Nghiem P, et al. - Researchers assessed response durability and overall survival (OS) in patients with advanced Merkel cell carcinoma (aMCC) receiving first-line anti–programmed cell death-1 therapy in this multicenter phase 2 trial (Cancer Immunotherapy Trials Network-09/Keynote-017). In 50 adults naïve to systemic therapy for aMCC, a treatment regimen of pembrolizumab (2 mg/kg every 3 weeks) for up to 2 years was implemented. With pembrolizumab, an objective response rate (ORR) of 56% was noted; in virus-positive and virus-negative tumors, the ORRs of 59% and 53%, respectively, were noted. The estimated 24-month OS rate was 68.7%. Compared with historical data from patients who received first-line chemotherapy, durable tumor control, a generally manageable safety profile, and favorable OS were displayed by pembrolizumab. This study represents the longest observation to date of aMCC patients treated with first-line anti–programmed cell death-1 therapy.