The study will enroll participants with unresectable or metastatic melanoma (Stage IIIC, IIID, or IV per the American Joint Committee on Cancer [AJCC] staging system) who have had no prior therapy for metastatic disease. Previous adjuvant/neoadjuvant therapy with a single line of protooncogene B-Raf (BRAF) inhibitor with or without a mitogen-activated protein kinase (MEK) inhibitor, PD-1 inhibitor, or cytotoxic T-lymphocyte-associated antigen-4 [CTLA-4] inhibitor is allowed, provided such treatment was completed ≥6 months before progression to metastatic disease.
This is a Phase 3, multicenter, open-label, randomized, parallel group, treatment study to assess the efficacy and safety of lifileucel in combination with pembrolizumab compared with pembrolizumab alone in participants with untreated, unresectable or metastatic melanoma. Participants randomized to the pembrolizumab monotherapy arm who subsequently have a blinded independent central review- verified confirmed progressive disease (PD) will be offered lifileucel monotherapy in an optional crossover period.