Talimogene Laherparepvec with Pembrolizumab in Melanoma Following Progression on Prior Anti-PD-1 Based Therapy (MASTERKEY-115) (Mk-3475-A07/KEYNOTE-A07).

• Age ≥ 18 years with histologically confirmed diagnosis of stage IIIB to IVM1d melanoma and for whom surgery is not recommended. Subjects with stage IVM1d disease may be enrolled with up to 3 cerebral metastases, provided that all lesions have been adequately treated with stereotactic radiation therapy, craniotomy, or gamma knife therapy, with no evidence of progression and not requiring steroids for at least 2 months prior to enrollment. • Subjects must have measurable disease and be a candidate for intralesional therapy administration into cutaneous, subcutaneous, or nodal lesions. • Subjects must have had prior treatment (for at least 2 to 3 consecutive cycles within an 8 week period) with a PD-1 inhibitor and have confirmed disease progression (as defined by RECIST v1.1 criteria). The anti-PD-1 therapy must be the immediate prior line of therapy before enrollment and subjects with disease progression on more than 1 line of anti-PD-1 therapy are not eligible. • ECOG performance status of 0 or 1. • Adequate hematologic, renal, hepatic, and coagulation function.

• Subjects considered by the investigator to have rapid clinical progression due to melanoma • Subjects with prior treatment and disease progression on more than 1 line of anti-PD-1 therapy • Stage IVM1d subjects must not have greater than 3 cerebral melanoma metastases, or clinically active cerebral melanoma metastases requiring therapy, and/or carcinomatous meningitis regardless of clinical stability. • Primary uveal or mucosal melanoma, history or evidence of melanoma associated with immunodeficiency states or history of other malignancy within the past 3 years. • Subjects must not have history or evidence of symptomatic autoimmune glomerulonephritis, vasculitis, or other symptomatic autoimmune disease, or active autoimmune disease or syndrome requiring systemic treatment in the past 2 years (ie, with use of disease modifying agents, steroids or immunosuppressive agents) except vitiligo or resolved childhood asthma/atopy, or evidence of clinically significant immunosuppression. • Subjects may not have been previously treated with talimogene laherparepvec or any other oncolytic virus. • Subjects must not have active herpetic skin lesions or prior complications of herpetic infection and must not require intermittent or chronic treatment with an antiherpetic drug (eg, acyclovir), other than intermittent topical use.