkB is fragmented either randomly or by specific genetic constructs and the reactivity of the fragments expressed for trkB with the antibody to be analyzed is determined. Gene fragments can be produced, for example, by PCR and then transcribed and translated into protein in vitro, in the presence of radioactive amino acids. The binding of the antibody to the radiolabelled trkB fragments is then determined by immunoprecipitation and gel electrophoresis. Certain epitopes can also be identified using large collections of random peptide sequences that occur on the surface of bacteriophage particles (collections of bacteriophages). Yet another method that can be used to characterize an antibody to trkB is to use competition assays with other antibodies known to bind to the same antigen, i.e., the extracellular domain for trkB to determine if the antibody against trkB binds to the same epitope than other antibodies. Competition trials are well known to those skilled in the art. Examples of antibodies useful in competition assays include the following: antibodies 6.1.2, 6.4.1, 2345, 2349, 2.5.1, 2344, 2248, 2250, 2253, and 2256. See PCT publication No. WO 01/98361. Epitope mapping can also be performed using domain exchange mutants as described in PCT Publication No. WO 01/98361. Generally, this strategy is useful for antibodies against trkB that do not show a significant cross-reaction with trkA or trkC. Domain exchange mutants for trkB can be prepared by substituting the extracellular domains for trkB by the corresponding domains of trkC or trkA. The binding of each antibody against trkB agonist to various domain exchange mutants can be evaluated and compared to binding to wild-type (native) trkB using ELISA or other methods known in the art. In another strategy, a scan with alanine can be performed. The individual antigen residues, the trkB receptor, are systematically mutated to another amino acid (usually alanine) and the effect of the changes is evaluated by analyzing the ability of the modified trkB to bind to the antibody using ELISA or other methods known in the art.

