Background: Avelumab, an anti–PD-L1 antibody, has been approved in multiple countries for the treatment of mMCC based on the results of the pivotal phase 2 JAVELIN Merkel 200 trial (NCT02155647). In pts who received avelumab as 2L+ treatment in the trial (part A), median overall survival (OS) was 12.6 months and median progression-free survival (PFS) was 2.7 months. The French health technology assessment agency requested the collection of real-world data from pts with mMCC from a comprehensive registry; data are reported here. Methods: This retrospective, noninterventional, real-world study evaluated all pts with mMCC in France using combined data from 2 databases: CARADERM (French national database of rare dermatological cancers) and Système National des Données de Santé (SNDS; national healthcare database). For this analysis, eligible pts were diagnosed with mMCC and initiated 2L+ avelumab outside of a clinical trial between August 2016 and December 2019. Pts were followed for 24 months after initiation of avelumab. Probabilistic linkage was performed to identify pts registered in both databases. OS and PFS were analyzed using Kaplan-Meier methodology. Safety data were not collected. Results: A total of 180 pts who received 2L+ avelumab were identified, data were obtained for 112 pts from the CARADERM database and for 68 additional pts after SNDS linkage. Median age at diagnosis was 74.0 years, 66.7% were male, and 98.3% received chemotherapy as first-line treatment. Median follow-up was 13.1 months. 79.5% of CARADERM database pts had discontinued avelumab; the most common reasons specified were progressive disease (36.4%), complete response (17.0%), and death (13.6%). Median OS was 14.6 months (95% CI, 9.9-21.3 months) overall; in CARADERM database pts, median OS was 15.9 months (95% CI, 8.6-28.3 months) vs 13.3 months (95% CI, 6.7-19.1 months) in non-CARADERM database pts. 12- and 24-month OS rates in the overall population were 53.8% (95% CI, 46.2%-60.8%) and 40.5% (95% CI, 33.2%-47.6%), respectively. In CARADERM database pts (data not available in non-CARADERM database pts), median PFS was 3.6 months (95% CI, 2.7-7.5 months), and the objective response rate was 55.3% (95% CI, 45.3%-65.4%), including complete response in 31.9%. Median duration of response was 39.3 months (95% CI, 24.3 months-not estimable). Conclusions: In this real-world study of national data from France, outcomes with avelumab as 2L+ treatment for mMCC were similar to those observed in part A of the JAVELIN Merkel 200 trial. These findings confirm the effectiveness of avelumab in pts with mMCC that have progressed following first-line systemic treatment in routine clinical practice.