WO2025248110A1

WO2025248110A1 - An oncolytic herpes simplex virus (hsv) and an anti-pd-1 antibody for use in treating braf mutant melanoma

Info

Publication number: WO2025248110A1
Application number: PCT/EP2025/065033
Authority: WO
Inventors: Robert Stuart Coffin
Original assignee: Replimune Ltd
Current assignee: Replimune Ltd
Priority date: 2024-05-31
Filing date: 2025-05-30
Publication date: 2025-12-04
Anticipated expiration: 2026-11-30

Abstract

A method of treating BRAF mutant melanoma in a patient, including in a patient who is BRAF targeted therapy naïve, comprising administering a therapeutically effective amount of an oncolytic herpes simplex virus (HSV) and an anti-PD-1 antibody to the patient, wherein the oncolytic HSV comprises genes encoding (i) a glycoprotein from gibbon ape leukemia virus (GALV) from which the R peptide has been deleted (GALVR-) and (ii) GM-GSF.

Description

TREATMENT

Field

The disclosure relates to the treatment of melanoma using an oncolytic virus.

Melanoma may originate from a number of different anatomic sites including skin, mucosal surfaces, conjunctiva, and uveal structures. Several melanoma- specific antigens have been identified, and patients often have tumor infiltrates of CD8+ T-cells specific for melanoma antigens, although they show blunted responses and signs of exhaustion, possibly due to the action of regulatory T-cells (Tregs) and other mechanisms of immune suppression.

For patients without visceral disease (Stage IIIB/C and Stage IVMla), 5-year survival rates are ~ 30% to 50%. Patients with visceral metastatic disease face a more dismal prognosis with 5-year survival rates of 16% (Mlb) and 5% (Mlc). Advanced melanoma spreads in an unpredictable fashion with widespread metastasis to any organ site but often to skin, lung, brain, liver, or small bowel.

Since most cases of melanoma are diagnosed at an early stage and are curable with surgery alone, standard treatment options for Stage I to resectable Stage III are surgery with or without lymph node dissection. For advanced disease, treatment options were limited until recent developments and approvals. Since 2011, 8 agents, including 4 immunotherapies (ipilimumab, pembrolizumab, nivolumab, and talimogene laherparepvec) and 4 molecular targeted therapies (vemurafenib, dabrafenib, trametinib, and cobemetinib), have received regulatory approval in the USA. As a consequence, systemic treatment strategies have undergone dramatic changes. Immunotherapy and kinase inhibitors are the backbone of systemic therapy. Chemotherapy is now a second-line treatment option.

Long-term results with immuno-oncology (1-0) agents and targeted therapies have provided evidence of durable survival for a substantial number of patients with cutaneous melanoma. However, more than half of patients treated with single-agent anti-PD-1 drugs have disease that does not respond to therapy (primary resistance), whereas others have disease that ultimately progresses later while on therapy (secondary resistance) (Ochoa and Joseph 2017). Despite the addition of an anti-CTLA-4 antibody to anti-PD-1 containing regimens, primary resistance is observed in 40% to 45% of patients, and secondary resistance occurs in roughly 30% to 40% of patients (Mooradian and Sullivan 2019). Given these results, considerable unmet need continues to exist.

At progression after treatment with anti-PD-1 therapy, several options may be available in BRAF wild-type or BRAF mutant melanoma patients who have previously received RAF and MEK inhibitors, including continued treatment with anti-PD-1 therapy, combination anti-PD-1 + anti-CLTA4 therapy, or chemotherapy. Retreatment with anti-PD- 1 therapy or chemotherapy has demonstrated overall response rates between 4% and 10% with a median overall survival (OS) of approximately 7 to 8 months (Larkin et al. 2018; Merck 2019; Goldinger et al. 2018; Kirchberger et al. 2016).

An FDA pooled analysis of 2624 melanoma patients receiving anti-PD- 1 therapy for metastatic melanoma reported that 3.6% (95/2624) experienced tumor shrinkage with continued treatment following initial disease progression (Beaver, Hazarika, Mulkey, Mushti, Chen, He, et al. 2018). Alternative analysis of the data suggest a higher response rate of 7% (Ribas, Kirkwood, and Flaherty 2018). These findings are in agreement with those of Hodi and colleagues, who reported response following progression in 6-7% (Hodi et al. 2016). Treatment with chemotherapy such as DTIC fared no better with a response rate of approximately 5%.

In patients with disease that is anti-CTLA-4 naive, ipilimumab may be an option post progression on anti-PD-1 therapy. An analysis of patients in the KEYNOTE 006 trial who received ipilimumab as the immediate line of therapy following disease progression on pembrolizumab reported a 15% response rate in 97 patients and a median survival of 13.6 months (Robert et al. 2019). Combination of ipilimumab with anti-PD-1 therapy following progression on single agent anti-PD-1 therapy has also been explored. A small multicenter retrospective study in advanced melanoma patients who were treated with nivolumab plus ipilimumab (n=37) or ipilimumab alone (n=47) after anti-PD-1 failure demonstrated response rates of 16% and 21%, respectively (Zimmer et al. 2017).

The development of effective immunotherapies for immune checkpoint inhibitor resistant disease is a pressing priority in oncology. Summary

Effective treatment of melanoma in patients who failed anti-PD- 1 therapy has been demonstrated using the combination of an oncolytic herpes simplex virus (HSV) and an anti-PD- 1 antibody.

The combination of the oncolytic HSV and the anti-PD- 1 antibody described herein provides improved treatment of cancer through the generation of improved tumor focused immune responses. The combination treatment provides clinically proven anti-tumor effects including immune-mediated effects on tumors which are not destroyed by oncolysis, such as non-injected tumors. The effective destruction of tumors, and effective long term anti-tumor vaccination prevents future relapse and improve overall survival.

The inventors have, in particular surprisingly demonstrated that the combined treatment of melanoma in patients with confirmed progression on prior anti-PD- 1 therapy show an on-target response, an objective response rate (ORR) of over 30% using Response Evaluation Criteria in Solid Tumors (RECIST) vl.l, with 100% of responses lasting more than six months, a median duration of response (DOR) of over 35 months and predominantly only grade 1/2 constitutional-type side effects.

Accordingly, provided is a method of treating melanoma in a patient who failed anti-PD- 1 therapy, e.g. confirmed progression on prior anti-PD- 1 therapy, comprising administering a therapeutically effective amount of an oncolytic herpes simplex virus (HSV) and an anti-PD- 1 antibody to the patient, wherein the oncolytic HSV comprises genes encoding (i) a glycoprotein from gibbon ape leukemia virus (GALV) from which the R peptide has been deleted (GALVR-) and (ii) GM-GSF, and wherein the method results in an overall response rate of greater than 30% analyzed by RECIST vl.l.

Also provided is a method of treating melanoma in a patient who failed anti-PD- 1 therapy, comprising administering a therapeutically effective amount of an oncolytic herpes simplex virus (HSV) and an anti-PD- 1 antibody to the patient, wherein the oncolytic HSV comprises genes encoding (i) a glycoprotein from gibbon ape leukemia virus (GALV) from which the R peptide has been deleted (GALVR-) and (ii) GM-GSF, and wherein the method results in a median duration of response measured from baseline to end of response for responding patients of greater than 35 months analyzed by RECIST vl.l.

Further provided is a method of treating melanoma in a patient who failed anti-PD- 1 therapy, comprising administering a therapeutically effective amount of an oncolytic herpes simplex virus (HSV) and an anti-PD-1 antibody to the patient, wherein the oncolytic HSV comprises genes encoding (i) a glycoprotein from gibbon ape leukemia virus (GALV) from which the R peptide has been deleted (GALVR-) and (ii) GM-GSF, and wherein the method results in a duration of response measured from baseline to end of response for responding patients of greater than 6 months analyzed by RECIST vl.l.

Additionally provided is a method of treating melanoma in a patient who failed anti-PD- 1 therapy, comprising administering a therapeutically effective amount of an oncolytic herpes simplex virus (HSV) and an anti-PD-1 antibody to the patient, wherein the oncolytic HSV comprises genes encoding (i) a glycoprotein from gibbon ape leukemia virus (GALV) from which the R peptide has been deleted (GALVR-) and (ii) GM-GSF, and wherein the treatment results in reduction in the size of at least one lesion by at least 30% compared to baseline.

In one aspect a method of treating melanoma in a patient who failed anti-PD-1 therapy, comprising administering a therapeutically effective amount of an oncolytic herpes simplex virus (HSV) and an anti-PD-1 antibody to the patient, wherein the oncolytic HSV comprises genes encoding (i) a glycoprotein from gibbon ape leukemia virus (GALV) from which the R peptide has been deleted (GALVR-) and (ii) GM-GSF, and wherein the treatment results in no adverse events above Grade 3 as determined by the Common Toxicity Criteria for Adverse Events (CTCAE).

Hence, the invention also provides an oncolytic herpes simplex virus (HSV) for use in a method of treating melanoma in a patient who has failed anti-PD- 1 therapy, wherein the oncolytic HSV comprises genes encoding (i) a glycoprotein from gibbon ape leukemia virus (GALV) from which the R peptide has been deleted (GALVR-) and (ii) GM-GSF, wherein the method further comprises administering an anti-PD-1 antibody to the patient, and wherein the method results in:

(a) an overall response rate (ORR) of greater than 30% analyzed by RECIST vl.l;

(b) a duration of response measured from baseline to end of response for responding patients of greater than 6 months analyzed by RECIST vl.l;

(c) a median duration of response measured from baseline to end of response for responding patients of greater than 35 months analyzed by RECIST vl.l;

(d) reduction in the size of at least one lesion by at least 30% compared to baseline; and/or

(e) no adverse events above Grade 3 as determined by the Common Toxicity

Criteria for Adverse Events (CTCAE). The invention also provides an anti-PD-1 antibody for use in a method of treating melanoma in a patient who has failed anti-PD- 1 therapy, wherein the method further comprises administering an oncolytic herpes simplex virus (HSV) to the patient, wherein the oncolytic HSV comprises genes encoding (i) a glycoprotein from gibbon ape leukemia virus (GALV) from which the R peptide has been deleted (GALVR-) and (ii) GM-GSF, and wherein the treatment method results in:

(a) an overall response rate (ORR) of greater than 30% analyzed by RECIST vl.l;

(b) a duration of response measured from baseline to end of response for responding patients of greater than 6 months analyzed by RECIST vl.l; and/or

(e) no adverse events above Grade 3 as determined by the Common Toxicity Criteria for Adverse Events (CTCAE).

The invention also provides an oncolytic herpes simplex virus (HSV) and an anti- PD-1 antibody for use in a method of treating melanoma in a patient who failed anti-PD-1 therapy, wherein the oncolytic HSV comprises genes encoding (i) a glycoprotein from gibbon ape leukemia virus (GALV) from which the R peptide has been deleted (GALVR-) and (ii) GM-GSF, and wherein the treatment method results in:

(a) an overall response rate (ORR) of greater than 30% analyzed by RECIST vl.l;

In another aspect, the invention provides a method of treating BRAF-mutated melanoma in a patient, comprising administering a therapeutically effective amount of an oncolytic herpes simplex virus (HSV) and an anti-PD-1 antibody to the patient, wherein the oncolytic HSV comprises genes encoding (i) a glycoprotein from gibbon ape leukemia virus (GALV) from which the R peptide has been deleted (GALVR-) and (ii) GM-GSF. The patient is preferably BRAF-targeted therapy naive.