BDNF Polypeptides The agonist for trkB that was used in the methods of the invention includes BDNF polypeptides. As used herein, "BDNF polypeptide" includes the natural mature protein (interchangeably called "BDNF") such as mature human BDNF which is shown in U.S. Patent No. 5,180,820 and natural sequence variants of BDNF amino acids; amino acid sequence variants of BDNF; peptide fragments of mature BDNF (such as human) and said amino acid sequence variants; and modified forms of mature BDNF and said variants of amino acid sequences and peptide fragments in which the polypeptide or peptide has been covalently modified by substitution with a residue other than a natural amino acid, insofar as the variant of the amino acid sequence, the peptide fragment and the modified form thereof show one or more biological activities of an agonist for trkB and / or natural mature BDNF protein. TrkB agonists also include fusion proteins and conjugates comprising any of the BDNF polypeptide embodiments described herein, for example, a BDNF polypeptide conjugated or fused to a rest which increases the half-life, such as PEG or a peptide. Vanants of amino acid sequences, peptide fragments (including fragment variants), or modified forms thereof considered do not include NGF, NT-4/5, or NT-3 of any animal species. The BDNF polypeptides include one or more of the embodiments described herein. For example, the BDNF polypeptide comprises a natural sequence with one or more amino acid insertions, deletions, or substitutions. In some embodiments, the BDNF polypeptide is a mammalian BDNF polypeptide that can be a wild-type mammalian BDNF, or BDNF polypeptide derived from a natural mammalian BDNF and having a sequence that does not correspond to any part of a natural BDNF that does not be of mammal. In some embodiments, the BDNF polypeptide is a human BDNF polypeptide that can be a natural human BDNF, or a BDNF polypeptide that is derived from a natural human BDNF and has a sequence that does not correspond to any part of a natural BDNF that does not be human The BDNF polypeptides, which include variants, peptide fragments, modified forms of BDNF polypeptides (including natural BDNF), fusion protein and conjugate of the invention are characterized by any (one or more) of the following characteristics: (a) binding to a trkB receiver; (b) joining a trkB receptor and activating the biological activity (s) for trkB and / or one or more downstream routes mediated by the (s) signaling function (s) for trkB; (c) binding to a trkB receptor and increasing body weight and / or food intake in a primate when administered peripherally; (d) binding to a trkB receptor and treating, preventing, reversing or ameliorating one or more symptoms of cachexia or unwanted weight loss in a primate when administered peripherally; (e) binding to a trkB receptor and treating, preventing, reversing or ameliorating one or more symptoms of anorexia nervosa in a primate when administered peripherally; (f) binding to a trkB receptor and treating, preventing, reversing or ameliorating one or more symptoms of opioid-induced emesis in a mammal when administered, peripherally: (g) promoting dimerization and activation of the trkB receptor; and (h) increase neuronal survival dependent on the trkB receptor and / or neurite growth. Thus all BDNF polypeptides (including variants, fragments and modified forms) are functional as described above. The biological activity of the variants can be analyzed in vitro and in vivo using methods known in the art and methods described herein. The BDNF polypeptides may have enhanced activity or reduced activity compared to a natural BDNF protein. In some modalities, functonally equivalent variants have at least about 50%, 60%, 70%, 75%, 80%, 85%, 90%, or 95% activity compared to the native BDNF protein from which the polypeptide is derived BDNF with respect to one or more of the biological assays described previously (or that are known in the art). In some embodiments, functionally equivalent variants have an EC50 (half the effective minimum concentration) of less than about either 0.01 nM, 0.1 nM, 1 nM, 10 nM or 100 nM in activation of the trkB receptor in vitro (eg example tests described in Example 6, and in documents US 2005/0209148 and PCT WO 2005/082401). The amino acid sequence variants of BDNF include polypeptides having an amino acid sequence that differs from native BDNF by insertion, deletion and / or substitution of one or more amino acid residues of the natural BDNF sequence (eg, mature human BDNF that shown in Table 1). The amino acid sequence variants will generally be at least about 65%, 70%, 75%, 80%, 85%. 90%, 95%, 96%, 97%, 98%, or 99% identical to any natural BDNF (such as mature human BDNF). In some embodiments, the variant is at least approximately 70% identical to the amino acid sequence of mature human BDNF. In some embodiments, the variant is at least approximately 85% identical to the amino acid sequence of mature human BDNF. In some embodiments, the variant is at least approximately 90% identical to the amino acid sequence of mature human BDNF. In some embodiments, the variant is at least approximately 95% identical to the amino acid sequence of mature human BDNF. Such variations that, for example, convert BDNF to NGF, BDNF or NT-3 are not included in the scope of this invention. Thus, although the site for introducing a variation of the amino acid sequence is predetermined, the nature of the mutation per se need not be predetermined. For example, to optimize the functioning of a mutation at a given site, a wing scan or random mutagenesis is performed on the codon or target region and the BDNF variants are screened to determine the desired activity. Deletions of amino acid sequences generally vary in the range from about 1 to 30 residues, more preferably, from about 1 to 10 residues, and are usually contiguous. Deletions can be introduced in regions of low homology between BDNF, NGF, NT-3 and NT-4/5 to modify the activity of BDNF. Deletions of BDNF in areas of substantial homology with NT-4/5, NT-3, and NGF may have a greater likelihood of modifying the biological activity of BDNF more significantly. The number of consecutive deletions can be selected so as to preserve the tertiary structure of BDNF in the affected domain, for example, beta-folded sheet or alpha helix. Inserts in the amino acid sequences include fusions at the amino and / or carboxyl termini ranging in length from a moiety to polypeptides containing one thousand or more residues, as well as intrasequence insertions of a single or multiple amino acid residues. The intrasequence insertions (i.e., insertions in the mature BDNF sequence) can generally vary from about 1 to 10 residues, more preferably, from 1 to 5, most preferably 1 to 3. An example of a terminal insertion includes the fusion of a heterologous signal sequence at the N-terminus at the N-terminus of the BDNF molecule to facilitate the secretion of mature BDNF by the recombinant host. Said signals will generally be homologous to the host cell that is intended and include STII or Ipp for E. coli, alpha factor for yeast and viral signals such as herpes gD for mammalian cells. Other insertions include fusion of a polypeptide at the N or C terminus of BDNF. Another group of variants includes those in which at least one amino acid residue of BDNF has been removed, and preferably only one, and a different residue is inserted in its place. One example is the replacement of arginine and lysine by other amino acids to make BDNF resistant to proteolysis by serine proteases, thus creating a variant of BDNF that is more stable. The sites of greatest interest for substitution mutagenesis include sites in which the amino acids found in BDNF, NGF, NT-3, and NT-4/5 are substantially different in terms of volume, charge, or hydrophobicity of the side chain. , but in which there is also a high degree of homology at the selected site among animal analogues of NGF, NT-3, and NT-4/5 (for example among all animal NGFs, all NT-3 animals and all animal BDNFs). This analysis will highlight the remains that may be involved in the differentiation of the activity of the trophic factors and, therefore, the variants in these sites may affect these activities. Other sites of interest are those in which the remains are identical between BDNF, NGF, NT-3, and NT-4/5 of all animal species. This degree of conformation suggests the importance of achieving a common biological activity to the four factors. For example, substitution of one or more amino acids includes conservative substitutions. The methods of making conservative substitutions are known in the art. For example, wing (A) can be replaced by val, leu, ile, preferably by val; arg (R) can be substituted by lys, gln, asn, preferably by lys; asn (N) can be replaced by gln, his, lys, arg, preferably by gln; asp (D) can be replaced by glu; cys (C) can be replaced by being; gln (O) can be replaced by asn; glu (E) can be replaced by asp; gly (G) can be replaced by pro; his (H) can be replaced by asn, gln, lys, arg; preferably by arg; ile (I) can be replaced by leu, val, met, ala, phe, norleucine, preferably by leu; leu (L) can be replaced by norleucine, ile, val, met; to; phe, preferably by ile; lys (K) can be replaced by arg; gln, asn, preferably by arg; met (M) can be replaced by leu; phe; ile, - preferably by leu; phe (F) can be replaced by leu, val, ile, ala, preferably by leu; pro (P) can be replaced by gly; being (S) can be replaced by thr; thr (T) can be replaced by being; trp (W) can be substituted by tyr, tyr (Y) can be substituted by trp, phe, thr, ser, preferably by phe; val (V) can be replaced by ile; leu; met; phe, wing; norleucine, preferably by leu. Substantial modifications can be achieved by selecting substitutions that differ significantly in their effect on the maintaining (a) the skeletal structure of the polypeptide in the area of substitution, for example, in the form of sheet or helical conformation, (b) the loading or hydrophobicity of the molecule at the target site, or (c) the volume of the side chain. The natural remains are divided into groups based on the common properties of the side chains (some of these may correspond to different functional groups): (1) hydrophobic: norleucine, met, ala, val, leu, ile; (2) neutral hydrophilic: cys, ser, thr; (3) acids: asp, glu; (4) basic: asn, gln, his, lys, arg; (5) residues that influence the orientation of the chain: gly, pro; and (6) aromatics: trp, tyr, phe. Non-conservative substitutions will involve exchanging a member of one of these classes for another. The variants of the amino acid sequences of BDNF may be natural or may be prepared synthetically, such as by introducing appropriate nucleotide changes into a previously isolated BDNF DNA or by in vitro synthesis of the polypeptide variant that is desired. As indicated above, said variants may comprise deletions, or insertions or substitutions, of one or more residues to minoacids within the amino acid sequence of mature BDNF (eg, the sequence shown in Table 1). Any combination of deletion, insertion, and substitution is performed to obtain a variant of amino acid sequence of BDNF, with the proviso that the polypeptide variant possesses a desired characteristic. The amino acid changes can also produce additional modifications of BDNF after expression in recombinant hosts, for example by introducing or moving glycosylation sites, or by introducing membrane anchoring sequences (see, for example, PCT WO 89/01041). In some embodiments, the BDNF polypeptide comprises an amino acid sequence encoded by a nucleic acid that hybridizes under stringent conditions to a nucleic acid sequence that encodes mature human BDNF. The polynucleotide variants also, alternatively, may be substantially homologous to a native gene, or to a portion or complement thereof. Said polynucleotide variants can hybridize under moderately restrictive conditions to a natural DNA sequence encoding the polypeptide (or a complementary sequence). Those of ordinary skill in the art will appreciate that, as a result of the degeneracy of the genetic code, there are many nucleotide sequences that encode a polypeptide as described herein. Some polynucleotide hedges have minimal homology to the nucleotide sequence of any native gene. However, polynucleotides that vary due to differences in the use of the codons are contemplated specifically by the present invention. In addition, the alleles of the genes that comprise the sequences of polynucleotides that are provided herein are within the scope of the present invention. Alleles are endogenous genes that are altered as a result of one or more mutations, such as deletions, additions and / or nucleotide substitutions. The resulting mRNA and protein may have, but not necessarily, an altered structure or function. Alleles can be identified using standard techniques (such as hybridization, amplification and / or comparison between database sequences). The agonists for trkB that are used in the methods of the invention also include fusion proteins comprising the amino acid sequence of BDNF (eg, human BDNF shown in Table 1) or a functional peptide fragment thereof. Biologically active BDNF polypeptides can be fused with sequences, such as sequences that enhance immunological reactivity, facilitate coupling of the polypeptide to a support or a carrier, or facilitate folding and / or purification (e.g., sequences encoding epitopes such as Myc, HA derived from influenza virus hemagglutinin, His-6, FLAG). These sequences can be fused to a BDNF polypeptide at the N-terminus or at the C-terminus. In addition, the protein or polynucleotide can be fused with other polypeptides that increase its function or specify its location in the cell, such as a secretion sequence. Methods for producing recombinant fusion proteins that are described above are known in the art. The protein Fusion recombinant can be produced, folded and isolated by well-known procedures in the art. The BDNF polypeptides described herein may be modified to increase their half-lives in an individual. For example, the BDNF polypeptide can be pegylated to reduce systemic clearance with minimal loss of biological activity. The invention also provides compositions (including pharmaceutical compositions) comprising a BDNF polypeptide linked to a PEG molecule. In some embodiments, the PEG molecule is linked to the BDNF polypeptide through a reversible linkage. The half-life of a PEGylated BDNF polypeptide can be increased by more than about 2 times, 5 times, 10 times, 20 times and 30 times compared to the half-life of the non-pegylated BDNF polypeptide. The PEG polymers can be linked to various functional groups of the BDNF polypeptide using methods known in the art. See, for example, Roberts and cois. Advanced Drug Delivery Reviews 54: 459-416 (2002); Sakane and cois. Pharm. Res. 14: 1086-91 (1991). The PEG can be linked to the following functional groups of the polypeptide: amino groups, carboxyl groups, modified or natural N-termini, amino groups and thiol groups. In some embodiments, one or more surface amino acid residues are modified with PEG molecules. The PEG molecules can be of various sizes (for example, ranging from about 2 to 40 kDa). PEG molecules linked to the polypeptide BDNF can have a molecular weight of approximately 2,000, 10,000, 15,000, 20,000, 25,000, 30,000, 35,000, 40,000 Da. The PEG molecule can be a single or branched chain. To link PEG and the BDNF polypeptide, a PEG derivative having a functional group at one or both ends can be used. The functional group is chosen based on the type of reactive group available in the BDNF polypeptide. Methods for linking binding derivatives to polypeptides are known in the art. Roberts et al., Advanced Drug Delivery Reviews 54: 459-476 (2002). The link between the BDNF polypeptide and the PEG can also be such that it can be cleaved or naturally degraded (reversible or degradable link) in an individual which can improve the half-life but minimize the loss of activity. The PEG binding site in the BDNF polypeptide can also be created by mutating the surface residues to an amino acid residue having a group that reactions with PEG, such as, a cysteine. The BDNF polypeptide can be produced by recombinant means, i.e., by expression of the nucleic acid encoding the BDNF polypeptide in recombinant cell culture, and, optionally with purification of the variant of the cell culture polypeptide, for example, by activity bioassay. of the variant or by absorption in an immunoaffinity column comprising polyclonal rabbit antibodies against BDNF (which bind to at least one immune epitope of the variant that is also present in native BDNF). The fragments Small peptides, of the order of 40 residues or less, are prepared conveniently by in vitro procedures. The DNA encoding the BDNF polypeptide can be cloned into an expression vector to express the protein in a host cell. Examples of nucleic acids encoding the BDNF polypeptide are described in U.S. Patent Application Publication No. 2003/0203383. The DNA encoding the BDNF polypeptide in its mature form can be linked at its amino terminus to a secretion signal. This secretion signal is preferably the presequence of BDNF that normally directs the secretion of BDNF in human cells in vivo. However, suitable secretion signals also include signals from other animal BDNFs, NGF, NT-2, or NT-3 signals, viral signals or signals from segregated polypeptides of the same or related species. Any host cell (such as E. coli) can be used to express the protein or polypeptide. The expressed BDNF polypeptide can be purified. The BDNF polypeptide can be recovered from the culture medium in the form of a secreted protein, although it can also be recovered from lysates of host cells when it is directly expressed without a secretion signal. Protein purification procedures known in the art can be used. The methods for producing the BDNF polypeptide and purifying the expressed BDNF polypeptide are known in the art. B DNF polypeptide can be expressed in E. coli and folded according to procedures known in the art. Mature human BDNF can also be obtained commercially (for example, in R &D Systems). The methods for generating and producing NT-4/5 polypeptides can also be used to generate and produce BDNF polypeptides.

