BACKGROUND AND AIMS: In March 2017, avelumab (anti–PD-L1) was approved for the treatment of metastatic MCC and has demonstrated meaningful survival benefit and durable response. We sought to investigate real-world clinical outcomes of avelumab-treated patients with aMCC (stage IIIB/IV) in US academic medical centers.
METHODS: A retrospective chart review study of patients with aMCC who initiated avelumab between March 1, 2017, and July 31, 2019 was conducted at 6 US academic medical centers across the 4 census regions. Eligible patients were followed through December 30, 2020. Descriptive analyses were conducted for demographics, clinical characteristics, and outcomes. Kaplan-Meier curves were constructed for real-world duration of response (rwDOR), real-world progression-free survival (rwPFS), overall survival (OS), and time-to-treatment discontinuation.
RESULTS: Ninety patients with aMCC received avelumab; median follow-up was 15.0 months (95% CI, 13.1-17.8). Median age was 68 years; most were male (58%) and White (93%). At avelumab initiation, 74 and 16 patients had stage IV and IIIB MCC, respectively. Primary tumor was most commonly on the lower limb (38%), with metastasis primarily to lymph nodes (67%) and lung (52%); 52% had visceral metastases. Approximately 42% and 26% had an ECOG PS of 2 and 3, respectively. Median duration of avelumab treatment was 13.5 months (95% CI, 6.4-30.6); 58% discontinued by end of follow-up. Avelumab-treated patients (n=90) had a real-world objective response rate (rwORR) of 73% (95% CI, 64-83), median rwPFS of 24.4 months (95% CI, 8.3-not reached [NR]), and median OS of 30.7 months (95% CI, 11.2-NR). Seventy-three patients (81%) received avelumab as first-line treatment and 17 (19%) as second-line or later; in these subgroups, rwORR (95% CI) was 75% (65-85) and 65% (39-90), respectively, median rwDOR (95% CI) was NR (NR) and 4.6 months (1.1-NR), median rwPFS (95% CI) was 36.1 months (9.3-NR) and 6.4 months (4.5-NR), and median OS (95% CI) was 41.7 months (10.2-NR) and 15.9 months (4.3-NR).Outcomes by stage at avelumab initiation will also be reported.
CONCLUSIONS: This real-world study of avelumab-treated patients with aMCC demonstrates high rwORR with durable responses and prolonged survival. Findings are consistent with results from pivotal clinical trials and recent observational studies.
