Avelumab for Advanced Merkel Cell Carcinoma: Global Real-World Data on Patient Response and Survival

INTRODUCTION: Avelumab is a programmed cell death-ligand 1 (PD-L1) inhibitor approved by the Food and Drug Administration for advanced Merkel cell carcinoma (MCC). Studies conducted in real-world settings have shed light on its effectiveness and safety in clinical settings. AREAS COVERED: Real-world studies on avelumab for MCC from North and South America, Europe, and Asia have been presented in this review. Most studies are on patients over age 70 and have a male-predominant sex ratio. Overall response rates range from 29.1% to 72.1%, (disease control rate: 60.0–72.7%; complete response rate: 15.8%–37.2%; partial rate: 18.2–42.1%; stable disease: 7.1–30.9%; progressive disease: 7.1–40.0%) and median progression free survival ranges from 8.1 to 24.1 months depending on the population studied. Immunosuppressed patients appear to benefit from avelumab as well, with response rates equivalent to the general population. Patients receiving avelumab as a first-line agent tend to have better outcomes than those using it as a second-line therapy. Fatigue, infusion-related reactions, and dyspnea were some of the most common adverse events identified in real-world studies. Autoimmune hepatitis and thyroiditis were also observed. CONCLUSION: The use of avelumab as a safe and effective treatment option for advanced MCC is supported by real-world data, although additional study is required to assess long-term efficacy and safety outcomes.