Overview

The purpose of this study is to evaluate the efficacy, safety, and tolerability of subcutaneous (SC) MK-3475A in Japanese participants with recurrent or metastatic cutaneous squamous cell carcinoma or locally advanced unresectable cSCC. The primary hypothesis is that MK-3475A will result in greater than 10% objective response rate (ORR) per Response Evaluation Criteria In Solid Tumors Version 1.1 (RECIST 1.1) as assessed by Blinded Independent Central Review (BICR).

Eligibility

The key inclusion and exclusion criteria include but are not limited to the following:

Inclusion Criteria:

• Has histologically confirmed cSCC by the investigator as the primary site of malignancy
• R/M cSCC cohort only: Has metastatic disease, defined as disseminated disease distant to the initial/primary site of diagnosis, and/or has locally recurrent disease that has been previously treated (with either surgery or radiotherapy) and is not curable by either surgery or radiotherapy
• LA unresectable cSCC cohort only: Is ineligible for surgical resection
• LA unresectable cSCC cohort only: Has received prior radiation therapy (RT) to index site or has been deemed to be not eligible for RT
• LA unresectable cSCC cohort only: Has received prior systemic therapy for curative intent are eligible regardless of regimen
• Has a life expectancy of greater than 3 months
• Must provide archival tumor tissue sample or newly obtained core or excisional biopsy of a tumor lesion not previously irradiated

Exclusion Criteria:

• Has cSCC that can be cured with surgical resection, radiotherapy, or with a combination of surgery and radiotherapy.
• Has any other histologic type of skin cancer other than invasive squamous cell carcinoma as the primary disease under study
• Has received prior systemic anticancer therapy including investigation agents within 4 weeks before allocation
• Has not adequately recovered from major surgery or has ongoing surgical complications
• Received prior radiotherapy within 2 weeks of study intervention, or had radiation-related toxicities, requiring corticosteroids
• Received a live or live-attenuated vaccine within 30 days before the first dose of study intervention
• Known additional malignancy that is progressing or has required active treatment within the past 2 years
• Has an ongoing active infection requiring systemic therapy
• Has a history of human immunodeficiency virus (HIV) infection
• Has an active autoimmune disease that has required systemic treatment in past 2 years
• Has history of allogenic tissue/organ transplant