Identification of agonists for trkB Agonists for trkB (such as antibodies) can be identified using methods recognized in the art, which include one or more of the following methods. For example, the receptor kinase activation assay (KIRA) that is described in U.S. Patent Nos. 5,766,863 and 5,891,650 can be used. This ELISA-type assay is suitable for qualitative or quantitative measurements of kinase activation by measuring the autophosphorylation of the kinase domain of a receptor tyrosine kinase protein (rPTK, eg, trk receptor), as well as for the identification and characterization of agonists or Potential antagonists of a selected rPTK. The first step of the assay involves the phosphorylation of the kinase domain of a receptor kinase, in the present case a trkB receptor, in which the receptor is present on the cell membrane of a eukaryotic cell. The receptor can be an endogenous receptor or a nucleic acid encoding the receptor, or a receptor construct that can transform the cell. Usually, a first solid phase (for example, a well of a first test plate) is coated with a substantially homogeneous population of said cells (usually a mammalian cell line) so that the cells adhere to the solid phase. Often, the cells are adherent and therefore adhere naturally to the first solid phase. If a "receptor construct" is used, it usually comprises a fusion of a receptor kinase and a marker polypeptide. The marker polypeptide is recognized by the capture agent, often a capture antibody, in the ELISA part of the assay. An analyte, such as a candidate agonist, is then added to the wells having the adherent cells, such that the receptor tyrosine kinase (eg, the trkB receptor) is exposed (or contacted) with the analyte. This assay allows the identification of agonist ligands for the receptor tyrosine kinase of interest (eg trkB). Upon exposure to the analyte, the adherent cells are solubilized using a lysis buffer (which has solubilizing detergent in it) and gentle agitation, thus releasing the cell lysate that can be subjected to the ELISA part of the assay directly, without the need to concentrate or clarify the cell lysate. The cell lysate thus prepared is then ready to undergo the ELISA step of the assay. As a first step of the ELISA step, a second solid phase (usually one well of an ELISA microtiter plate) is coated with a capture agent (often a capture antibody) that specifically binds to the tyrosine kinase receptor or, in the case of a receptor construct, the marker polypeptide. The coating of the second solid phase is carried out in such a way that the capture agent adheres to the second solid phase. The agent of capture is generally a monoclonal antibody, but as described in the examples herein, polyclonal antibodies or other agents can also be used. The obtained cell lysate is then exposed or contacted with the adherent capture agent so that the receptor or receptor construct adheres (ie captured) to the second solid phase. A washing step is then carried out, so that the unbound cell lysate is removed, leaving the receptor or receptor construction captured. The receptor or receptor construct is adherent or captured after it is exposed or contacted with an antibody against phosphotyrosine that identifies the tyrosine phosphorylated residues of the receptor tyrosine kinase. In the preferred embodiment, the antibody against phosphotyrosine is conjugated (directly or indirectly) with an enzyme that catalyzes a color change of a reagent with non-radioactive color. Accordingly, the phosphorylation of the receptor can be measured by a subsequent color change of the reagent. The enzyme can be bound to the antibody against phosphotyrosine directly or a conjugation molecule (eg, biotin) can be conjugated to the antibody against phosphotyrosine and the enzyme can subsequently be linked to the antibody against phosphotyrosine by the conjugation molecule. Finally, the binding of the antibody against phosphotyrosine to the recipient or construction of captured receptor is measured, for example, by changing the color of the color reagent. After initial identification, the agonist activity of a candidate (eg, a monoclonal antibody against trkB) can be confirmed additionally and refined by known bioassays to analyze the biological activities that are sought. For example, the ability of a candidate to act as an agonist for trkB in the PC12 neurite growth assay can be analyzed using PC12 cells transfected with full length trkB (Jiah et al., Cell Signal 8: 365-70, 1996) . This assay measures the growth of neurite ramifications in rat pheochromocytoma cells (PC12) in response to stimulation by appropriate ligands. These cells express endogenous trkA and therefore respond to NGF. However, they do not express endogenous trkB and therefore are transfected with an expression construct for trkB to elicit a response against agonists for trkB. After incubating the transfected cells with the candidate, the growth of the neurites is measured, and for example, cells with neurites that exceed 2 times the diameter of the cell are counted. Candidates (such as antibodies against trkB) that stimulate neurite growth in transfected PC1 2 cells demonstrate agonist activity for trkB. Activation for trkB can also be determined using various specific neurons at specific stages of embryonic development. Adequately selected neurons may depend on activation for trkB for survival and thus it is possible to determine activation for trkB by following the survival of these neurons in vitro. The addition of candidates for primary cultures of appropriate neurons will lead to the survival of these neurons for a period of time of at least several days if the candidates activate trkB. This allows determining the ability of the candidate (such as an antibody against trkB) to activate trkB. In one example of this type of assay, the nodose ganglion of an E15 mouse embryo is dissected, dissociated and the resulting neurons plated in a tissue plate at low density. The candidate antibodies are then added to the medium and the plates are incubated for 24-48 hours. After this time, the survival of the neurons is evaluated by any of a variety of procedures. Samples that received an agonist will usually have a higher survival rate than samples that receive a control antibody, and this allows to determine the presence of an agonist. See, for example, Buchman and cois. (1993) Development 1 18 (3): 989-1001. The agonists for trkB can be identified by their ability to activate downstream signaling in a variety of cell types that express trkB either naturally or after transfection of DNA encoding trkB. This trkB can be human trkB or from another mammal (such as a rodent or primate). The downstream signaling cascade can be detected by changes that occur in a variety of biochemical or physiological parameters of the cell expressing trkB, such as the level of protein expression or protein phosphorylation of proteins or changes in metabolic state or of cell growth (including neuronal survival and / or neurite growth, as described herein). Procedures to detect biochemical substances or parameters Relevant physiological techniques are known in the art.