The invention also provides an oncolytic herpes simplex virus (HSV) for use in a method of treating BRAF mutant melanoma in a patient, including in a patient who is BRAF targeted therapy naive, wherein the oncolytic HSV comprises genes encoding (i) a glycoprotein from gibbon ape leukemia virus (GALV) from which the R peptide has been deleted (GALVR-) and (ii) GM-GSF, wherein method further comprises administering an anti-PD- 1 antibody to the patient.

The invention also provides an anti-PD- 1 antibody for use in a method of treating BRAF mutant melanoma in a patient, including in a patient who is BRAF targeted therapy naive, wherein method further comprises administering an oncolytic herpes simplex virus (HSV) to the patient, wherein the oncolytic HSV comprises genes encoding (i) a glycoprotein from gibbon ape leukemia virus (GALV) from which the R peptide has been deleted (GALVR-) and (ii) GM-GSF.

The invention also provides an oncolytic herpes simplex virus (HSV) and an anti- PD- 1 antibody for use in a method of treating BRAF mutant melanoma in a patient, including in a patient who is BRAF targeted therapy naive, wherein the oncolytic HSV comprises genes encoding (i) a glycoprotein from gibbon ape leukemia virus (GALV) from which the R peptide has been deleted (GALVR-) and (ii) GM-GSF.

Brief description of the figures

Figure 1 is a schematic diagram of the design of the phase 1/2 multi-cohort clinical trial of RP1 alone or in combination with nivolumab in patients with anti-PD- 1-failed cutaneous melanoma. ^aDosing with nivolumab begins at dose 2 of RP1 (C2D15). ^bOption to reinitiate RP1 for 8 cycles if criteria are met.

Figure 2 shows images from a patient who received prior atezolizumab+cobimetinib, ipilimumab, SX682 (CXCR-inhibitor)+ atezolizumab, ipilimumab+nivolumab before taking part in the IGNYTE study. Responses were observed in un-injected distant and visceral tumors (white circled tumors), including healing of lytic bone lesions (increasing sclerosis & new internal bone formation were seen).

Figure 3 shows images from a patient who took part in the IGNYTE study. The patient had stage IVMlb BRAF-mutant disease which progressed having had treatment with nivolumab. Responses can be seen in un-injected distant and visceral tumors. Figure 4 shows the depth of response of the combined treatment with RP1 and nivolumab in melanoma patients who had failed anti-PD-1 therapy.

Figure 5 shows the duration of benefit of the combined treatment with RP1 and nivolumab in melanoma patients who had failed anti-PD-1 therapy.

Figure 6 shows the duration of response (time from baseline to end of response for responders) of the combined treatment with RP1 and nivolumab in melanoma patients who had failed anti-PD-1 therapy by investigator using mRECIST 1.1 (red line) vs. central review using RECIST 1.1 (blue line).

Figure 7 depicts the structure of the oncolytic virus RP1. RP1 is a modified version of HSV1 strain RH018A. The ICP34.5 and ICP47 genes are inactivated in RP1. The US11 gene is placed under the control of the ICP47 immediate early gene promoter by deletion of the ICP47 gene. An expression cassette is inserted into each of the two ICP34.5 gene loci. The expression cassette includes a gene encoding human GM-CSF under the control of a first promoter (Pl) in back to back orientation with a gene encoding GALV-R- under the control of a second promoter (P2). Each of the genes in the expression cassette is terminated with a polyA sequence (pAl and pA2). Pl is a CMV promoter. P2 is a RSV promoter.

Figure 8 shows the duration from response initiation of response (A) and the duration of clinical benefit from baseline (B) of the combined treatment with RP1 and nivolumab in melanoma patients who had failed anti-PD-1 therapy using mRECIST 1.1.

Figure 9 shows the change in size of individual injected (blue) and non-injected (red) lesions over time analysed using mRECIST vl.l.

Figure 10 shows images taken at baseline and at 9 months from a patient who took part in the IGNYTE study. The patient received prior adjuvant nivolumab followed by pembrolizumab as first line therapy before taking part in the IGNYTE study. The patient had stage IVMlc melanoma.

Figure 11 shows the probability of overall survival of patients over time. One-, two-, and three-year survival rates were 75.3%, 63.3%, and 54.8%, respectively. Median overall survival has not been reached.

Figure 12 shows the probability of ongoing response of responders with BRAF- mutated melanoma who have not received BRAF/MEK inhibitor therapy. The data were analysed by independent review using RECIST 1.1. Detailed description

Methods of Treatment/Medical Uses

The invention relates to the treatment of melanoma in patients who failed anti-PD- 1 therapy.

The invention also relates to the treatment of BRAF-mutated melanoma, including in patients who are BRAF targeted therapy naive.

The combination of an oncolytic HSV and an anti-PD- 1 antibody as disclosed herein may be independently administered to a subject in an amount that is compatible with the dosage composition that will be therapeutically effective. The oncolytic HSV and the anti-PD- 1 antibody as disclosed herein may be administered independently. The oncolytic HSV and the anti-PD- 1 antibody as disclosed herein may be administered concurrently. The oncolytic HSV and the anti-PD- 1 antibody as disclosed herein may be administered sequentially.

The administration of the virus of the disclosure is for a “therapeutic” purpose. As used herein, the term “therapeutic” or “treatment” includes any one or more of the following as its objective: the prevention of any metastasis or further metastasis occurring; the reduction or elimination of symptoms; the reduction or complete elimination of a tumor or cancer, an increase in the time to progression of the patient’s cancer; an increase in time to relapse following treatment; or an increase in survival time.

The melanoma may be a stage III or IV cancer. The stage III cancer may be stage Illb or inc. The stage IV cancer may be stage IVMla, IVMlb, IVMlc or IVMld.

The prior anti-PD- 1 therapy may comprise treatment with a PD-1 inhibitor or a PDL-1 inhibitor. The prior anti-PD- 1 therapy may comprise administering a PD-1 inhibitor as a single agent. The prior anti-PD- 1 therapy may comprise administering a PD- 1 inhibitor in combination with a CTLA-4 inhibitor. The PD- 1 inhibitor may be an anti- PD- 1 antibody. Examples of anti-PD- 1 antibodies include nivolumab, pembrolizumab, cemiplimab, atezolizumab, durvalumab, avelumab, tislelizumab, retifanlimab, dostarlimab, JTX-4014, spartalizumab, camrelizumab, sintilimab, toripalimab, retifanlimab (INCMGA00012), AMP-224, MEDI0680 (AMP-514), sasanlimab, budigalimab, ezabenlimab (BI 754091), and zimberelimab (AB122), see further below. The CTLA-4 inhibitor may be an anti-CTLA-4 antibody. Examples of anti-CTLA-4 antibodies include ipilimumab. The PD-1 inhibitor may be an anti-PDL-1 antibody. Examples of anti-PD-Ll antibodies include avelumab, durvalumab and atezolizumab. For example, the patient may have previously been treated with an anti-PD-1 antibody, such as nivolumab, pembrolizumab and cemiplimab.

The patient may be previously been treated with anti-PD- 1 therapy for at least 1 month, at least six weeks, at least 2 months, at least 3 months, at least 4 months, at least 5 months, at least 6 months, at least 7 months, at least 8 months, at least 9 months, at least 10 months, at least 11 months, at least 12 months, at least 18 months, or at least 24 months. For example, the patient may have previously been treated for at least 6 months with the anti-PD-1 antibody, such as nivolumab, pembrolizumab and cemiplimab.

The treatment is particularly effective in patients who have confirmed progression of tumor on or after anti-PD-1 therapy, e.g. as determined on at least 8 weeks of treatment with anti-PD-1 therapy. Tumor progression may be confirmed by the increase in size of a tumor, e.g. by imaging on consecutive MRI scans or by clinical assessment over time.

The treatment is effective in patients who received prior anti-PD- 1 therapy as first line therapy, or as adjuvant therapy.

The treatment is particularly effective in certain groups of patients, such as patients who have tumor with primary resistance to prior anti-PD-1 therapy, patients who have tumor with secondary resistance to prior anti-PD- 1 therapy, patients who have a BRAF wild-type tumor, patients who have a BRAF mutant tumor, patients with an LDH <ULN, or patients who have failed other prior therapies, such as BRAF directed therapy (also referred to herein as BRAF targeted therapy).

The patient may have undergone surgery or have unresectable tumors. Hence, the invention may be useful for treating tumor recurrence following surgery or following incomplete surgical removal of disease, i.e. while residual tumor remains.

The treatment is particularly effective in patients with BRAF-mutated melanoma who are BRAF targeted therapy naive. In other words, the treatment is particularly effective in patients who have not received prior BRAF targeted therapy.

The BRAF mutant tumor may, for example, comprise a missense BRAF variant, such as BRAF V600 mutant (e.g. V600E, V600K, V600R, V600D, V600E2, V600M, V600G), K601 (e.g. K601E), BRAF D594 mutant (e.g. D594N), BRAF L597 mutant, or BRAF G596 mutant. The BRAF-mutated melanoma may comprise a BRAF V600 mutant. The patient may comprise mutations in the BRAF gene (NCBI reference sequence number: NM_004333.6), such as c.1799 T>A (p.V600E), c,1798_1799delGTinsAA (p.V600K), c.l798_1799delGTinsAG (p.V600R), c,1799_1800delTGinsAC (p.V600D), c.l799_1800delTCinsAA (p.V600E2), c,1798G>A (p.V600M), c,1799T>G (p.V600G), c,1801A>G (p.K601E), c,1780G>A (p.D594N).

The BRAF targeted therapy may comprise a BRAF inhibitor (BRAFi), as a monotherapy or a combination therapy. The BRAF targeted therapy may be a combined BRAF inhibitor (BRAFi) and MEK inhibitor (MEKi) therapy. The BRAFi may be vemurafenib (PEX4032), dabrafenib, and encorafenib. The MEKi may be trametinib, cobimetinib, or binimetinib.

In one aspect, the treatment method results in an overall response rate (ORR) of greater than 30% analyzed by RECIST vl .1. The treatment method may result in an ORR of greater than about 30% analyzed by RECIST vl .1. The treatment method may result in an ORR of greater than or equal to 30% analyzed by RECIST vl.l. In some embodiments, the treatment method results in an ORR of at least 30%, at least 30.5%, at least 31%, at least 31.5%, at least 32%, at least 32.5%, at least 32.7%, at least 33%, at least 33.5%, at least 34%, at least 34.5%, or at least 35% or more analyzed by RECIST vl.l.

In another aspect, the treatment method results in a median duration of response measured from baseline to end of response for responding patients of greater than 35 months analyzed by RECIST vl.l.

In another aspect, the treatment method results in a duration of response measured from baseline to end of response for responding patients of greater than 6 months analyzed by RECIST vl.l.

