Real-world use and acceptance of biosimilar monoclonal antibodies of rituximab in oncology practice in the USA.

Aim: To describe treatment patterns and patient and provider characteristics associated with the recently introduced biosimilar rituximab-pvvr. Methods: This retrospective analysis included adult patients with one or more claims for rituximab-pvvr, with an index date of 23 January 2020 and a study period covering 1 January 2019-31 July 2020. Results: Of 249 patients included, the most common rituximab-pvvr indications were non-Hodgkin's lymphoma (77.5%) and chronic lymphocytic leukemia (11.2%). Some patients with non-Hodgkin's lymphoma (42.5%) and chronic lymphocytic leukemia (39.3%) switched to rituximab-pvvr from the reference product or another rituximab biosimilar. Most patients were aged ≥65 years (63.5%) and were male (54.6%). Most (59.0%) rituximab-pvvr prescribers practiced in the south of the USA. Conclusion: Utilization occurred in approved and extrapolated indications. These preliminary findings suggest switching between reference product and rituximab biosimilars; rituximab-pvvr combination regimens are being adopted in real-world oncology practice.