V. Kits The invention also provides kits for use in the present methods. Kits of the invention include one or more containers comprising a purified trkB agonist (e.g., a natural NT-4/5 or BDNF and an antibody against an agonist for trkB) and instructions for use in accordance with any of the methods of the invention described herein. In general, these instructions comprise a description of the administration of the agonist for trkB to treat a disease, such as cachexia, anorexia nervosa, and opioid-induced emesis, according to any of the procedures described herein. The kit may further comprise a description of the selection of an individual suitable to treat based on identifying whether that individual has the disease and the stage of the disease. The instructions that refer to the use of agonist for trkB generally include information regarding the dose, posology and route of administration for the intended treatment. The containers can be single dose, bulk containers (eg multiple dose containers) or subunit doses. The instructions provided in the kits of the invention are usually instructions written on a label or leaflet (for example, a sheet of paper included in the kit), but they are also acceptable instructions for reading by means of an apparatus (for example, instructions contained in an optical storage disk). The label or package insert indicates that the composition is used to treat a disease described herein (such as cachexia, anorexia nervosa, and opioid-induced emesis). Instructions for practicing any of the procedures described in this document may be provided. The kits of this invention are in a suitable container. Suitable containers include, but are not limited to, vials, boxes, jars, flexible packaging (e.g., sealed Mylar or plastic bags), and the like. Also contemplated are packages for use in combination with a specific device, such as an inhaler, nasal delivery device (e.g., an atomizer), or an infusion device such as a minipump. A kit may have a sterile access port (for example the container may be an intravenous solution bag or a vial having a plug pierceable by a hypodermic injection needle). The package may also have a sterile access port (for example, the package may be a bag or vial with intravenous solution having a plug pierceable by a hypodermic injection needle). At least one active agent of the composition is an agonist for trkB. The package may further comprise a second pharmaceutically active agent. The kits may optionally provide additional components such as buffers and information for their interpretation.