The treatment method may result in an overall response rate (ORR) of greater than about 30% analyzed by RECIST vl.l at at least about 12 months, such as at least about 13, 14, 15, or 16 months, following last administration of the oncolytic HSV. The treatment method may result in an ORR of greater than or equal to 30% analyzed by RECIST vl.l at at least about 12 months, such as at least about 13, 14, 15, or 16 months, following last administration of the oncolytic HSV. In some embodiments, the treatment method results in an ORR of at least 30%, at least 30.5%, at least 31%, at least 31.5%, at least 32%, at least 32.5%, at least 32.7%, at least 33%, at least 33.5%, at least 34%, at least 34.5%, or at least 35% or more analyzed by RECIST vl.l at at least about 12 months, such as at least about 13, 14, 15, or 16 months, following last administration of the oncolytic HSV. For example, the method may result in an ORR of greater than about 30% at about 12 months following last administration of the oncolytic HSV.

In an embodiment where the patient has BRAF mutant melanoma and is BRAF targeted therapy naive, the treatment method may result in an ORR of 13% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, 43% or more, 45% or more, or 50% or more e.g. as analyzed by RECIST vl.l.

In an embodiment where the patient has BRAF mutant melanoma and is BRAF targeted therapy naive, the treatment method may result in a duration of response or 3.5 months or more, 5 months or more, 10 months or more, 15 months or more, 20 months or more, 25 months or more, 30 months or more, 33 months or more, 35 months or more, 40 months or more, 45 months or more, 50 months or more, or 60 months or more e.g. as analyzed by RECIST vl.l.

In an embodiment where the patient has BRAF mutant melanoma and is BRAF targeted therapy naive, the treatment method may result in an improved response compared to the response observed when a patient who has previously received BRAF targeted therapy is treated using a method described herein, e.g. a method which comprises administering a therapeutically effective amount of an oncolytic HSV as described herein and an anti-PD-1 antibody as described herein to the patient.

The improved response may comprise an improved ORR and/or an increased duration of response. The improved response may comprise an improved ORR. For example, the ORR may be improved by about 5% or more, about 10% or more, about 15% or more, about 20% or more, about 25% or more, about 30% or more, or about 35% or more. The improved response may comprise an increased duration of response. For example, the duration of response may be increased by about 3.5 months or more, about 5 months or more, about 10 months or more, about 15 months or more, about 20 months or more, about 25 months or more, about 30 months or more, about 33 months or more. The improved response may comprise: (a) an improved ORR, wherein the ORR may be improved by about 5% or more, about 10% or more, about 15% or more, about 20% or more, about 25% or more, about 30% or more, or about 35% or more; and (b) an increased duration of response, wherein the duration of response may be increased by about 3.5 months or more, about 5 months or more, about 10 months or more, about 15 months or more, about 20 months or more, about 25 months or more, about 30 months or more, or about 33 months or more.

In another aspect, the treatment method results in reduction in the size of at least one lesion by at least 30% compared to baseline.

In another aspect, the treatment method results in no adverse events above Grade 3 as determined by the Common Toxicity Criteria for Adverse Events (CTCAE) is provided. The treatment may result in reduction in the size of at least one, e.g. at least 2, 3, 4, 6, 7, 8, 9, 10, of the injected lesions compared to baseline. The reduction may be at least 30%, e.g. at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90% or 100%, compared to baseline.

The treatment may result in reduction in the size of at least one, e.g. at least 2, 3, 4, 6, 7, 8, 9, 10, of the non-injected lesions compared to baseline. The reduction may be at least 30%, e.g. at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90% or 100%, compared to baseline.

The treatment may result in a partial response.

The treatment may result in a complete response.

The treatment may result in the reduction of tumor progression.

Tumor size and disease progression may be measured by any techniques known in the art, e.g. by clinical assessment or by imaging, e.g. MRI scans, over time.

The treatment may produce a reduction in major adverse vascular events (MAVEs) (e.g. fatigue, chills, pyrexia, nausea, influenza like illness, pruritus, diarrhoea, injection site pain, vomiting, headache, rash, myalagia, decreased appetite, or injection site reaction, rash maculo -popular, eczema, hyponatremia, hypophysitis, immune-mediated hepatitis, lipase increased, cytokine release syndrome, myocarditis and hepatic cytolysis, or immune mediated mycarditits), as described in further detail in the Examples. The treatment may result in MAVEs below Grade 3, e.g. Grade 1 or Grade 2, as determined by the Common Toxicity Criteria for Adverse Events (CTCAE).

The treatment may result in reduction in dose limiting toxicities.

The oncolytic HSV described herein may be administered to a subject by any suitable route. Typically, the oncolytic HSV is administered by direct intra-tumoral injection, including through the use of imaging guidance to target the tumor or tumors. Intra-tumoral injection includes direct injection into superficial skin, subcutaneous or nodal tumors, and imaging guided (including CT, MRI or ultrasound) injection into deeper or harder to localize deposits including in visceral organs and elsewhere. The oncolytic HSV may be administered into a body cavity, for example into the pleural cavity, bladder or by intra-peritoneal administration. The virus may be injected into a blood vessel, preferably a blood vessel supplying a tumor.

For example, the oncolytic HSV may be administered by injection into at least one lesion, such as 2, 3, 4, 5, 6, 7, 8, 9 10 or more lesions, in the patient. The oncolytic HSV may be injected into a superficial lesion. The oncolytic HSV may be injected into a visceral lesion. Subsequent doses of the oncolytic HSV may be administered to the same and/or different lesions to previous doses.

Treatment is effective when the oncolytic HSV and the anti-PD- 1 antibody are administered according to a treatment schedule. The treatment schedule may comprise an initial dose of the oncolytic HSV at day 1 of the administration schedule, a second dose of the oncolytic HSV at week 2 to 6 of the administration schedule, and subsequent multiple doses of the oncolytic HSV at every 2 to 6 weeks thereafter; and an initial dose of the anti- PD- 1 antibody at week 2 to 6 of the administration schedule, and subsequent multiple doses of the anti-PD- 1 antibody at every 2 to 6 weeks thereafter.

The oncolytic HSV may be administered 2 weeks, 3 weeks, 4 weeks, 5 weeks or 6 weeks apart. The oncolytic HSV may be administered 2 weeks apart.

The anti-PD- 1 antibody may be administered 2 weeks, 3 weeks, 4 weeks, 5 weeks or 6 weeks apart. The anti-PD- 1 antibody may be administered 2 weeks apart. The anti- PD- 1 antibody may be administered 4 weeks apart. The anti-PD- 1 antibody may be administered 2 weeks apart for eight doses followed by 4 weeks a part for the subsequent multiple doses.

The dosing with the anti-PD- 1 antibody may begin at the second dose of the oncolytic HSV in the administration schedule. Hence, the initial dose of the anti-PD- 1 antibody may be administered on the same day as the second dose of the oncolytic HSV. The subsequent multiple doses of the anti-PD- 1 antibody may be administered on the same day as the subsequent multiple doses of the oncolytic HSV.

The administration schedule may comprise a period of up to eight doses of the oncolytic HSV at every 2 to 6 weeks, whilst administration of multiple doses of the anti- PD- 1 antibody (starting at the second dose of the oncolytic HSV) continues at every 2 to 6 weeks even after the end of the period of the oncolytic HSV. The administration schedule may further comprise a second period of eight doses of the oncolytic HSV after pausing administration of the oncolytic HSV for e.g. up to 1, 2, or 3 months.

The administration schedule may comprise a total of 29 doses of the anti-PD- 1 antibody, and one more period of up to eight doses of the oncolytic HSV at every 2 to 6 weeks.

The administration schedule may be for up to 3 months, 6 months, 9 months, 12 months, 15 months, 18 months, 21 months, two years, three years, or chronically, e.g. for the remainder of the patient’s life. Multiple doses of an oncolytic HSV and an anti-PD-1 antibody as described herein provide an immunological or clinical effect. Repeat doses of either or both of the oncolytic HSV and the anti-PD-1 antibody may be given, depending on the speed of response of the tumor type being treated and the response of a particular patient, and any combination therapy which may also be being given.

Additional courses of up to 8 injections of the oncolytic HSV (e.g. RP1) may be given if, for example, the following criteria are met in both study: the patient has injectable disease and lesions that are safe to inject; the patient has stable performance status and in the opinion of the Investigator is deriving clinical benefit; and the patient did not experience either of the following during the first course of oncolytic HSV (e.g. RP1) treatment: a Grade 4 AE, a Grade 3 injection site reaction (e.g., injection site necrosis) lasting > 14 days, a suspected immune-mediated adverse event (imAE) Grade 3 event or Grade 3 infections lasting more > 14 days, unless the AE was deemed not related to RP1.

Per course, patients who re-initiate dosing of the oncolytic HSV (e.g. RP1) may be dosed with up to 8 intr-tuumoral (IT) injections at 1 x 10⁷ PFU/mL Q2W, either in combination with IV administration of the anti-PD-1 antibody (e.g. nivolumab) at 480 mg Q4W (or at 240 mg Q2W), or as monotherapy if the anti-PD-1 antibody (e.g. nivolumab) was previously stopped due to toxicity related to the anti-PD-1 antibody (e.g. nivolumab). The anti-PD-1 antibody (e.g. nivolumab) may be re-initiated in combination with the oncolytic HSV (e.g. RP1) if treatment was stopped for reasons other than toxicity.

The additional courses of the oncolytic HSV (e.g. RP1) may be given for persistent or progressive lesions if persistence or progression is confirmed after at least 4 weeks, or for new lesion(s), at any time within 24 months from treatment initiation with the oncolytic HSV (e.g. RP1).

The re-initiation of the oncolytic HSV (e.g. RP1) dosing may occur into any injectable lesions that are present, including new lesions, irrespective of which lesions were previously injected or which route of injection (superficial or deep) was previously used.

The oncolytic HSV and anti-PD- 1 antibody as described herein may be administered in combination with further therapeutic agents, including chemotherapy, targeted therapy, immunotherapy (including immune co-inhibitory pathway blockade (immune checkpoint blockade) or immune co-stimulatory pathway activation, such as using one or more antagonist of an immune co-inhibitory pathway and/or one or more agonist of an immune co-stimulatory pathway) and/or in combination with radiotherapy and/or in combination with any combination of these. The therapeutic agent is preferably an anti-cancer agent.

The further therapeutic agent may be a tyrosine kinase inhibitor, such as a MEK inhibitor, such as for example trametinib, a BRAF inhibitor, such as for example verurafenib and/or dabrafenib and/or a PI3 kinase inhibitor.

The further therapeutic agent may be a second virus, such as a second oncolytic virus.

For example, the further therapeutic agent may comprise an immunogen (including a recombinant or naturally occurring antigen, including such an antigen or combination of antigens delivered as DNA or RNA in which it/they are encoded), to further stimulate an immune response, such as a cellular or humoral immune response, to tumor cells, particularly tumor neoantigens. The further therapeutic agent may be an agent intended to increase or potentiate an immune response, such as a cytokine, an agent intended to inhibit an immune checkpoint pathway or stimulate an immune potentiating pathway or an agent which inhibits the activity of regulatory T cells (Tregs) or myeloid derived suppressor cells (MDSCs).

