Safety and Immunogenicity of Rituximab Biosimilar GP2013 After Switch from Reference Rituximab in Patients with Active Rheumatoid Arthritis.

OBJECTIVES: Comparable clinical efficacy of the rituximab biosimilar GP2013 and reference rituximab (RTX) has been established in blinded randomized trials. However, when switching from a reference biologic to a biosimilar, potential safety implications are often an important consideration. Therefore, this study evaluated the safety of switching from reference RTX to rituximab biosimilar GP2013, compared with treatment continuation with reference RTX, in patients with rheumatoid arthritis (RA).

METHODS: In this multinational randomized, double-blind, parallel-group safety study, 107 patients with RA, who had previously received any duration of treatment with reference RTX as part of routine practice and who required a continuation of treatment, were randomized to receive either GP2013 or to continue reference RTX, both given with methotrexate and folic acid. Study assessments included incidence of hypersensitivity, infusion-related and anaphylactic reactions, immunogenicity (anti-drug antibodies [ADA]), and general safety.

RESULTS: Whether patients switched to GP2013 or continued reference RTX, the incidences of hypersensitivity (9.4% versus 11.1%, respectively) and infusion-related reactions (11.3% versus 18.5%, respectively) were similarly low. Only one patient in the reference RTX group developed ADA to rituximab after start of study treatment. No neutralizing ADAs were observed. ADAs were not associated with adverse events (AEs). No clinically meaningful differences in the rate of AEs were observed between treatment groups.

CONCLUSION: No safety risks were detected when patients switched from reference RTX to GP2013. The safety profiles of patients in both treatment groups were similar, although the study was not powered for statistical safety equivalence testing. This article is protected by copyright. All rights reserved.