Cost-efficiency modeling of conversion to biosimilar rituximab-based R-CHOP in diffuse large B-cell lymphoma in medicare.

[BACKGROUND] Rituximab-pvvr (Ruxience), -abbs (Truxima), and -arrx (Riabni) are biologic therapies approved by the United States Food and Drug Administration (FDA) as biosimilars to originator rituximab (Rituxan). Each is approved for the treatment of diffuse large B-cell lymphoma (DLBCL) in combination with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP). The objective of this study is to explore the cost-efficiency and budget-neutral expanded access of conversion to first-line biosimilar rituximab-based R-CHOP treatment in DLBCL in Medicare.

[METHODS] We developed a Medicare perspective simulation model of patients treated for DLBCL to estimate the potential cost-savings from converting originator rituximab to rituximab-pvvr, -abbs, -arrx, or a weighted average of these biosimilars. The target patient population was estimated using Medicare enrollment data and Surveillance, Epidemiology, and End Results Program (SEER) Cancer incidence rates in patients age ≥65 years. Costs were derived from 2025 Average Sales Price (ASP) files. Results include per-patient per-month (PPPM) cost savings (vs. originator), total monthly cost savings in the Medicare cohort, and number needed to convert (NNC) to biosimilar to fund additional 100 patient-months of R-CHOP treatment.

[RESULTS] In the base case strategy with 100% biosimilar conversion and an equally weighted proportion converting to each rituximab biosimilar, PPPM savings were $4,638, full cohort ( = 4,772) monthly savings were $22.1 m, and NNC was 69. In analyses assessing 100% conversion to rituximab-pvvr, -arrx, and -abbs, the PPPM savings were $5,036, $4,450, and $4,429; full cohort monthly savings were $24.0 m, $21.2 m, and $21.1 m; and NNC was 55, 76, and 77 respectively.

[CONCLUSION] In this first cost-efficiency and expanded access study of biosimilar rituximab in DLBCL in Medicare, we find that conversion to biosimilar-based R-CHOP can result in substantial cost savings relative to originator-based R-CHOP. These biosimilar-associated cost savings could be reinvested to treat thousands of additional DLBCL patients or fund other costs of care in Medicare, on a budget-neutral basis.