The further therapeutic agent may be an agent known for use in an existing cancer therapeutic treatment. The further therapeutic agent may be radiotherapy or a chemotherapeutic agent. The further therapeutic agent may be selected from cyclophosmamide, alkylating-like agents such as cisplatin or melphalan, plant alkaloids and terpenoids such as vincristine or paclitaxel (Taxol), antimetabolites such as 5- fluorouracil, topoisomerase inhibitors type I or II such as camptothecin or doxorubicin, cytotoxic antibiotics such as actinomycin, anthracyclines such as epirubicin, glucocorticoids such as triamcinolone, inhibitors of protein, DNA and/or RNA synthesis such as methotrexate and dacarbaxine, histone deacetylase (HD AC) inhibitors, or any other chemotherapy agent.

The further therapeutic agent may be one, or a combination of: immunotherapeutics or immunomodulators, such as TER agonists; agents that down-regulate T-regulatory cells such as cyclophosphamide; or agents designed to block immune checkpoints or stimulate immune potentiating pathways, including but not limited to monoclonal antibodies, such as a CTEA-4 inhibitor, a PD-E1 inhibitor, a EAG-3 inhibitor, a TIM-3 inhibitor, a VISTA inhibitor, a CSF1R inhibitor, an IDO inhibitor, a CEACAM1 inhibitor, a GITR agonist, a 4-1-BB agonist, a KIR inhibitor, a SEAMF7 inhibitor, an 0X40 agonist, a CD40 agonist, an ICOS agonist or a CD47 inhibitor. In a preferred embodiment, the therapeutic agent is a CTLA-4 inhibitor such as an anti-CTLA-4 antibody, or a PD-L1 inhibitor such as an anti- PD-L1 antibody. Such inhibitors, agonists and antibodies can be generated and tested by standard methods known in the art.

Immunotherapeutic agents may also include bi-specific antibodies, cell based- therapies based on dendritic cells, NK cells or engineered T cells such CAR-T cells or T cells expressing engineered T cell receptors. Immunotherapeutic agents also include agents that target a specific genetic mutation which occurs in tumors, agents intended to induce immune responses to specific tumor antigens or combinations of tumor antigens, including neoantigens and/or agents intended to activate the STING/cGAS pathway, TLR or other innate immune response and/or inflammatory pathway, including intra-tumoral agents.

Where a further therapeutic agent and/or radiotherapy is used in conjunction with the oncolytic HSV and the anti-PD-1 antibody as described herein, administration of the virus and the further therapeutic agent and/or radiotherapy may be contemporaneous or separated by time. The oncolytic HSV and the anti-PD-1 antibody of the disclosure may be administered before, together with or after the further therapeutic agent or radiotherapy. The method of treating advanced solid tumor may comprise multiple administrations of the oncolytic HSV and the anti-PD-1 antibody and/or of the therapeutic agent and/or radiotherapy. A skilled practitioner will readily be able to determine suitable courses of administration of the virus and the therapeutic agent.

Also provided is an oncolytic herpes simplex virus (HSV) for use in a method of treating advanced solid tumor in a patient who failed anti-PD-1 therapy as described herein, comprising administering a therapeutically effective amount of the oncolytic herpes simplex virus (HSV) and an anti-PD-1 antibody, wherein the oncolytic HSV comprises genes encoding (i) a glycoprotein from gibbon ape leukemia virus (GALV) from which the R peptide has been deleted (GALV-R-) and (ii) GM-GSF.

Also provided is an anti-PD- 1 antibody for use in a method of treating advanced solid tumor in a patient who failed anti-PD- 1 therapy as described herein, comprising administering a therapeutically effective amount of and oncolytic herpes simplex virus (HSV) and the anti-PD- 1 antibody, wherein the oncolytic HSV comprises genes encoding (i) a glycoprotein from gibbon ape leukemia virus (GALV) from which the R peptide has been deleted (GALV-R-) and (ii) GM-GSF. Also provided is an oncolytic herpes simplex virus (HSV) for the preparation of a medicament for use in a method of treating advanced solid tumor in a patient who failed anti-PD-1 therapy in combination with an anti-PD-1 antibody as described herein.

Also provided is an anti-PD- 1 antibody for the preparation of a medicament for use in a method of treating advanced solid tumor in a patient who failed anti-PD-1 therapy in combination with an oncolytic herpes simplex virus (HSV) as described herein.

Oncolytic HSV

The oncolytic HSV used in the treatments described herein effectively kills tumor cells and spread within tumors results in optimal direct anti-tumor effects. Efficient spread and virus replication associated lysis of tumor cells also maximises the amount of tumor antigen released and therefore also maximises the potency of the anti-tumor immune response induced. The oncolytic HSV described herein is capable of replicating selectively in human tumors. The oncolytic HSV may comprise one or more mutations in one or more viral genes that inhibit replication in normal tissue but still allow replication in tumors.

The oncolytic HSV may be a strain of HSV 1. The strain of HSV 1 may be strain RH018A having the accession number ECACC 16121904.

The oncolytic HSV encodes (i) a glycoprotein from gibbon ape leukemia virus (GALV) from which the R peptide has been deleted (GALV-R-) (e.g. as set out in SEQ ID NO: 6) and (ii) human GM-GSF (e.g. as set out in SEQ ID NO: 3). In other words, the oncolytic HSV comprises: (i) a gene encoding GALVR- (e.g. as set out in SEQ ID NO: 4), and (ii) a gene encoding human GM-CSF (e.g. as set out in SEQ ID NO: 1). The genes encoding GALVR- and human GM-CSF are each under the control of a promoter sequence. As replication of such a virus will occur selectively in tumor tissue, expression of the proteins encoded by the heterologous genes in the virus is also enhanced in tumor tissue as compared to non-tumor tissue in the body. Enhanced expression occurs where expression is greater in tumors as compared to other tissues of the body. Proteins expressed by the oncolytic virus would also be expected to be present in oncolytic virus- infected tumor draining lymph nodes, including due to trafficking of expressed protein and of virus in and on antigen presenting cells from the tumor. Accordingly, expression of GALV-R- and GM-GSF beneficially occurs selectively in tumors combined with the antitumor effect provided by oncolytic virus replication. The oncolytic HSV may contain a further mutation or mutations which enhance replication of the HSV in tumors. The resulting enhancement of viral replication in tumors not only results in improved direct ‘oncolytic’ tumor cell killing by the virus, but also enhances the level of heterologous gene expression and increases the amount of tumor antigen released as tumor cells die, both of which may also improve the immunogenic properties of the therapy for the treatment of cancer. The ICP47-encoding gene may be deleted in a manner that places the US11 gene under the control of the immediate early promoter that normally controls expression of the ICP47 encoding gene leads to enhanced replication in tumors.

The oncolytic HSV may not express functional ICP34.5, may not express function ICP47, and/or may express the US11 gene as an immediate early gene. The ICP47- encoding gene may be deleted such that the US11 gene is under the control of the ICP47 immediate early promoter.

The genes referred to above, the functional inactivation of which may provide the property of tumor selectivity to the virus, may be rendered functionally inactive by any suitable method, for example by deletion or substitution of all or part of the gene and/or control sequence of the gene or by insertion of one or more nucleic acids into or in place of the gene and/or the control sequence of the gene. For example, homologous recombination methods, which are standard in the art, may be used to generate the virus of the disclosure.

As used herein, the term “gene” is intended to mean the nucleotide sequence encoding a protein, i.e. the coding sequence of the gene. The various genes referred to above may be rendered non-functional by mutating the gene itself or the control sequences flanking the gene, for example the promoter sequence. Deletions may remove one or more portions of the gene, the entire gene or the entire gene and all or some of the control sequences. For example, deletion of only one nucleotide within the gene may be made, resulting in a frame shift. However, a larger deletion may be made, for example at least about 25%, more preferably at least about 50% of the total coding and/or non-coding sequence. In one preferred embodiment, the gene being rendered functionally inactive is deleted. For example, the entire gene and optionally some of the flanking sequences may be removed from the virus. Where two or more copies of the gene are present in the viral genome both copies of the gene are rendered functionally inactive.

A gene may be inactivated by substituting other sequences, for example by substituting all or part of the endogenous gene with a heterologous gene and optionally a promoter sequence. Where no promoter sequence is substituted, the heterologous gene may be inserted such that it is controlled by the promoter of the gene being rendered nonfunctional. In the oncolytic HSV, it is preferred that the ICP34.5 encoding-genes are rendered non-functional by the insertion of a heterologous gene or genes and a promoter sequence or sequences operably linked thereto, and optionally other regulatory elements such as polyadenylation sequences, into each the ICP34.5-encoding gene loci.

The oncolytic HSV described herein may comprise multiple copies of each of the heterologous genes, e.g. two copies of the gene encoding GALV-R- and two copies of the gene encoding GM-CSF.

In the oncolytic HSV, an expression cassette is typically inserted into each of the two ICP34.5 gene loci. The expression cassette may include a gene encoding human GM- CSF under the control of a first promoter (Pl) in back to back orientation with a gene encoding GALV-R- under the control of a second promoter (P2). Each of the genes in the expression cassette is terminated with a polyA sequence (pAl and pA2). Pl may, for example, be a CMV promoter. P2 may, for example, be a RSV promoter.

The HSV 1 may in one aspect comprise one or more further heterologous genes in addition to GALV-R- and GM-GSF, such as further fusogenic and/or immune stimulatory proteins.

The sequences of the heterologous genes, for example, the genes encoding GALV-R- and GM-GSE, may be codon optimized so as to increase expression levels of the respective proteins in target cells as compared to if the unaltered sequence is used.

The term “antibody” as referred to herein includes whole antibodies and any antigen binding fragment (i.e., “antigen-binding portion”) or single chains thereof. The antibody is typically a monoclonal antibody. The antibody may be a chimeric antibody. The antibody is preferably a humanised antibody and is more preferably a human antibody. Examples of antibody fragments include a Fab fragment, a F(ab')2 fragment, a Fab’ fragment, a Fd fragment, a Fv fragment, a dAb fragment and an isolated complementarity determining region (CDR). Single chain antibodies such as scFv and heavy chain antibodies such as VHH and camel antibodies are also intended to be encompassed within the term "antigen-binding portion" of an antibody.

The heterologous genes comprised in the oncolytic HSV described herein may have a naturally occurring nucleic acid sequence or a modified sequence. The sequence of the heterologous genes may, for example, be modified to provide codon optimisation and therefore increase the efficiency of expression of the encoded protein. Examples of codon optimised sequences are disclosed herein, e.g. the polynucleotide sequence of a codon optimised gene encoding GALV-R- is shown in SEQ ID NO: 5; and the polynucleotide sequence of a codon optimised gene encoding human GM-CSF is shown in SEQ ID NO: 2.

Oncolytic HSVs described herein may be constructed using methods well known in the art. For example, plasmids (for smaller viruses and single and multiple genome component RNA viruses) or BACS (for larger DNA viruses including herpes viruses) encoding the viral genome to be packaged, including any genes encoding desired heterologous genes, such as genes encoding (i) GALV-R- and (ii) GM-GSF, under appropriate regulatory control, can be constructed by standard molecular biology techniques and transfected into permissive cells from which recombinant viruses can be recovered.

