Primary analysis of post-marketing surveillance (PMS) data for avelumab maintenance therapy in patients (pts) with curatively unresectable urothelial carcinoma (UC) in Japan

BackgroundAvelumab maintenance therapy is the standard of care for advanced UC (aUC) that has not progressed after prior chemotherapy based on the JAVELIN Bladder 100 phase 3 (JB100) trial. We report primary analyses of PMS data for the safety and effectiveness of avelumab maintenance in pts with aUC in clinical practice in Japan.MethodsThis PMS is a multicenter, observational surveillance of pts with aUC without disease progression after prior chemotherapy who received ≥1 dose of avelumab from Feb 24, 2021, to Dec 7, 2021. Data on safety and effectiveness were collected from the start of avelumab therapy for ≤52 weeks and analyzed by descriptive statistics and Kaplan-Meier methods.ResultsThis analysis included 453 pts. Median age was 73.0 years (Q1-Q3, 68.0-78.0), including 180 pts (39.7%) older than 75 years. Primary tumor site was bladder in 244 pts (53.9%) and upper tract in 209 (46.1%). ECOG performance status was 0-1 in 436 pts (96.2%). Prior chemotherapy was gemcitabine + cisplatin in 267 pts (58.9%) and gemcitabine + carboplatin in 163 (36.0%). Response to chemotherapy was complete response in 47 pts (10.4%), partial response in 242 (53.4%), and stable disease in 149 (32.9%). Median observation period was 52.0 weeks (range, 3.6-52.0); at data cutoff (Mar 6, 2024), 128 pts (28.3%) remained on avelumab treatment and 184 pts (40.6%) received subsequent next-line treatment. Adverse drug reactions (ADRs) of safety specifications (SS; any grade) with avelumab occurred in 144 pts (31.8%), including grade ≥3 in 35 (7.7%); the most common any-grade ADRs of SS (≥5% of pts) were infusion reaction in 53 (11.7%) and thyroid dysfunction in 33 (7.3%). 32 pts (9.8%) had an ADR of SS that led to treatment discontinuation. Median overall survival (OS) was not reached and the 1-year OS rate was 77.9% (95% CI, 73.7-81.5).ConclusionsThe primary analysis of this PMS is the largest real-world data set of avelumab maintenance therapy in Asia, observing patients in clinical practice. The safety profile, tolerability, and effectiveness of avelumab maintenance therapy in this PMS were comparable to findings from JB100 and real-world studies from other countries.Clinical trial identificationthe University hospital medical information network clinical trials registry (UMIN-CTR: UMIN 43435).Editorial acknowledgementEditorial support was provided by Nucleus Global and was funded by Merck.Legal entity responsible for the studyMerck Biopharma Co., Ltd., Tokyo, Japan, an affiliate of Merck KGaA.FundingThis work was supported by Merck Biopharma Co., Ltd., Tokyo, Japan, an affiliate of Merck KGaA (CrossRef Funder ID: 10.13039/100009945) and was previously conducted under an alliance between Merck and Pfizer.DisclosureE. Kikuchi: Financial Interests, Personal, Advisory Role: Astellas Pharma, AstraZeneca, Bristol Myers Squibb-Ono Pharmaceutical, Chugai Pharmaceutical, Janssen, Merck, MSD, Pfizer; Financial Interests, Personal, Speaker’s Bureau: Astellas Pharma, AstraZeneca, Bayer, Bristol Myers Squibb-Ono Pharmaceutical, Chugai Pharmaceutical, Janssen, Kissei Pharmaceutical, Kyorin, Merck, MSD, Nippon Kayaku, Nippon Shinyaku, Pfizer, Sanofi, Taiho Pharmaceutical, Takeda, Kyowa Kirin International; Financial Interests, Institutional, Research Funding: Chugai Pharmaceutical, Kissei Pharmaceutical, Kyorin, Kyowa Kirin International, Nippon Kayaku, Nippon Shinyaku, Otsuka, Sanofi, Taiho Pharmaceutical, Takeda. T. Ito, M. Sato, M. Ogi, M. Morita, M. Kajita: Financial Interests, Personal, Full or part-time Employment: Merck Biopharma Co., Ltd., Tokyo, Japan, an affiliate of Merck KGaA. H. Nishiyama: Financial Interests, Personal, Speaker’s Bureau: Astellas Pharma, Merck, MSD, Olympus; Financial Interests, Personal, Research Funding: Chugai Pharmaceutical, Ono Pharmaceutical. All other authors have declared no conflicts of interest.