Typically, the kit comprises a package and a label or package insert (s) on or associated with the package. The following Examples are provided to illustrate, but not to limit the invention. EXAMPLES EXAMPLE 1 Daily infusion of NT-4/5 produced weight gain and hyperphagia in obese baboons Three obese female baboons (body weight varying between 20-30 kg) received an intravenous infusion (IV) of human NT-4/5 at 2 mg / kg once a day from day 1 to day 24. Three other female baboons Obese (body weight that varied between 20-30 kg) received an IV infusion of vehicle (PBS) once a day from day 1 to day 24. Food intake was measured daily for the first 45 days. Animals were weighed once a week for the first 53 days and then followed up on day 81 and day 109 respectively. Figure 1 shows the effect of the daily infusion of NT-4/5 on the body weight of obese baboons. As shown in Figure 1, the body weight of the group treated with NT-4/5 increased significantly compared to the group treated with vehicle; and body weight of the group treated with NT-4/5 returned to the level of the group treated with vehicle for the day 81 The data indicated that daily infusion with NT-4/5 produced a prolonged but reversible weight gain in obese baboons. Figure 2 shows the effect of daily infusion with NT-4/5 on food intake in obese baboons. As shown in Figure 2, the food intake of the group treated with NT-4/5 increased significantly compared to the group treated with vehicle; and the food intake of the group treated with NT-4/5 returned to the level of the group treated with vehicle for day 33. The data indicated that the daily infusion with NT-4/5 produced a reversible hyperphagia in obese baboons.

EXAMPLE 2 Infusion twice a week of NT-4/5 produced weight gain but not hyperphagia in obese baboons Three obese female baboons (body weight varying between -30 kg) received an intravenous (IV) infusion of human NT-4/5 at 2 mg / kg once a day from day 1 to day 39. Three other obese female baboons (body weight varying between 20-30 kg) received a vehicle IV infusion (PBS) twice a week from day 1 to day 39. Food intake was measured daily for the first 55 days. Animals were weighed daily for the first 66 days and then followed up on day 94 and day 122 respectively. Figure 3 shows the effect of the infusion twice at the Week of NT-4/5 on the body weight of obese baboons. As shown in Figure 3, the body weight of the group treated with NT-4/5 increased significantly compared to the group treated with vehicle; and body weight of the group treated with NT-4/5 returned to the level of the group treated with vehicle for day 94. The data indicated that infusion twice a week with NT-4/5 produced a prolonged but reversible weight gain in obese baboons. Figure 4 shows the effect of infusion twice a week with NT-4/5 on food intake in obese baboons. As shown in Figure 4, the twice-weekly infusion of NT-4/5 did not significantly change the food intake in obese baboons according to the two-way ANOVA analysis. Bonferroni post hoc analyzes did not show a significant difference between pairs between the group treated with NT-4/5 (black triangles) and the group treated with vehicle (white squares).

EXAMPLE 3 Daily infusion of NT-4/5 produced increased body weight and hyperphagia in thin macaques Three thin female macaques (body weight varied between 3-5 kg) received an intravenous (IV) infusion of human NT-4/5 at 2 mg / kg per day from day 1 to day 31. Three thin female macaques (body weight varied between 3-5 kg) received an IV infusion of pegylated NT-4/5 (pegylated NT4-G1 S) at 0.6 mg / kg infusion once a week from day 1 to day 31; Pegylated NT-4/5 was generated by introducing a glycine mutation from position 1 of the mature human NT-4/5 sequence to serine and attaching PEG to the first amino acid of serine as described in Example 7 of the publication U.S. Patent Application No. 2005/0209148 and PCT WO 2005/082401. Three other thin female macaques (body weight varied between 3-5 kg) received vehicle IV infusion (PBS) once a day from day 1 to day 31. Food intake was measured daily for the first 50 days. Animals were weighed once a week until day 50. Figure 5 shows the effect of daily infusion of NT-4/5 on body weight in thin female macaques. As shown in Figure 5, the body weight of the group treated daily with NT-4/5, but not the one treated once a week with pegylated NT-4/5, increased significantly compared with the group treated with vehicle. The body weight of the group treated with NT-4/5 had not completely returned to the level of the vehicle-treated group. The data indicated that the daily infusion with NT-4/5 caused an increase in body weight in the thin macaques. Figure 6 shows the effect of daily infusion of NT-4/5 on food intake in thin female macaques. As shown in Figure 6, the food intake of the group treated daily with NT-4/5, but not the one treated once a week with NT-4/5 pegylated, increased significantly compared to the group treated with vehicle. The food intake of the group treated with NT-4/5 had not completely returned to the level of the group treated with vehicle on day 38. The data indicated that the daily infusion with NT-4/5 caused reversible hyperphagia in the thin macaques. The effect of NT-4/5 and pegylated NT-4/5 on body weight was also evaluated by subcutaneous administration. Three thin female macaques (body weight varied between 3-5 kg) received a subcutaneous (SC) injection of human NT-4/5 at 2 mg / kg per day from day 1 to day 21. Three thin female macaques (body weight varied between 3-5 kg) received a SC injection of NT-4/5 pegylated at 1 mg / kg once a day from day 1 to day 21. Three other thin female macaques (body weight varied between 3-5 kg) received a SC vehicle injection (PBS) once a day from day 1 to day 21. The animals were weighed once a week until day 21. Figure 7 shows the effect of daily SC injection of NT-4/5 and pegylated NT-4/5 on body weight in thin female macaques. As shown in the Figure. 7, the body weight of the group treated with NT-4/5 increased significantly compared to the group treated with vehicle. In addition, also the body weight of the group treated with pegylated NT-4/5 also increased significantly compared to the group treated with vehicle.