Alternatively, plasmids containing DNA regions flanking the intended site of insertion can be constructed, and then co-transfected into permissive cells with viral genomic DNA such that homologous recombination between the target insertion site flanking regions in the plasmid and the same regions in the parental virus, such as the parental clinical isolate, occur. Recombinant viruses can then be selected and purified through the loss or addition of a function inserted or deleted by the plasmid used for modification, e.g. insertion or deletion of a marker gene such as GFP or lacZ from the parental virus at the intended insertion site. An insertion site in the oncolytic HSV may be the ICP34.5 locus, and therefore the plasmid used for manipulation contains HSV sequences flanking this insertion site, between which may be an expression cassette encoding GALV-R- and GM-GSF. In this case, the parental virus, such as HSV1 strain RH018A having the accession number ECACC 16121904, may contain a cassette encoding GFP in place of ICP34.5 and recombinant virus plaques are selected through the loss of expression of GFP. The US11 gene of HSV may also expressed as an IE gene. This may be accomplished through deletion of the ICP47 -encoding region, or by other means.

Heterologous genes, such as GALV-R- encoding sequences and GM-CSF encoding sequences encoding sequences may be inserted into the viral genome under appropriate regulatory control. This may be under the regulatory control of natural promoters of the HSV or preferably under the control of heterologous promoters. Each heterologous gene is typically under separate promoter control. RNA derived from each promoter is typically terminated using a polyadenylation sequence. Suitable heterologous promoters include mammalian promoters, such as the IEF2a promoter or the actin promoter. Viral promoters such as the CMV IE promoter, the RSV LTR, the MMLV LTR, other retroviral LTR promoters, or promoters derived from SV40 may be used. The heterologous genes may be driven by a different promoter selected from the CMV (e.g. human or mouse CMV promoter), the RSV promoter, the EFla promoter, the SV40 promoter and a retroviral LTR promoter. The retroviral LTR promoter may be from MMLV, which is also known as MoMuLV. The gene encoding GALV-R- may be under the control of the RSV promoter. The gene encoding GM-CSF gene may be under the control of the CMV promoter (e.g. human or mouse CMV promoter). Example sequences of promoters described herein are provided in the sequence listing herein.

Suitable polyadenylation sequences include mammalian sequences such as the bovine or human growth hormone (BGH) poly A sequence, synthetic polyadenylation sequences, the rabbit betaglobin (RBG) polyadenylation sequence, or viral sequences such as the SV40 early or late polyadenylation sequence. The poly adenylation sequences may be the same or different of the heterologous genes in the oncolytic HSV, e.g. selected from the BGH, SV40, HGH and RBG poly adenylation sequences. The GALV-R- gene may be terminated by the SV40 polyadenylation sequence. The GM-CSF gene may be terminated by the BGH polyadenylation sequence. Example sequences of polyadenylation sequences described herein are provided in the sequence listing herein.

Any combination of the various promoters and polyadenylation sequences may be used with any of the heterologous genes. For example, the oncolytic HSV may comprise (i) a GALV-R- gene under the control of the RSV promoter and terminated by the SV40 polyadenylation sequence, and (ii) a GM-CSF-encoding gene under the control of the CMV promoter (e.g. human or mouse CMV promoter) and terminated by the BGH polyadenylation sequence.

Anti-PD-1 antibody

Examples of suitable anti-PD-1 antibodies include nivolumab, pembrolizumab, cemiplimab, atezolizumab, durvalumab, avelumab, tislelizumab, retifanlimab, dostarlimab, JTX-4014, spartalizumab, camrelizumab, sintilimab, toripalimab, retifanlimab (INCMGA00012), AMP-224, MEDI0680 (AMP-514), sasanlimab, budigalimab, ezabenlimab (BI 754091), and zimberelimab (AB 122).

The anti-PD-1 antibody may be nivolumab, pembrolizumab, cemiplimab, atezolizumab, durvalumab, avelumab, tislelizumab, or retifanlimab. The anti-PD- 1 antibody may be nivolumab (also known as Opdivo) comprising heavy and light chains having the sequences shown in SEQ ID NOs: 16 and 17, respectively. Nivolumab is described in WO 2018/204405, the teachings or which are hereby incorporated by reference. The anti-PD- 1 antibody may, for example, comprise heavy and light chain sequences as set out in SEQ ID NOs: 16 and 17, respectively. The anti-PD- 1 antibody may comprise the heavy and light chain CDRs or variable regions of nivolumab. For example, the anti-PD- 1 antibody may comprise the CDR1, CDR2, and CDR3 domains of the VH region of nivolumab having the sequence set forth in SEQ ID NO: 18, and the CDR1, CDR2 and CDR3 domains of the VL region of nivolumab having the sequence set forth in SEQ ID NO: 19.

The CDR boundaries may be defined by numbering schemes known in the art, such as the Kabat numbering scheme, the Chothia numbering scheme, or the combined Kabat- Chothia numbering scheme.

The anti-PD- 1 antibody may comprise heavy chain CDR1, CDR2 and CDR3 domains having the sequences set forth in SEQ ID NOs:23, 24, and 25, respectively, and light chain CDR1, CDR2 and CDR3 domains having the sequences set forth in SEQ ID NOs:20, 21, and 22, respectively. The CDRs are defined by Kabat numbering. The anti- PD- 1 antibody may comprise VH and VL regions having the amino acid sequences set forth in SEQ ID NO: 18 and SEQ ID NO: 19, respectively.

The anti-PD- 1 antibody may be pembrolizumab comprising heavy and light chains having the sequences shown in SEQ ID NOs: 26 and 27, respectively. The anti-PD-1 antibody may, for example, comprise heavy and light chain sequences as set out in SEQ ID NOs: 26 and 27, respectively. The anti-PD-1 antibody may, for example, comprise the three CDRs comprised in SEQ ID NO: 26 and the three CDRs comprised in SEQ ID NO: 27.

The anti-PD- 1 antibody may be cemiplimab comprising heavy and light chains having the sequences shown in SEQ ID NOs: 28 and 29, respectively. The anti-PD-1 antibody may, for example, comprise heavy and light chain sequences as set out in SEQ ID NOs: 28 and 29, respectively. The anti-PD-1 antibody may, for example, comprise the three CDRs comprised in SEQ ID NO: 28 and the three CDRs comprised in SEQ ID NO: 29.

The anti-PD- 1 antibody may be durvalumab comprising heavy and light chains having the sequences shown in SEQ ID NOs: 30 and 31, respectively. The anti-PD-1 antibody may, for example, comprise heavy and light chain sequences as set out in SEQ ID NOs: 30 and 31, respectively. The anti-PD-1 antibody may, for example, comprise the three CDRs comprised in SEQ ID NO: 30 and the three CDRs comprised in SEQ ID NO: 31.

The anti-PD- 1 antibody may be atezolizumab comprising heavy and light chains having the sequences shown in SEQ ID NOs: 32 and 33, respectively. The anti-PD-1 antibody may, for example, comprise heavy and light chain sequences as set out in SEQ ID NOs: 32 and 33, respectively. The anti-PD-1 antibody may, for example, comprise the three CDRs comprised in SEQ ID NO: 32 and the three CDRs comprised in SEQ ID NO: 33.

The anti-PD-1 antibody may be avelumab comprising heavy and light chains having the sequences shown in SEQ ID NOs: 34 and 35, respectively. The anti-PD-1 antibody may, for example, comprise heavy and light chain sequences as set out in SEQ ID NOs: 34 and 35, respectively. The anti-PD-1 antibody may, for example, comprise the three CDRs comprised in SEQ ID NO: 34 and the three CDRs comprised in SEQ ID NO: 35.

The anti-PD-1 antibody may be dostarlimab comprising heavy and light chains having the sequences shown in SEQ ID NOs: 36 and 37, respectively. The anti-PD-1 antibody may, for example, comprise heavy and light chain sequences as set out in SEQ ID NOs: 36 and 37, respectively. The anti-PD-1 antibody may, for example, comprise the three CDRs comprised in SEQ ID NO: 36 and the three CDRs comprised in SEQ ID NO: 37.

Pharmaceutical Compositions

The oncolytic virus and the anti-PD-1 antibody as described herein, also referred to as agents herein, may be formulated in a pharmaceutical composition comprising a pharmaceutically acceptable carrier or diluent. Suitable carriers and diluents include isotonic saline solutions, for example phosphate-buffered saline. The composition may further comprise other constituents such as sugars or proteins to improve properties such as stability of the product. Alternatively, a lyophilized formulation may be used, which is reconstituted in a pharmaceutically acceptable carrier or diluent before use.

The choice of carrier, if required, is frequently a function of the route of delivery of the composition. Within this disclosure, compositions may be formulated for any suitable route and means of administration. Pharmaceutically acceptable carriers or diluents for the oncolytic HSV are those used in compositions suitable for intra-tumoral administration. Pharmaceutically acceptable carriers or diluents for the anti-PD-1 antibody are those used in compositions suitable for intravenous or intraarterial administration. The composition may be administered in any suitable form, preferably as a liquid.

As a guide, the amount of virus administered is in the case of HSV in the range of from 10⁴ to IO¹⁰ pfu, preferably from 10⁵ to 10⁹ pfu, such as 10⁴, 10⁵ or 10⁶ pfu. An initial lower dose (e.g. 10⁴ to 10⁷ pfu, such as 10⁶ pfu) may be given to patients to seroconvert patients who are seronegative for HSV and boost immunity in those who are seropositive, followed by a higher dose then being given thereafter (e.g. 10⁶ to 10⁹ pfu, such as 10⁷ pfu).

For example, in a treatment schedule described herein, the initial dose of the oncolytic HSV may be 10⁶ PFU/mL, and the second dose and each of the subsequent multiple doses of the oncolytic HSV may be 10⁷ PFU/mL.

Typically, up to 20ml, such as 15ml, 10ml or 5ml of a pharmaceutical composition consisting essentially of the virus and a pharmaceutically acceptable suitable carrier or diluent may be used for direct injection into tumors, or up to 50ml for administration into a body cavity (which may be subject to further dilution into an appropriate diluent before administration) or into the bloodstream. However, for some oncolytic therapy applications larger or smaller volumes may also be used, depending on the tumor and the administration route and site.

The anti-PD- 1 antibody useful for the treatment of the invention may be administered by intravenous administration.

The anti-PD-1 antibody, such as nivolumab, may be administered at a dose of about 100 mg, about 200mg, about 300 mg, about 500 mg, about 600 mg, or about 600 mg, such as 240 mg or 480 mg. For example, in a treatment schedule described herein, the first eight doses of the anti-PD-1 antibody may be 240 mg every two weeks, and each of the subsequent multiple doses of the anti-PD-1 antibody may be 480 mg every four weeks.

The dosage may be determined according to various parameters, especially according to the location of the tumor, the size of the tumor, the age, weight and condition of the patient to be treated and the route of administration.

The optimum route of administration will depend on the location and size of the tumor.

The oncolytic virus and anti-PD- 1 antibody may be administered by the regimen depicted in Figure 1. Kits

Also provided herein are kits which include agents described herein, such as an oncolytic HSV (e.g. RP1) and an anti-PD-1 antibody (e.g. nivolumab), and a pharmaceutically-acceptable carrier, wherein each agent is in a therapeutically effective amount adapted for use in the methods described herein. The kits optionally also can include instructions, e.g., comprising administration schedules, to allow a practitioner (e.g., a physician, nurse, or patient) to administer the composition contained therein to administer the oncolytic HSV and the anti-PD- 1 antibody to a patient who failed anti-PD- 1 therapy. The kit may also include a syringe or a needle for intratumoral administration of the oncolytic HSV.

