Effectiveness and safety of rituximab-pvvr versus originator rituximab for rheumatoid arthritis in the Veterans Health Administration.

OBJECTIVE

Real-world comparisons of rituximab biosimilars with originator rituximab have largely focused on oncology, with limited evidence in RA. This gap is particularly pertinent to the Veterans Health Administration (VHA), where patients with RA are older and have greater comorbidity. We evaluated the effectiveness and safety of rituximab-pvvr vs originator rituximab in veterans with RA by (i) describing treatment patterns, (ii) assessing effectiveness, (iii) evaluating adverse events and (iv) identifying reasons for switching back to the originator after initiating the biosimilar.

METHODS

We conducted a retrospective cohort study using VHA Pharmacy Benefits Management data among veterans aged ≥18 years who received originator rituximab or rituximab-pvvr for RA between 1 March 2020 and 31 August 2023. Effectiveness outcomes (e.g. prednisone use) and safety outcomes (e.g. infection) were assessed using regression analyses within entropy-balanced subgroups of incident originator and biosimilar users.

RESULTS

A total of 1717 veterans with RA received originator rituximab or rituximab-pvvr during the study period. Among 1074 incident users, there were no significant differences between originator and biosimilar groups in effectiveness [e.g. discontinued prednisone use: risk difference (RD) = 0.05; 95% CI -0.04-0.14] or safety (e.g. infection-related hospitalizations or emergency department visits: RD = -0.02; 95% CI -0.08-0.05).

CONCLUSION

We found no clinically meaningful differences in the effectiveness or safety of rituximab-pvvr compared with originator rituximab among incident users with RA. These real-world findings support the clinical use of rituximab-pvvr and may improve clinician and patient confidence in biosimilar adoption.