EXAMPLE 4 Daily subcutaneous injection of NT-4/5 showed no significant effect on body weight and food intake in NZW rabbits Five male New Zealand white rabbits and five female rabbits (body weight varied between 3-4 kg) received a subcutaneous (SC) injection of human NT-4/5 at 2 mg / kg per day from day 1 to day 15. Other five male New Zealand white rabbits and five female rabbits (body weight varied between 3-4 kg) received a SC vehicle injection (PBS) once a day from day 1 to day 15. Food intake was measured daily during the first 15 days. The animals were weighed once a week until day 15. No statistically significant differences were observed between the group treated with NT-4/5 and the group treated with vehicle for body weight or food intake. Comparisons were made between male rabbits treated with NT-4/5 and male rabbits treated with vehicle, and between female rabbits treated with NT-4/5 and female rabbits treated with vehicle.

EXAMPLE 5 A single injection of NT-4/5 did not cause vomiting but can reduce the vomiting induced by morphine in ferrets The effect of NT-4/5 on emesis in adult female ferrets with body weight of approximately 1 kg (Marshall Farm, CT) was studied. An emetic agent (0.05 mg / kg of 6-glucuronide morphine, M6G) was administered subcutaneously as a positive control to establish the initial level before administration of NT-4/5. An increasing dose of NT-4/5 (0.1, 1, or 10 mg / kg) was injected subcutaneously to 6 ferrets (for each dose) only to analyze if NT-4/5 could cause any adverse effects such as retching or vomiting. In addition, two doses, 1 mg / kg and 10 mg / kg, of NT-4/5 were administered 10 minutes before M6G to analyze whether NT-4/5 could suppress the emesis induced by M6G. The animals were returned to their cage and observed to determine the latency, the number of retching and vomiting during a period of 60 minutes after the injection. As shown in Figure 8, a single injection of 0.1, 1 or 10 mg / kg of NT-4/5 alone did not cause vomiting in the ferrets, whereas a single SC injection of 0.05 mg / kg of M6G induced the emesis effectively. Both 1 mg / kg and 10 mg / kg of NT-4/5 significantly reduced the vomiting induced by M6G in ferrets. To analyze the activation site for trkB that could be responsible for the effect against the emesis of the SC injection of NT-4/5 in the ferrets, the activation by c-Fos for trkB in the brainstem of the ferret was analyzed. A single dose of 10 mg / kg of NT-4/5 was injected subcutaneously, followed by intravenous 10 mg / kg of cisplatin 5 minutes later, to five female ferrets. A single dose of vehicle injection was administered, followed by cisplastine 5 minutes later to four other female ferrets as a negative control. Animals were sacrificed 1 hour later by pentobarbital sodium (65 mg / kg ip), fixed by intracardiac perfusion with 1 l / kg of PBS followed by 1 l / kg of 4% paraformaldehyde at pH 7.3. Sections of brainstem were cut at 30 pm and slices were incubated in 10% normal donkey serum (NOS) diluted in 0.1% Triton X-00 (in PBS) for 1 hour followed by incubation in sheep antibody against Fos (1: 1, 000, OA-1 1 -0824, Genosys Biotechnologies, Cambridge; United Kingdom) in PBS with 0.1% Triton X-100 and 10% NOS for 48 hours at 4 ° C. The sections were washed in PBS and then incubated in biotinylated secondary antibody solution against sheep IgG for 60 minutes at room temperature. Staining was revealed using the avidin biotin complex technique (Vectastain Elite avidin-biotin complex (ABC) Kit, Vector). Briefly, the sections were incubated in ABC reagent for 60 minutes at room temperature and then in a solution containing 3,3-diaminobenzidine (0.5 mg / ml) for 30-60 seconds. Then the brainstem cuts were mounted on slides to dry for 24 hours, dehydrated for 4 minutes each in ethanol at 50, 70, 95, and 100% and then rinsed in xylene, after which they were mounted and they observed. The borders of nuclei and sub-nuclei of the nucleus tractus solitarius (NTS) were evaluated in adjacent sections stained with cresyl violet. The number of immunoreactive neuronal nuclei with c-Fos was determined bilaterally for the postrema area, doral vagal nucleus (DMNX), and all the sub-nuclei of the NTS at three levels by the rostrocaudal extension of the dorsal vagus complex (DVC); 0.5-1 .0 mm rostral and 0.5 mm flow to the obex and in the obex. Three cuts were counted per level per animal and averaged. The data were compared using ANOVA with Tukey post hoc test (Prism, GraphPad Software, San Diego, CA). Treatment with NT-4/5 significantly increased the number of positive nuclei for c-Fos in the postrema area compared to the animals injected with vehicle (Figure 9A, P = 0.0009, Student's t test). On the other hand, treatment with NT-4/5 significantly decreased the number of nuclei positive for c-Fos in the dorsal nucleus of the vagus compared with animals injected with vehicle (Figure 9B, P = 0.0047, Student's t-test). ). On the other hand, treatment with NT-4/5 did not significantly alter the number of positive nuclei for c-Fos in other nuclei of the brainstem, which includes the multiple sub-nuclei of the NTS as well as the paraventricular nuclei of the hypothalamus. The postrema area, unlike most other areas of the brain, is outside the blood-brain barrier and has full access to circulating macromolecules (for a recent example, see Yang and Ferguson, 2003, Regul Pept. (1 -3): 9-1 7). The induction of c-Fos is a early known immediate event of activation for trkB by its ligands such as BDNF and NT-4/5 (Ip et al 1993, J. Neurosci 3 (8): 3394-405 and Marsh et al 1993, J. Neurosci 13 (10): 4281-92). These data together suggest that the postrema area constitutes at least in part a reliable form of "peripherally accessible" target of NT-4/5 or other trkB agonists administered systemically. The reduction of the expression of c-Fos in the dorsal nucleus of the vagus (Figure 9B) may reflect a partial attenuation of the vomiting circuit by pretreatment with NT-4/5.