In one embodiment, a kit for treating melanoma in a patient who failed anti-PD-1 therapy is provided, the kit comprising: (a) a dose of an oncolytic HSV comprises genes encoding (i) a glycoprotein from gibbon ape leukemia virus (GALV) from which the R peptide has been deleted (GALV-R-) and (ii) GM-GSF; (b) a dose of an anti-PD-1 antibody; and (b) instructions for using each agent in the methods described herein. The dose of each agent may be a dose as described herein.

The following examples illustrate the invention.

Phase 1/2 Multi-Cohort Clinical Trial of RP1 ± Nivolumab in Patients with anti-PD-1 failed cutaneous melanoma

A Phase 1/2, open label, dose escalation and expansion clinical study of RP1 alone and in combination with nivolumab in adult subjects with advanced and/or refractory solid tumors was conducted.

Overall design

A Phase 1/2, open label, multicenter, dose escalation and expansion, first-in-human (FIH) clinical study to evaluate the safety and tolerability, biodistribution, shedding, and preliminary efficacy of RP1 alone and in combination with nivolumab in adult subjects with advanced and/or refractory solid tumors was performed. An overview of the study is depicted in Figure 1. Phase 1 of the study demonstrated a tolerable safety profile for RP1 and RP1 combined with nivolumab (nivo) and determined the recommended phase 2 dose (RP2D). The objective of Phase 2 was to evaluate the safety and efficacy of RP1 combined with nivo in patients (pts) with a range of advanced solid tumors, including anti-PD- 1/PD-L1- failed mismatch repair deficiency, micro satellite instability, non-melanoma skin cancer, cutaneous melanoma, and non- small-cell lung cancer (NSCLC).

RP1 is a genetically modified herpes simplex type 1 virus (HSV1) that encodes a fusogenic glycoprotein (GALV-R-) and human granulocyte macrophage colony stimulating factor (GM-CSF). RP1 has been designed to directly destroy tumors and to generate an anti-tumor immune response.

Nivolumab is an anti-PD-1 monoclonal antibody. It is also known as Opdivo.

In phase 2, a cohort of anti-PD- 1 failed cutaneous melanoma patients received up to 10 mL of RP1 intratumorally into one or more superficial or deep seated/visceral lesions by imaging guidance at the RP2D identified in the Phase 1 portion of the study (1 x 10⁶ PFU/mL x 1 followed by 1 x 10⁷ PFU/mL x 7, Q2W). Following the first dose of RP1, Nivolumab (240 mg IV Q2W for 4 months, then 480 mg IV Q4W for up to 2 years) is subsequently administered in combination. Patients who met protocol- specified criteria received up to 8 additional doses of RP1. Tumor assessments were performed Q8W. The administration scheme is depicted in Figure 1.

Eligibility Criteria

The key eligibility criteria were: advanced melanoma having confirmed progression on prior anti-PD-1 therapy (non-neuro logical solid tumors); adequate organ function; no prior treatment with oncolytic therapy; and ECOG performance status 0-1. The criteria for prior anti-PD- 1-failure were: at least 8 weeks of prior anti-PD-1, confirmed progression while on anti-PD-1; anti-PD-1 must be the last therapy before clinical trial; patients on prior adjuvant therapy must have progressed while on prior adjuvant treatment (progression can be confirmed by biopsy).

Eligible patients were 18 years and older and must meet all inclusion and no exclusion criteria.

Inclusion Criteria:

1. Have an Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0-1.

2. At least one measurable and injectable lesion (>1 cm) 3. Have provided a former tumor pathology specimen or be willing to supply a new tumor sample from a biopsy

4. Have a predicted life expectancy of > 3 months

5. Measurable disease, according to Response Evaluation Criteria in Solid Tumors (RECIST) vl.l criteria (https://recist.eortc.org/recist-l-l-2/)

Subjects with anti-PD-1 failed cutaneous melanoma: has confirmed progressive disease while on anti-PD- 1 treatment for at least 8 weeks and documented BRAF mutation status

Exclusion Criteria:

1. Prior treatment with an oncolytic therapy

2. History of viral infections according to the protocol

3. Prior complications with herpes infections

4. Chronic use of anti-virals

5. Uncontrolled/untreated brain metastasis

6. History of interstitial lung disease

7. History of non-infectious pneumonitis

8. History of clinically significant cardiovascular disease

Outcome Measures

In the anti-PD-1 -failed cutaneous melanoma cohort (140 patients), the primary objectives were to assess the safety and tolerability and to assess efficacy as assessed by overall response rate (ORR) using modified Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 by independent central review. The secondary objective was to assess efficacy as determined by duration of response (DOR), complete response (CR) rate, disease control rate (DCR), progression-free survival (PFS), by central and investigator review, ORR by investigator review, and 1-year and 2-year overall survival (OS).

Baseline Clinical Characteristics

A ‘real world’ anti-PD-1 failed melanoma population was enrolled. Good representation of each of the sub-groups of patients who progress on prior anti-PD-1 therapy were included as shown in Table 1 below. Table 1: Baseline Clinical Characteristics anti-PD-1 therapy; ^bSecondary resistance: Progressed after 6 months of treatment on the immediate prior course of anti-PD-1 therapy; ^Cincludes 1 pt unknown resistance status. CR, complete response; CTLA-4, cytotoxic T-lymphocyte antigen 4; LDH, lactate dehydrogenase; PD, progressive disease; PD-1, programmed cell death protein 1; PD-L1, programmed death-ligand 1; PR, partial response; SD, stable disease; ULN, upper limit of normal; wt, wild-type. 1. Kluger HM, et al. J1TC. 2020:e000398

The median follow-up for all patients on study (n=156) was 15.4 months (range 0.5-55.5). Treatment-related adverse events (AEs)

RP1 combined with nivolumab continues to be a generally well tolerated regimen as shown in Tables 2 and 3 below. Predominantly grade 1/2 constitutional-type side effects were observed. There was a low incidence of grade 3 and 4 events, and no grade 5 events.

Table 2: Safety: Treatment-related AEs (N = 156)

Additional grade 3 and 4 events <5%

Grade 3: Two each of rash maculo-papular and hypophysitis; 1 each of tumor pain, infusion-related reaction, muscular weakness, abdominal pain, amylase increased, dermatitis bullous, eczema, immune-mediated enterocolitis, immune-mediated hepatitis, paresthesia, acute left ventricular failure, arthritis, cancer pain, enterocolitis, extranodal marginal zone B-cell lymphoma (MALT type), hyponatremia, injection site necrosis, left ventricular dysfunction, memory impairment, meningitis aseptic, edema, palmar-plantar erythrodysesthesia syndrome, peripheral sensory neuropathy, radiculitis brachial, sinus arrhythmia, tricuspid valve incompetence, and type 1 diabetes mellitus.

Grade 4: One each of lipase increased, alanine aminotransferase increased, blood bilirubin increased, cytokine release syndrome, myocarditis, and hepatic cytolysis, splenic rupture. Table 3: Safety: Treatment-related AEs (N = 140)

Additional grade 3 and 4 events <5%

Grade 3: Two each of rash maculo-papular and hypophysitis; 1 each of eczema, tumor pain, infusion-related reaction, muscular weakness, abdominal pain, amylase increased, dermatitis bullous, immune-mediated enterocolitis, paresthesia, acute left ventricular failure, cancer pain, enterocolitis, extranodal marginal zone B-cell lymphoma (MALT type), hyponatremia, left ventricular dysfunction, memory impairment, meningitis aseptic, palmar-plantar erythrodysesthesia syndrome, peripheral sensory neuropathy, radiculitis brachial, sinus arrhythmia, tricuspid valve incompetence, and type 1 diabetes mellitus

Grade 4: One each of lipase increased, cytokine release syndrome, myocarditis, splenic rupture, and hepatic cytolysis

Efficacy

The data presented in Table 4 below is investigator assessed data with all patients having at least 12 months follow up.

Approximately 1 in 3 patients achieved a response (32.7%). ORRs in different subgroups included:

27% ORR in patients who had prior anti-PD-1 & anti-CTLA-4; and 34% ORR in patients who are primary resistant to their prior anti-PD-1 therapy. Table 4: Investigator assessed efficacy data ^aEight patients were treated with sequential anti-CTLA-4 followed by anti-PD-1 (ORR for prior combined anti-CTLA-4/anti-PD- 1 was 25.8%) ^bIncludes one patient with unknown resistance status. The Primary Analysis of ORR by Investigator and Independent Central Review carried out in all patients with at least 12 months follow up (n=140), showed that around one third of patients respond when assessed by each of investigators, independent central review, modified RECIST 1.1 (per protocol) and RECIST 1.1, as shown in Table 5. Table 5: Primary Analysis of ORR

(range 0.5-47.6)

’ Each central reviewer selects their own target lesions without knowledge of RP1 injection status.

* Confirmation of progressive disease (PD) requires further tumor increase from the first observation of PD; responses can be captured at any time up until next anti-cancer therapy to allow for the potential for prolonged pseudo-progression (>1 scan interval) before response; however, in practice the pseudo-progression seen was transient (generally <1 scan interval)

** Responses not included in ORR after the first confirmed PD

Depth of Response

The depth of response is shown in Figure 4. Target tumors were reduced in >50% of patients. Responses were seen across disease stages, including CRs in patients with stage IVMlb/c disease.

Duration of Response

The duration of response is shown in Figure 5. A substantial proportion of patients achieve durable clinical benefit including those with stable disease (SD). 65% of responses were still ongoing at the time of the assessment. The responses were durable, with the duration of response being more than 6 months in 100% of patients, more than 12 months in 84.2% of patients, more than 18 months in 74.9% of patients and more than 24 months in 65.2% of patients.

Figure 6 shows the duration of response (time from baseline to end of response for responders) of the combined treatment with RP1 and nivolumab in melanoma patients who had failed anti-PD-1 therapy by investigator using mRECIST 1.1 (red line) vs. central review using RECIST 1.1 (blue line). The responses are highly durable, with median DOR >35 months, however assessed. The Kaplan-Meier median current duration is >35 months when assessed both by investigator and by RECIST 1.1 by independent central review. Conclusions

RP1 combined with nivolumab is a well-tolerated treatment regimen.

RP1 combined with nivolumab provides deep, durable & systemic responses in patients with confirmed progression on prior anti-PD-1 therapy.

Response rates are consistent across the different stages and prior treatment settings enrolled, including in patients with the most advanced disease, those who had previously received prior ipilimumab combined with nivolumab, and those with primary refractory disease.

The centrally reviewed primary analysis data shows clinically meaningful, durable benefit.

Around 1 in 3 patients responded by central review using both modified RECIST 1.1 (primary endpoint per protocol) and by RECIST 1.1.

100% of responses lasted >6 months, with median DOR >35 months.

The treatment has an attractive safety profile, with generally ‘on target’ and transient Grade 1-2 side effects, i.e. indicative of systemic immune activation

Overall the data indicates that RP1 has a profile which would be expected to be highly beneficial in the current treatment landscape.

