Cost-effectiveness analysis of bevacizumab biosimilars for metastatic colorectal cancer: A comparative study using real-world data.

9 Background: MVASI (Amgen) and Zirabev (Pfizer) are two of the earliest bevacizumab biosimilars approved for the first-line treatment of metastatic colorectal cancer (mCRC). While the introduction of biosimilars present an opportunity to alleviate the financial toxicity owing to the escalating costs of novel biologics, biosimilars should be comparatively assessed against the reference biologic in a real-world setting to confirm that they are indeed cost-saving or cost-effective after implementation. In this study, we aimed to confirm and quantify the real-world cost-savings of MVASI and Zirabev relative to originator bevacizumab (Avastin) for patients with mCRC. Methods: We conducted a population-based, retrospective cohort study in Ontario, Canada, where originator and biosimilar bevacizumab are universally publicly funded. Capturing the entire population of Ontario, we assessed all mCRC patients who received originator bevacizumab between January 1, 2008, and August 11, 2019, or biosimilar bevacizumab between August 12, 2019, and March 31, 2021. Biosimilar cases and originator bevacizumab controls were matched 1:4 using propensity score methods to adjust for differences at baseline. We calculated 1-year total patient-level costs (in Canadian dollars) and effects (in life years and quality-adjusted life years (QALY)) from the public health payer’s perspective. The primary outcomes for estimating cost-effectiveness were incremental net monetary benefit (INMB) and incremental net health benefit (INHB), calculated at willingness-to-pay (WTP) thresholds ranging from $50,000-200,000 per life year gained. Sensitivity analyses included a subgroup analysis by biosimilar type (MVASI/Zirabev) and an analysis using a 2-year time horizon. Results: The final propensity score matched cohort included 747 biosimilar cases and 2,945 controls. Bevacizumab biosimilars were associated with an incremental cost of -$6,379 (95% confidence interval (CI): -9,417, -3,537) (i.e., cost-saving) and an incremental effect of 0.0 (95% CI: -0.02, 0.02) life years gained and -0.01 (95% CI: -0.03, 0) QALY gained. INMB and INHB estimates indicated that biosimilar bevacizumab is cost-effective at all WTP thresholds assessed, with results remaining consistent across our biosimilar type subgroups and 2-year sensitivity analyses. Conclusions: Bevacizumab biosimilars demonstrated real-world cost-savings while providing similar survival benefit as originator bevacizumab, confirming the initial expectations of their implementation.