Real-world safety and effectiveness of MVASI in metastatic colorectal cancer patients in Canada

e15555 Background: MVASI is a biosimilar to the reference product, bevacizumab, and is the first biosimilar approved by Health Canada for the first-line (1L) treatment of metastatic colorectal cancer (mCRC). This study addresses the limited real-world evidence by describing the safety and effectiveness of MVASI as 1L therapy in mCRC. Methods: Retrospective data were collected in two waves of sites across Canada, at least 1 year (wave 1) or 2 years (wave 2) after commercial availability of MVASI at each site. Adult patients treated with ≥ 1 MVASI cycles as their 1L therapy for mCRC were included. Baseline demographic and clinical characteristics were collected 6 months prior to MVASI initiation (index date). Medical history, adjuvant treatment, and CRC diagnosis were collected within 5 years of pre-index date. Outcomes were gathered between index and chart review dates. Results: Among the 75 patients in wave 1, 36 (48.0%) were male and the median age was 62 years. Of the 164 patients in wave 2, 98 (59.8%) were male and the median age was 67 years. Most patients in wave 1 (42/69; 60.9%) and wave 2 (87/141; 61.7%) had a RAS mutation. The median time from mCRC diagnosis to MVASI initiation among wave 1 and 2 patients was 3.1 (IQR [2.1, 4.2]) and 2.3 months (IQR [1.6, 3.7]), respectively. At least one safety event of interest (EOI) was recorded for 26/75 (34.7%) wave 1 and 70/164 (42.7%) wave 2 patients (Table 1). The median progression free survival (PFS) for wave 1 and 2 patients were 9.47 and 21.38 months, respectively. Median overall survival (OS) for wave 1 patients was not estimable and was 26.45 months for wave 2 patients. Conclusions: In this real-world study, mCRC patients treated with 1L MVASI were generally representative of the Canadian mCRC population treated with 1L bevacizumab. Compared with clinical trials of MVASI and reference bevacizumab, the EOI profile and the OS data are similar, but lower rates of individual EOIs are observed in this real-world setting. The shorter PFS observed in wave 1 may be due to higher rates of comorbidities at baseline and longer time from mCRC diagnosis to index. [Table: see text]