Example 2

The data from Example 1 were further analysed for the baseline characteristics, duration of response and response by tumor type/prior lines of therapy, and the results are shown below.

Baseline clinical characteristics

The baseline clinical characteristics of the patients enrolled in the study are shown in Table 6 below.

Table 6: Baseline clinical characteristics

^aPrimary resistance: Progressed within 6 months of starting the immediate prior course of anti-PD-1 therapy. ^bSecondary resistance: Progressed after 6 months of treatment on the immediate prior course of anti-PD- 1 therapy. ^Clncludes one patient with unknown resistance status. CTLA-4, cytotoxic T-lymphocyte antigen 4; LDH, lactate dehydrogenase; PD, progressive disease; PD-1, programmed cell death protein 1; PD-L1, programmed death-ligand 1; ULN, upper limit of normal.

Primary Efficacy

The further analysed data on primary efficacy are shown in Table 7 below. The analysis was carried out by blinded, independent central review.

Table 7; Primary efficacy

The results show that 1 in 3 patients (33.6%) experienced a confirmed objective response, 15.0% CR.

Duration of response

The further analysed data on the duration of response of the combined treatment with RP1 and nivolumab in melanoma patients who had failed anti-PD-1 therapy using mRECIST 1.1 are shown in Figure 8.

Figure 8A shows the duration from response initiation of response and Figure 8B shows the duration of clinical benefit from baseline. The median Median (range) duration from response initiation was 21.6 months (1.2+ to 43.5+ months). Median (range) duration from baseline was 27.6 months (6.6+ to 45.3+ months). 85% of responses were ongoing >1 year from starting treatment. Efficacy

The further analysed data on efficacy are shown in Table 8 below. The responses (per protocol) of all patients have at least 12 months follow up were centrally reviewed using mRECIST v 1.1. Consistent response rates were seen across patient subgroups, including:

- 27.7% ORR in patients who had prior anti-PD-1 and anti-CTLA-4 therapies; and

- 35.9% ORR in patients who had primary resistance to anti-PD-1 therapy.

Table 8: Efficacy data includes one patient with unknown resistance status. Depth of Response

The further analysed data on the depth of response are shown in Figure 9 and Table 9. They show the change in size of individual injected and non-injected lesions over time analysed using mRECIST vl.l. All measurable lesions (10 max if >10 were present) were measured by central review for each patient with a best response of confirmed CR or PR. Central reviewers were blinded to lesion injection status.

Table 9: Depth of response

The results show that injected and non-injected lesions responded with similar frequency, depth, duration, and kinetics.

Figure 10 shows images taken at baseline and at 9 months from a patient who received prior adjuvant nivolumab followed by pembrolizumab as first line therapy before taking part in the IGNYTE study. The patient had stage IVMlc melanoma.

Overall survival

The probability of overall survival of patients over time is shown in Figure 11. One-, two-, and three-year survival rates were 75.3%, 63.3%, and 54.8%, respectively. Median overall survival has not been reached.

Treatment-related adverse events (AEs)

The further analysed data on treatment-related adverse events (AEs) are shown in Table 10 below. The results confirm that RP1 combined with nivolumab continues to be a generally well tolerated regimen. Predominantly grade 1 and 2 constitutional-type side effects were observed. There was a low incidence of grade 3 events (none occurring in >5% of patients), five grade 4 events in total, and no grade 5 events. Table 10: Safety: Treatment-related AEs (N = 141)

Additional grade 3/4 TRAEs (grade 4 italicized):

Two events each (1.4%): Hypophysitis, rash maculo-popular.

One event each (0.7%): Abdominal pain, acute left ventricular failure, amylase increased, cancer pain, cytokine release syndrome, eczema, enterocolitis, extranodal marginal zone B-cell lymphoma (MALT type), hepatic cytolysis, hyponatraemia, immune-mediated enterocolitis, infusion-related reaction, left ventricular dysfunction, lipase increased, memory impairment, meningitis aseptic, muscular weakness, myocarditis, palmar-plantar erythrodysaesthesia syndrome, paraesthesia, peripheral sensory neuropathy, radiculitis brachial, sinus arrhythmia, splenic rupture, tricuspid valve incompetence, tumor pain, type 1 diabetes mellitus.

Conclusions

RP1 combined with nivolumab following confirmed progression on prior anti-PD- 1 therapy alone or combined with anti-CTLA-4 demonstrated a clinically meaningful rate and duration of response, with ORR 33.6%; median DOR of 21.6 months.

Responses were seen in patients with advanced disease, including in non-injected visceral lesions.

Clinically meaningful activity was seen across all subgroups, including patients who had prior combined anti-PD-l/anti-CTLA-4 and with primary anti-PD-1 resistance.

The safety profile was favorable, with generally transient grade 1-2 side effects.

While the median OS has not been reached, 1- (75.3%), 2- (63.3%) and 3-year (54.8%) survival rates are promising, and further demonstrate long-term clinical benefit.

Example 3 - BRAF mutant patients

From the total of 140 patients in the IGNYTE study (Example 1 and 2), 53 patients had a BRAF mutant and 87 were wild type. Out of the 53 patients who had a BRAF mutant, 16 patients had received BRAF/MEK inhibitor therapy prior to taking part in the IGNYTE study, and 37 patients did not receive BRAF/MEK inhibitor therapy prior to taking part in the IGNYTE study.

The treatment responses of these BRAF mutant patients are shown in Figure 12 and Table 11. Treatment of the 16 BRAF mutant patients, who received BRAF/MEK inhibitor therapy prior to taking part in the IGNYTE study, with the combination of RP1 and nivolumab resulted in a 12.5% Overall Response Rate and 3-month median duration of response. Importantly, treatment of the 37 BRAF mutant patients, who did not receive BRAF/MEK inhibitor therapy prior to taking part in the IGNYTE study, with combined RP1 and nivolumab provided a 43.2% ORR and 33 month duration of response for BRAF mutant patients. Table 11: Patients with mutant BRAF status (53 out of 140 patients):

Some current standards of care indicate that BRAF mutant tumors should first receive a BRAF/MEK inhibitor therapy. However, the data provided here show that, with the combined treatment using RP1 and nivolumab, clinical benefit is achieved when the BRAF mutant melanoma patients are BRAF/MEK inhibitor therapy naive.

Therefore, the data show that the combined treatment of an oncolytic virus and an anti-PD- 1 antibody is surprisingly effective for BRAF mutant melanoma patients who are BRAF/MEK inhibitor therapy naive compared to BRAF mutant melanoma patients who had received BRAF/MEK inhibitor therapy. In another embodiment, the combined treatment of an oncolytic HS V and an anti-PD- 1 antibody is surprisingly effective for BRAF mutant melanoma patients who are BRAF/MEK inhibitor therapy naive compared to BRAF mutant melanoma patients who had received BRAF/MEK inhibitor therapy. In another embodiment, the combined treatment of RP1 and an anti-PD- 1 antibody is surprisingly effective for BRAF mutant melanoma patients who are BRAF/MEK inhibitor therapy naive compared to BRAF mutant melanoma patients who had received BRAF/MEK inhibitor therapy. In yet another embodiment, the combined treatment of RP1 and nivolumab is surprisingly effective for BRAF mutant melanoma patients who are BRAF/MEK inhibitor therapy naive compared to BRAF mutant melanoma patients who had received BRAF/MEK inhibitor therapy.

References

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Zimmer, L., S. Apuri, Z. Eroglu, L. A. Kottschade, A. Forschner, and R. Gutzmer, et al. 2017. 'Ipilimumab alone or in combination with nivolumab after progression on anti- PD-1 therapy in advanced melanoma', Eur J Cancer, 75: 47-55. Sequence Listing

Deposit Information

The HSV 1 strain RH018A was deposited at the ECACC, Culture Collections, Public Health England, Porton Down, Salisbury, SP4 OJG, United Kingdom on 19 December 2016 by Replimune Limited and were allocated the accession number 16121904.

Claims

1. A method of treating BRAF mutant melanoma in a patient, the method comprising administering a therapeutically effective amount of an oncolytic herpes simplex virus (HS V) and an anti-PD- 1 antibody to the patient, wherein the oncolytic HSV comprises genes encoding (i) a glycoprotein from gibbon ape leukemia virus (GALV) from which the R peptide has been deleted (GALVR-) and (ii) GM-GSF.

2. The method of claim 1, wherein the patient is BRAF targeted therapy naive.

3. The method of claim 2, wherein the BRAF targeted therapy is a combined BRAF and MEK inhibitor therapy.

4. The method of any one of claims 1 to 3, wherein the BRAF mutant melanoma comprises BRAF V600 mutant.

5. The method of any one of claims 1 to 4, wherein the oncolytic HSV is a modified HSV1 strain RH018A having the accession number ECACC 16121904.

6. The method of any one of claims 1 to 5, wherein the oncolytic HSV:

(a) does not express functional ICP34.5;

(b) does not express functional ICP47; and/or

(c) expresses the US11 gene as an immediate early gene.

7. The method of any one of claims 1 to 6, wherein the genes encoding (i) GALV-R- and (ii) GM-GSF are inserted into the ICP34.5 encoding loci of the oncolytic HSV.

8. The method of any one of claims 1 to 7, wherein the oncolytic HSV is RP1.

9. The method of any one of claims 1 to 8, wherein the anti-PD-1 antibody is nivolumab.

10. The method of any one of claims 1 to 9, wherein the method comprises administering to the patient: an initial dose of the oncolytic HSV at day 1 of an administration schedule, a second dose of the oncolytic HSV at week 2 to 6 of the administration schedule, and subsequent multiple doses of the oncolytic HSV at every 2 to 6 weeks thereafter; and an initial dose of the anti-PD-1 antibody at week 2 to 6 of the administration schedule, and subsequent multiple doses of the anti-PD-1 antibody at every 2 to 6 weeks thereafter.

11. The method of claim 10, wherein the initial dose of the oncolytic HSV is administered at 10⁶ PFU/mL, and the second dose and each of the subsequent multiple doses of the oncolytic HSV is administered at 10⁷ PFU/mL.

12. The method of claim 10 or 11, wherein the administration schedule comprises administering eight doses of the oncolytic HSV.

13. The method of any one of claims 1 to 12, wherein the administration schedule comprises administering the first eight doses of the anti-PD-1 antibody at 240 mg every two weeks, and each of the subsequent multiple doses of the anti-PD-1 antibody at 480 mg every four weeks.

14. The method of any one of claims 1 to 13, wherein the oncolytic HSV is administered by injection into a superficial lesion in the patient.

15. The method of any one claims 1 to 14, wherein the oncolytic HSV is administered by injection into a visceral lesion in the patient.

16. The method of any one of claims 1 to 15, wherein the anti-PD-1 antibody is administered by intravenous administration.

17. The method of any one claims 1 to 16, wherein the treatment results in reduction in the size of at least one lesion by at least 30% compared to baseline.

18. The method of any one of claims 1 to 17, wherein the treatment method results in an ORR of 13% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, 43% or more, 45% or more, or 50% or more.