EXAMPLE 6 Generation and screening of antibodies against agonists for trkB Immunization to generate monoclonal agonists against Trk8 agonists: A single Balb / C mouse was injected 5 times with a usual schedule 8 pg of extracellular domain for trkB as antigen. The extracellular domain for His-tagged trkB (residues 31 -430) was expressed using the pTriEx-2 Hygro vector (Novagen, Madison Wl) in 293 cells. The extracellular domain for trkB was purified using Ni-NTA resin according to the manufacturer's instructions (Qiagen, Valencia, CA). For the first 4 injections, the antigen was prepared by mixing human trkB with adjuvant system RIBI and alum. In total, 8 pg of antigen was administered by injection into the neck, the foot pads and IP, approximately every 3 days during the course of 1 1 days. On day 13, the mouse was sacrificed and the spleen was extracted. The lymphocytes were fused with 8653 cells preparing hybridoma clones. The clones were allowed to reproduce and then screened as positive against TrkB by ELISA screening with an ELISA for both human and rat TrkB. Screening for TrkB antibody ELISA: supernatants from expanding hybridoma clones were screened according to their ability to bind both human and rat trkB. The assays were performed in 96-well plates coated overnight with 100 μ? 0.5 g / ml of human or rat TrkB-Fc fusion protein. The excess reagents were washed from the wells between each stage with PBS containing 0.05% Tween-20. The plates were then blocked with phosphate buffered saline (PBS) containing 0.5% BSA. The supernatant was added to the plates and incubated at temperature environment for 2 hours. Goat anti-mouse Fe antibody conjugated to horseradish peroxidase (HRP) was added to bind mouse antibodies bound to TrkB. Then tetramethylbenzidine was added as a substrate for HRP to detect the amount of mouse antibody present in the supernatant. The reaction was terminated and the amount of relative antibody was quantified by reading the absorbance at 450 nm. It was shown that fifty antibodies were positive in the ELISA assay. Among these antibodies, five were further analyzed and shown to have agonist activity. See Table 2 below. Test by KIRA: This test was used to sift the antibodies to receptor tyrosine kinase for human trkB. Sadick and cois. (1997) Experimental Cell Research 234 (2): 354-61. Using a stable cell line transfected with GD-labeled trkB, murine antibodies purified from the hybridoma clones were analyzed for their ability to activate the surface receptor of the cells similar to the activation observed with the natural ligands, BDNF and NT-4 / 5. Natural ligands induced autophosphorylation of the kinase domain of the trkB receptor. After exposing the cells to various antibody concentrations, they were lysed and an ELISA was performed to detect phosphorylation of the trkB receptor. The EC50 (shown in Table 2 below and in Figure 10) was determined for each putative agonist for trkB and compared to that of the natural ligand: NT-4/5. Survival assay of nodose neurons in E15: Nodes ganglion neurons obtained from E15 embryos were maintained by BDNF, so that at saturation concentrations of the neurotrophic factor, survival was close to 100% at 48 hours in culture. In the absence of BDNF, less than 5% of the neurons survived 48 hours. Therefore, the survival of the nodose neurons in E15 is a sensitive assay to evaluate the agonist activity of the antibodies against trkB, that is, the antibodies against agonists will stimulate the survival of the nodule neurons of E15. Pregnant Swiss Webster female mice were sacrificed at the same time by inhalation by C02. The horns were removed uterine embryos were extracted and embryonic stage E15. The nodose ganglia were dissected and then trypsinized, mechanically dissociated and plated at a density of 200-300 cells per well in serum-free medium defined in 96-well plates coated with poly-L-ornithine and laminite. The agonist activity of the antibodies against TrkB was evaluated in a dose dependent manner in triplicate using human BDNF as reference. After 48 hours the cells in culture were subjected to an automated immunocytochemistry protocol performed in a work station with Biomek FX liquids (Seckman Coulter). The protocol included fixation (4% formaldehyde, 5% sucrose, PBS), permeabilization (0.3% Triton X-100 in PBS), blocking non-specific binding sites (5% normal goat serum, 0.1% BSA, PBS) and sequential incubation with primary and secondary antibodies to detect neurons. A polyclonal rabbit antibody was used against the protein gene product 9.5 (PGP9.5, Chemicon), which is a neuronal phenotypic marker established as a primary antibody. Goat Alexa Fluor 488 antibody against rabbit (Molecular Probes) was used as a secondary reagent together with the nuclear dye Hoechst 33342 (Molecular Probes) to label the nuclei of all the cells present in the culture. Image acquisition and image analysis were performed on a Discovery-1 / Genll Imager (Universal Imaging Corporation). The images were acquired automatically at two wavelengths for Alexa fluor 488 and Hoechst 33342, using nuclear staining as a reference point, since it is present in all Wells for the imager's autofocus image system. Appropriate targets were selected and the number of sites from which images were obtained per well so that the entire surface of the well was covered. The analysis of automated images was adjusted to count the number of neurons present in each well after 48 hours in culture based on their specific staining with the antibody against PGP9.5. Careful application of image thresholds and selectivity filters based on morphology and fluorescence produced an accurate count of the neurons per well. The EC50 (shown in Table 2 below and in Figure 11) were determined for each antibody against putative trkB agonist and compared with those of the natural ligand. Table 2 below shows the five antibodies against trkB identified and their activities on the survival of mouse neurons and the phosphorylation activity on human trkB.

