OBJECTIVES: The JAVELIN Merkel 200 trial assessed the efficacy and safety of first- (1L) or second-line (2L) avelumab in patients with metastatic MCC (a rare, aggressive skin cancer with considerable disease burden). A systematic literature review (SLR) and meta-analysis (MA) were conducted to synthesize avelumab’s real-world benefit in advanced MCC.

METHODS: Embase and MEDLINE were searched for relevant real-world studies published 2017–2023 reporting effectiveness and safety data for adults with advanced (stage III/IV) MCC who received 1L or 2L+ avelumab. A fixed-effect MA, stratified by disease stage (III/IV) and treatment line (1L/2L+), was conducted to assess 12-month overall and progression-free survival (OS/PFS) rates and response outcomes.

RESULTS: The SLR identified 16 studies (sample size: 4–558); eight were included in the MA because they reported data by disease stage and treatment line separately (1,237 patients). Mean age across eight studies was 74 (range: 67–78). Most patients were male (60.0%) and had ECOG performance status of 0–1 (81.7%). Pooled real-world effects were similar to JAVELIN. In 1L, 12-month OS and PFS rates (95% confidence interval) were higher for stage III vs IV: 77.7% (68.2, 85.1) vs 63.0% (53.8, 71.4) and 53.3% (39.0, 67.1) vs 39.3% (29.4, 50.2), respectively. In 2L+, stage IV OS and PFS rates were 53.7% (46.7, 60.6) and 37.4% (29.4, 46.2). Similar trends were observed for overall response (1L/stage III: 58.8% [35.2, 79.0]; 1L/stage IV: 54.6% [42.5, 66.1]; 2L+/stage IV: 50.7% [45.5, 55.9]) and complete response (1L/stage III: 29.4% [12.8, 54.2]; 1L/stage IV: 16.7% [9.5, 27.7]; 2L+/stage IV: 25.9% [21.6, 30.7]). Three additional studies reported adverse events (AEs); across treatment lines and disease stages, all-grade (28%–81%) and grade ≥3 AEs (9%–57%) were lower than in JAVELIN (60%–100%).

CONCLUSIONS: Real-world data confirm avelumab’s effectiveness and safety in advanced MCC beyond the stage IV MCC population in JAVELIN.