Aims: We report efficacy and safety data from part A of the single-arm, phase 2, JAVELIN Merkel 200 trial of avelumab—anti–PD-L1 monoclonal antibody—in patients (pts) with mMCC and ≥2 y of follow-up.
Methods: Pts with mMCC and progressive disease (PD) on prior chemotherapy received avelumab 10 mg/kg IV Q2W until PD or intolerable adverse event (AE). Objective response rate (ORR), duration of response (DOR), and progression-free survival (PFS) were evaluated by independent review per RECIST v1.1; overall survival (OS) and AEs (per NCI CTCAE v4.0) were also evaluated.
Results: As of 26 Sep 2017, 88 pts were followed for a median of 29.2 mo (range 24.8-38.1). Median duration of treatment was 3.9 mo (range 0.5-36.3); treatment was ongoing in 10.2% of pts. The confirmed ORR of 33.0% (95% CI 23.3-43.8; complete response in 11.4%) remained unchanged from analyses at 1 y and 18 mo; responses were ongoing in 19 of 29 pts (12 pts with >2 y response duration). Median DOR had not been reached (range 2.8-31.8 mo; 95% CI 18.0-not estimable). Durable responses led to stable PFS rates (1-y: 29%; 18-mo: 29%; 2-y: 26%). Median OS was 12.6 mo (95% CI 7.5-17.1); 2-y OS rate was 36% (1-y: 50%; 18-mo: 39%). Clinical activity was observed across all pt subgroups. The AE profile remained consistent with previous analyses: 76.1% had a treatment-related AE (TRAE; grade ≥3 in 11.4%), 22.7% had an immune-related AE, and no treatment-related deaths occurred.
Conclusion: At ≥2 y of follow-up, avelumab shows continued durable responses, meaningful survival outcomes, and a manageable safety profile in pts with mMCC.
Results were presented in part at the 2018 ASCO Annual Meeting and published in the conference proceedings as abstract 9507. © 2018 American Society of Clinical Oncology, Inc. Reused with permission.