A descriptive analysis of real-world oncology biosimilar use in Japan
Creators: name: Roth, Joshua A
name: Rahshenas, Makan
name: Nowacki, Grégoire
name: Masurkar, Nihar
name: Shelbaya, Ahmed
name: Tajima, Kentaro
name: Dorman, Stephanie
name: Ono, Chiho
Publisher: name: Taylor & Francis
Year: 2024
Subjects: subject: Medicine
subject: Pharmacology
subject: Biotechnology
subject: Ecology
subject: FOS: Biological sciences
subject: Immunology
subject: FOS: Clinical medicine
subject: Cancer
subject: Hematology

description: <b>Aim:</b> To describe patient and treatment characteristics associated with bevacizumab BS-Pfizer, rituximab BS-Pfizer and trastuzumab BS-Pfizer and their reference products in Japan. <b>Methods:</b> This retrospective observational study used an administrative claims database to identify patients with ≥1 biosimilar or reference product prescription from 2019 to 2022 for approved indications. Descriptive statistics were calculated. <b>Results:</b> Overall, 14–39% of biosimilar-prescribed patients initiated therapy with reference products. Biosimilar utilization significantly increased from 2019 to 2022. The most-commonly prescribed concomitant class of therapy with biosimilars was antineoplastic therapy. <b>Conclusion:</b> Reference products were most frequently prescribed among the Japanese cohorts, but substantial and increasing proportions received biosimilars over time. Future studies should extend our initial insights to assess biosimilar clinical outcomes in Japanese settings. This study examines the adoption of cancer biosimilar therapies in Japan from 2019 to 2022. Cancer biosimilars are complex treatments that closely resemble established cancer therapies already available in Japan. We looked into the characteristics of patients receiving three specific biosimilars – bevacizumab BS-Pfizer, rituximab BS-Pfizer and trastuzumab BS-Pfizer. We also investigated where patients received biosimilar treatment, other therapies they received alongside biosimilars and the proportion of patients using these therapies each year during the study. Our analysis utilized data from the ‘Medical Data Vision’ database, which records care provided in hospitals across Japan. We analyzed patient demographics and treatment patterns, and compared different groups using statistics to identify significant differences. Notably, we observed that between 14 and 39% of patients initially started treatment with the original version of the drug on the market, known as the ‘reference product,’ before switching to the biosimilar. Furthermore, our findings revealed a significant increase in the use of biosimilars each year during the study period. Biosimilars were most-commonly used alongside chemotherapy drugs. These initial findings shed light on the patient population using cancer biosimilars in Japan and the treatment contexts in which they are utilized. Future research should delve deeper into aspects such as cost of care, patient survival, side effects and other pertinent factors related to the use of biosimilars in cancer care in Japan. The use of oncology biosimilars in clinical practice in Japan is limited, at least partly, by the lack of evidence demonstrating real-world outcomes in Japanese patients. This retrospective observational study provides descriptive insights into the real-world use of bevacizumab, rituximab and trastuzumab biosimilars in Japan for colorectal cancer and non-small-cell lung cancer, B-cell non-Hodgkin's lymphoma and HER2-positive breast and gastric cancers, respectively. We observed significant increases in biosimilar utilization over time from 2019 to 2022. Across indications, from 14 to 39% of biosimilar-prescribed patients switched to the biosimilar after initiating therapy with the corresponding refence product. The most commonly prescribed concomitant class of therapy with biosimilars was antineoplastic therapy across each setting. This study has several limitations that should be noted, including that the Medical Data Vision hospital-based claims database has missing data for some variables, lacks detailed diagnosis and prognosis data (histology, Eastern Cooperative Oncology Group performance status, disease severity, etc.) and does not record deaths that occur outside the hospital. Initial real-world insights in Japan demonstrate comparable patient characteristics, treatment patterns and treatment duration between bevacizumab, rituximab and trastuzumab biosimilar and originator-treated patients.