19. The method of any one of claims 1 to 18, wherein the treatment method results in a duration of response of 3.5 months or more, 5 months or more, 10 months or more, 15 months or more, 20 months or more, 25 months or more, 30 months or more, 33 months or more, 35 months or more, 40 months or more, 45 months or more, 50 months or more, or 60 months or more.

20. The method of any one of claims 1 to 19, wherein the treatment results in no adverse events above Grade 3 as determined by the Common Toxicity Criteria for Adverse Events (CTCAE).

21. The method of any one of claims 1 to 20, wherein the tumor stage of the patient is IIIb/IVMla.

22. The method of any one of claims 1 to 4620 wherein the tumor stage of the patient is IVMlb/c/d.

23. The method of any one of claims 1 to 22, wherein the patient previously received immunotherapy.

24. The method of claim 23, wherein the immunotherapy is an anti-PD-1 therapy, such as nivolumab, pembrolizumab, cemiplimab, atezolizumab, durvalumab, avelumab, avelumab, tislelizumab, or retifanlimab.

25. The method of claim 24, wherein the anti-PD-1 therapy is nivolumab, and the patient previously received nivolumab as single agent.

26. The method of claim 23, wherein the immunotherapy is an anti-PD-1 therapy combined with an anti-CTLA-4 therapy.

27. The method of claim 26, wherein the anti-PD-1 therapy is nivolumab and the anti- CTLA-4 therapy is ipilimumab.

28. The method of any one of claims 1 to 27, wherein the patient has primary refractory disease.

29. The method of any one of claims 2 to 28, wherein the patient is BRAF targeted therapy naive and the treatment method results in an improved response compared to the response observed when a patient who has previously received BRAF targeted therapy is treated using the method of any one of claims 1 and 4 to 28.

30. The method of claim 29, wherein the improved response comprises an improved ORR and/or an increased duration of response.

31. The method of claim 30, wherein the improved response comprises an improvement in ORR.

32. The method of claim 30 or 31, wherein the ORR is improved by about 5% or more, about 10% or more, about 15% or more, about 20% or more, about 25% or more, about 30% or more, or about 35% or more.

33. The method of any one of claims 30 to 32, wherein the improved response comprises an increased duration of response.

34. The method of any one of claims 30 to 33, wherein the duration of response is increased by about 3.5 months or more, about 5 months or more, about 10 months or more, about 15 months or more, about 20 months or more, about 25 months or more, about 30 months or more, about 33 months or more.

35. The method of any one of claims 30 to 34, wherein the improved response is an improvement in ORR and an increased duration of response.

36. The method of any one of claims 30 to 35, wherein the ORR is improved by about 5% or more, about 10% or more, about 15% or more, about 20% or more, about 25% or more, about 30% or more, or about 35% or more; and wherein the duration of response is increased by about 3.5 months or more, about 5 months or more, about 10 months or more, about 15 months or more, about 20 months or more, about 25 months or more, about 30 months or more, or about 33 months or more.

37. An oncolytic herpes simplex virus (HSV) for use in a method of treating BRAF mutant melanoma in a patient, wherein the oncolytic HSV comprises genes encoding (i) a glycoprotein from gibbon ape leukemia virus (GALV) from which the R peptide has been deleted (GALVR-) and (ii) GM-GSF, wherein method further comprises administering an anti-PD- 1 antibody to the patient.

38. An anti-PD- 1 antibody for use in a method of treating BRAF mutant melanoma in a patient, wherein method further comprises administering an oncolytic herpes simplex virus (HSV) to the patient, wherein the oncolytic HSV comprises genes encoding (i) a glycoprotein from gibbon ape leukemia virus (GALV) from which the R peptide has been deleted (GALVR-) and (ii) GM-GSF.

39. An oncolytic herpes simplex virus (HSV) and an anti-PD- 1 antibody for use in a method of treating BRAF mutant melanoma in a patient, wherein the oncolytic HSV comprises genes encoding (i) a glycoprotein from gibbon ape leukemia virus (GALV) from which the R peptide has been deleted (GALVR-) and (ii) GM-GSF.

40. The oncolytic HSV and/or the anti-PD-1 antibody for use according to any one of claims 37 to 39, wherein the patient is BRAF targeted therapy naive.

41. The oncolytic HSV and/or the anti-PD-1 antibody for use according to any one of claims 37 to 40, wherein the method of treating melanoma is a method defined in any one of claims 3 to 36.

42. A method of treating melanoma in a patient who failed anti-PD-1 therapy, comprising administering a therapeutically effective amount of an oncolytic herpes simplex virus (HSV) and an anti-PD-1 antibody to the patient, wherein the oncolytic HSV comprises genes encoding (i) a glycoprotein from gibbon ape leukemia virus (GALV) from which the R peptide has been deleted (GALVR-) and (ii) GM-GSF, wherein the method results in an overall response rate (ORR) of greater than 30% analyzed by RECIST vl .1.

43. The method of claim 42, wherein the treatment method results in an ORR of at least 30.5%, at least 31%, at least 31.5%, at least 32%, at least 32.5%, at least 33%, at least 33.5%, at least 34%, at least 34.5%, or at least 35% or more analyzed by RECIST vl.l.

44. A method of treating melanoma in a patient who failed anti-PD-1 therapy, comprising administering a therapeutically effective amount of an oncolytic herpes simplex virus (HSV) and an anti-PD-1 antibody to the patient, wherein the oncolytic HSV comprises genes encoding (i) a glycoprotein from gibbon ape leukemia virus (GALV) from which the R peptide has been deleted (GALVR-) and (ii) GM-GSF, wherein the method results in a duration of response measured from baseline to end of response for responding patients of greater than 6 months analyzed by RECIST vl.l.

45. A method of treating melanoma in a patient who failed anti-PD-1 therapy, comprising administering a therapeutically effective amount of an oncolytic herpes simplex virus (HSV) and an anti-PD-1 antibody to the patient, wherein the oncolytic HSV comprises genes encoding (i) a glycoprotein from gibbon ape leukemia virus (GALV) from which the R peptide has been deleted (GALVR-) and (ii) GM-GSF, wherein the method results in a median duration of response measured from baseline to end of response for responding patients of greater than 35 months analyzed by RECIST v 1.1.

46. The method of any one of claims 42 to 45, wherein the method results in an ORR of greater than about 30% at at least about 12 months following last administration of the oncolytic HSV.

47. The method of any one of claims 42 to 46, wherein the oncolytic HSV is a modified HSV 1 strain RH018A having the accession number ECACC 16121904.

48. The method of any one of claims 42 to 47, wherein the oncolytic HSV:

(a) does not express functional ICP34.5;

(b) does not express functional ICP47; and/or

(c) expresses the US11 gene as an immediate early gene.

49. The method of any one of claims 42 to 48, wherein the genes encoding (i) GALV-R- and (ii) GM-GSF are inserted into the ICP34.5 encoding loci of the oncolytic HSV.

50. The method of any one of claims 42 to 49, wherein the oncolytic HSV is RP1.

51. The method of any one of claims 42 to 50, wherein the anti-PD-1 antibody is nivolumab, atezolizumab, durvalumab, pembrolizumab, avelumab, cemiplimab, avelumab, tislelizumab, or retifanlimab.

52. The method of any one of claims 42 to 51, wherein the method comprises administering to the patient: an initial dose of the oncolytic HSV at day 1 of an administration schedule, a second dose of the oncolytic HSV at week 2 to 6 of the administration schedule, and subsequent multiple doses of the oncolytic HSV at every 2 to 6 weeks thereafter; and an initial dose of the anti-PD-1 antibody at week 2 to 6 of the administration schedule, and subsequent multiple doses of the anti-PD-1 antibody at every 2 to 6 weeks thereafter.

53. The method of claim 52, wherein the initial dose of the oncolytic HSV is administered at 10⁶ PFU/mL, and the second dose and each of the subsequent multiple doses of the oncolytic HSV is administered at 10⁷ PFU/mL.

54. The method of claim 53, wherein the administration schedule comprises administering eight doses of the oncolytic HSV.

55. The method of any one of claims 42 to 54, wherein the administration schedule comprises administering the first eight doses of the anti-PD-1 antibody at 240 mg every two weeks, and each of the subsequent multiple doses of the anti-PD-1 antibody at 480 mg every four weeks.

56. The method of any one of claims 42 to 55, wherein the oncolytic HSV is administered by injection into a superficial lesion in the patient.

57. The method of any one of claims 42 to 56, wherein the oncolytic HSV is administered by injection into a visceral lesion in the patient.

58. The method of any one of claims 42 to 57, wherein the anti-PD-1 antibody is administered by intravenous administration.

59. The method of any one of claims 42 to 58, wherein the treatment results in reduction in the size of at least one lesion by at least 30% compared to baseline.

60. The method of any one of claims 42 to 59, wherein the treatment results in no adverse events above Grade 3 as determined by the Common Toxicity Criteria for Adverse Events (CTCAE).

61. The method of any one of claims 42 to 60, wherein the tumor stage of the patient is IIIb/IVMla.

62. The method of any one of claims 42 to 61, wherein the tumor stage of the patient is IVMlb/c/d.

63. The method of any one of claims 42 to 62, wherein the patient previously received nivolumab as single agent.

64. The method of any one of claims 42 to 63, wherein the patient previously received ipilimumab combined with nivolumab.

65. The method of any one of claims 42 to 64, wherein the patient has primary refractory disease.

66. The method of any one of claims 42 to 65, wherein the melanoma is BRAF mutant melanoma.

67. The method of any one claims 42 to 66, wherein the patient is BRAF targeted therapy naive.

68. An oncolytic herpes simplex virus (HSV) for use in a method of treating melanoma in a patient who failed anti-PD- 1 therapy, wherein the oncolytic HSV comprises genes encoding (i) a glycoprotein from gibbon ape leukemia virus (GALV) from which the R peptide has been deleted (GALVR-) and (ii) GM-GSF, wherein the method further comprises administering an anti-PD- 1 antibody to the patient, and wherein the method results in: (a) an overall response rate (ORR) of greater than 30% analyzed by RECIST vl.l;

(c) a median duration of response measured from baseline to end of response for responding patients of greater than 35 months analyzed by RECIST vl.l.

69. An anti-PD-1 antibody for use in a method of treating melanoma in a patient who failed anti-PD- 1 therapy, wherein the method further comprises administering an oncolytic herpes simplex virus (HSV) to the patient, wherein the oncolytic HSV comprises genes encoding (i) a glycoprotein from gibbon ape leukemia virus (GALV) from which the R peptide has been deleted (GALVR-) and (ii) GM-GSF, and wherein the method results in:

(a) an overall response rate (ORR) of greater than 30% analyzed by RECIST vl.l;

70. An oncolytic herpes simplex virus (HSV) and an anti-PD-1 antibody for use in a method of treating melanoma in a patient who failed anti-PD- 1 therapy, wherein the oncolytic HSV comprises genes encoding (i) a glycoprotein from gibbon ape leukemia virus (GALV) from which the R peptide has been deleted (GALVR-) and (ii) GM-GSF, and wherein the treatment method results in:

(a) an overall response rate (ORR) of greater than 30% analyzed by RECIST vl.l;

71. The oncolytic HS V and/or the anti-PD- 1 antibody for use according to any one of claims 68 to 70, wherein the method of treating melanoma is a method defined in any one of claims 42 to 67.