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. Lay abstract A biosimilar is a biological medication that is highly similar in structure and function to a biological medication already approved by the US FDA - the 'original biologic'. The first biosimilars approved to treat certain blood cancers have become available in the USA. This study examined how a recently introduced rituximab biosimilar was being utilized, looking at patient and physician characteristics from a medical and prescription insurance claims database. This study did not examine the safety or effectiveness of this medication. While initial data are limited, the biosimilar, rituximab-pvvr, appears to be utilized to treat the same types of cancer as the original biologic, rituximab. The biosimilar was most frequently prescribed for non-Hodgkin's lymphoma and chronic lymphocytic leukemia.