407P - A post-marketing surveillance of the real-world safety and effectiveness of avelumab in patients with curatively unresectable Merkel cell carcinoma in Japan

Background

Avelumab was conditionally approved in Japan in Sep 2017 for the treatment of patients with curatively unresectable Merkel cell carcinoma (MCC). A mandated all-case surveillance was conducted to confirm the real-world safety and effectiveness of avelumab in Japan. We report the final analysis of this post-marketing surveillance (PMS).

Methods

This multicenter, non-comparative, prospective, observational study enrolled all patients who received at least one dose of avelumab since Nov 2017 and collected case report forms (CRFs) of all patients who started treatment by Oct 2019.

Results

As of Sep 2021, 152 patients from 86 sites were enrolled, and CRFs were collected from 78 patients. Of the 75 patients (53 sites) who met the analysis criteria, the median age was 77.0 years (range, 42-95). The median number of total doses was 11.0 doses (range, 1–27); 33.3% (n=25) of patients were still on treatment and the median OS was 13.3 months (95% CI: 10.6-NR). The main reasons for treatment discontinuation were disease progression (33.3%; n=25), death (12.0%; n=9) and adverse events (9.3%; n=7). The most frequently reported adverse drug reactions of safety specification (ADRs) were infusion reactions (IRs; 28.0%; n=21), thyroid dysfunction (9.3%; n=7) and hepatic function disorders (5.3%; n=4). The observed grade 3-4 ADRs were IRs (4.0%; n=3), nerve disorders, interstitial lung disease, type 1 diabetes (T1D), and myositis (each 1.3%; n=1). No grade 5 ADRs were reported. Except for T1D, all grade 3-4 ADRs improved or recovered. No effect of ADR onset on the duration of treatment was observed.

Conclusions

This PMS provides the first real-world evidence for avelumab treatment of patients with curatively unresectable MCC in East Asia. Our findings will further support the safe administration of avelumab and optimize treatment strategies for MCC.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Merck Biopharma Co., Ltd.

Funding

This study was sponsored by Merck Biopharma Co., Ltd., Tokyo, Japan, an affiliate of Merck KGaA (CrossRef Funder ID: 10.13039/10000994), as part of an alliance between Merck and Pfizer.

Disclosure

N. Yamazaki: Financial Interests, Personal, Advisory Board: Ono Pharmaceutical Co., Ltd., Chugai Pharmaceutical Co., Ltd., Merck & Co., Inc.; Financial Interests, Personal, Invited Speaker: Ono Pharmaceutical Co., Ltd., Bristol Myers Squibb Company, Novartis, Merck & Co., Inc.; Financial Interests, Personal and Institutional, Research Grant: Ono Pharmaceutical Co., Ltd., Bristol Myers Squibb Company, Novartis, Amgen Inc. Y. Kiyohara: Financial Interests, Personal, Research Grant: Ono Pharmaceutical Co., Ltd., Merck & Co., Inc., Takara Bio Inc., Bristol Myers Squibb Company, Amgen Inc., Sanofi K.K.; Financial Interests, Personal, Invited Speaker: AstraZeneca K.K., Ono Pharmaceutical Co., Ltd., Otsuka Pharmaceutical, Hollister Incorporated, Eli Lilly Japan K.K., Novartis Japan, Bristol Myers Squibb Company, Maruho Co., Ltd., Merck KGaA, Janssen Pharmaceutical K.K. H. Uhara: Financial Interests, Personal, Advisory Board: Merck Biopharma Co., Ltd., Ono Pharmaceutical, Novartis, MSD, Kyowa Hakko Kirin Company, Bristol Myers Squibb K.K.; Financial Interests, Personal, Speaker’s Bureau: Merck Biopharma Co., Ltd., Ono Pharmaceutical, Novartis, MSD, Janssen Pharmaceutical K.K, Kyowa Hakko Kirin Company, Limited, Mitsubishi Tanabe Pharma, Sun Pharma, Bristol Myers Squibb K.K., TAIHO Pharmaceutical Co., Ltd.; Financial Interests, Personal and Institutional, Research Grant: Ono Pharmaceutical, TAIHO Pharmaceutical Co., Ltd., Kyowa Hakko Kirin Company, Limited, Mitsubishi Tanabe Pharma, Eisai, AbbVie, Maruho, Daiichi Sankyo, Tsumura & Co., Sun Pharma. All other authors have declared no conflicts of interest.