TABLE 2 Intracranial antibodies against agonists for trkB in mice: Retired male reproductive C57B6 mice (aged 8-12 months) were obtained from Charles River Laboratories (Hollister facilities) and allowed to acclimate in an environment of controlled temperature and humidity, with a 12-hour light and dark cycle with access to food and water ad libitum for at least 5 days before injection. Each mouse was anesthetized with isoflurane, to cut a section of hair over the skull. The mouse was placed on the stereotaxic surgery instrument (Kopt model 900), anesthetized and given heat with an electric blanket with medium adjustment. Betadine was applied over the shaved portion of the skull to sterilize the region. A longitudinal incision of approximately 1 cm in length was made on the skull that began just behind the ears towards the eyes. The skull was discovered and a circular space approximately 1 cm in diameter was cleaned from the surface of the skull with a cotton swab to remove all connective tissue. The surface cleaned with a cotton swab immersed in 30% hydrogen peroxide, to expose the storm. Using the tip of the drill as a probe to measure the depth of the skull, the skull was adjusted horizontally and vertically to make sure it was level before drilling. The depth deviation (with zero level in the temporal) was minimized from 0.5 mm medium compared to 0.5 mm lateral, as well as 0.5 mm anterior compared to 0.5 mm posterior, with a difference of ± 0.05 mm. According to the mouse brain atlas (Frankiin, KBJ and Paxinos, G. The Mouse Brain in Stereotaxic Coordinators, Academic Press, San Diego, 1997), the coordinates for a single lateral intrahypothalamic injection were as follows: 1.30 mm posterior to from the temporary; (1.5 mm from the median line, depth 5.70 mm from the surface of the skull (in the temporal) A small hole was made through the skull avoiding touching the brain The drill was replaced by a bevelled 26 gauge needle to a Hamilton syringe (model 84851) and returned to the same coordinates, 2 μ of compound was injected into the lateral hypothalamus incrementally for 2 minutes, the needle was held in this position 30 seconds after the injection, then After a further 30 seconds, the needle was lifted 1 mm, the needle was removed completely 30 seconds later, the incision was then closed and sutured with 2-9 mm staples (Autoclip, Braintree Scientific, Inc. , Braintree, MA). The injection was performed on day 0. Body weight and food intake were monitored daily until day 15. As shown in Figure 12A and Figure 12B, the Intracranial injections of 18H6 and 36D1 antibodies at the specified dose significantly reduced body weight and food intake in the mice. The control IgG antibody and 23B8, administered at the specified dose, did not significantly affect either the intake of 5 foods or the body weight. A two-way ANOVA with Bonferroni post hoc was used for the statistical analysis. This indicates that antibodies against agonists for trkB have an effect on body weight and food intake qualitatively similar to NT-4/5, a natural agonist for trkB, when injected directly into the CNS. I 0 EXAMPLE 7 Peripheral injection of antibody against agonist for trkB caused a higher food intake and body weight in monkeys thin adult female macaques (weighing 3-5 kg at baseline) received intravenous injections of mouse monoclonal antibody against agonist 38B8 and the other three animals received vehicle twice a week. Food consumption was controlled daily and body weight once a week. Statistical analyzes were performed using 0 PRISM (GraphPad Software Inc., San Diego, CA). All data and graphs are expressed as mean ± standard error of the mean (ETM). The data were analyzed by a 2-way ANOVA with post hoc Dunnet tests (* P <0.05, ** P <0.01, *** P <0.001).

Monkeys treated twice a week with injections of 5 mg / kg antibody 38B8 against agonist for trkB showed a 40% increase in cumulative food intake (Figure 13A) and an increase of 10% by weight (Figure 13B) in 2 weeks, which indicates that the specific activation of the trkB receptor tyrosine kinase acts as a mediator of food intake, higher caloric intake and greater body weight. It is understood that the examples and embodiments described herein are merely illustrative and that they will suggest various modifications or changes in view thereof to those skilled in the art and should be included in the spirit and scope of this patent application.

Claims (10)

NOVELTY OF THE INVENTION CLAIMS

1 .- The use of NT-4/5 or a pharmaceutically acceptable salt thereof in the manufacture of a medicament useful for treating cachexia, anorexia nervosa, unwanted weight loss or emesis induced by opioids in a human, wherein the drug is adapted to be peripherally administrable.

2. The use as claimed in claim 1, wherein the medicament is useful for treating cachexia or unwanted weight loss and the human being has a body mass index less than approximately 25.0 kg / m2, 24.0 kg. / m2, 2

3.0 kg / m2, 22.0 kg / m2, 21 .0 kg / m2, 20 kg / m2, 19.0 kg / m2 and 18.5 kg / m2. 3. The use as claimed in claim 1 or 2, wherein the unwanted weight loss is associated with aging.

4. - The use as claimed in the subdivision 1, wherein the drug is useful for treating anorexia nervosa and the human being has a body mass index less than approximately either 18.5 kg / m2, 1 7.5 kg / m2 or 16.5 kg / m2.

5. The use of an agonist for trkB or a pharmaceutically acceptable salt thereof in the manufacture of a medicament useful for treating cachexia, anorexia nervosa, unwanted weight loss or induced emesis by opioids in a human being, wherein the medicament is adapted to be peripherally administrable.

6. The use as recited in claim 5, wherein the agonist for trkB is selective for trkB.

7. The use as claimed in claim 5 or 6, wherein the agonist for trkB is an antibody against the agonist for trkB.

8. The use as claimed in any of claims 5-7, wherein the medicament is useful for treating cachexia or unwanted weight loss and the human being has a body mass index of less than approximately 25.0 kg / m2, 24.0 kg / m2, 23.0 kg / m2, 22.0 kg / m2, 21 .0 kg / m2, 20 kg / m2, 1

9.0 kg / m2 and 18.5 kg / m2. 9. - The use as claimed in any of claims 5-8, wherein unwanted weight loss is associated with aging.

10. - The use as claimed in any of claims 5-7, wherein the medicament is useful for treating anorexia nervosa and the human being has a body mass index less than about any of 18.5 Kg / m2, 1 7.5 Kg / m2 or 16.5 Kg / m2.