Abstract 254P
Background
Trastuzumab (tras)-anns (KANJINTI™) is one of the first biosimilars of reference product (RP) Herceptin® approved in the European Union (EU) in May 2018, also approved in the United States in June 2019, for treatment of human epidermal growth factor receptor 2-positive (HER2+) early and metastatic breast cancer (BC) as well as metastatic gastric cancer. Study objectives were to define real-world characteristics of BC patients (pts) receiving tras-anns, their prior tras treatment patterns, and tras-anns safety.
Methods
This was a single arm, observational, serial chart review of adult BC pts receiving/having received tras-anns in the neo/adjuvant or metastatic setting, including maintenance. Data collected covered the previous treatment, after enrollment, and the follow up (f/u) period from tras-anns initiation to withdrawal of consent, death, lost to f/u, entry into interventional trial, or end of study (12 months after last patient enrolled), whichever occurred first.
Results
The study enrolled 488 pts who received tras-anns at 42 sites in 7 EU countries. Most pts were women (99%) of mean age 56.7 years. Distribution across disease stages at tras-anns initiation was: 0 [ductal carcinoma in situ HER2+] (0.8% [n=3 adjuvant, n=1 neoadjuvant]); I (15.6%); II (28.9%); III (15.2%); IV (30.7%); unknown/missing (8.8%). Overall, 144 (29.5%) pts switched to tras-anns from another tras product, most from RP (47.9% IV; 15.3% SC). Two thirds of switchers had stage IV disease (65.3%) and were treated in metastatic setting (66.7%). Tras-anns use was comparable across adjuvant, neoadjuvant, and metastatic settings (∼33% each). In the metastatic setting (n=162), most pts received tras-anns 1st line (111, 68.5%). Common reasons for discontinuation (244, 50.0%) included switching to another tras-anns biosimilar (85, 34.8%), switching to RP (38, 15.6%), or disease progression (28, 11.5%). Treatment-emergent adverse events (TEAEs) of interest were reported in <10% of tras-anns new user or switcher pts.
Conclusions
Real-world experience patterns suggest tras-anns was used as initial treatment across treatment settings and disease stages. Few new users or switchers reported TEAEs of interest.
Clinical trial identification
Editorial acknowledgement
Kathryn Miles, PhD, of BioScience Communications, New York, NY, provided medical writing support (on behalf of Amgen Inc.).
Legal entity responsible for the study
Amgen Inc.
Funding
Amgen Inc.
Disclosure
L. Wyrwicz: Financial Interests, Personal, Speaker’s Bureau: Amgen Inc.; Financial Interests, Personal, Advisory Role: Amgen Inc. C.A. Rodríguez Sanchez: Financial Interests, Personal, Speaker’s Bureau: Amgen Inc. S. Lewis: Financial Interests, Personal, Stocks/Shares: Amgen Inc.; Financial Interests, Personal, Full or part-time Employment: Amgen Inc. D. Sandschafer: Financial Interests, Personal, Full or part-time Employment: Amgen Inc.; Financial Interests, Personal, Stocks/Shares, Amgen Inc.: Amgen Inc.; Financial Interests, Personal, Expert Testimony: Amgen Inc. T. San: Financial Interests, Personal, Other, Expert: Novartis; Financial Interests, Personal, Other, Consultant: Eisai. All other authors have declared no conflicts of interest.