Efficacy and safety results from a randomized double-blind study comparing proposed biosimilar ABP 798 with rituximab reference product in subjects with moderate-to-severe rheumatoid arthritis

Abstract

Background/objectivesABP 798 is a proposed biosimilar to the originator biologic rituximab, an anti-CD20 monoclonal antibody. This comparative clinical study evaluated the pharmacokinetics (PK), safety, and efficacy of ABP 798 versus rituximab reference product (RP) in patients with moderate-to-severe rheumatoid arthritis (RA).MethodsAdults with moderate-to-severe RA with an inadequate response or intolerance to other disease-modifying anti-rheumatic drugs including 1 or more tumor necrosis factor inhibitor therapies (n = 311) received ABP 798, US-sourced rituximab RP (rituximab US), or EU-sourced rituximab RP (rituximab EU) (1000 mg, 2 weeks apart). At week 24, ABP 798- or rituximab EU-treated subjects received a second dose of the same treatment, while rituximab US-treated subjects transitioned to receive ABP 798. The key efficacy endpoint was DAS28-CRP change from baseline at week 24. Other efficacy endpoints included DAS28-CRP at other time points; ACR20, ACR50, and ACR70 criteria; and hybrid ACR. The rituximab RP groups were pooled for all efficacy endpoints since PK equivalence had been established between rituximab US and rituximab EU.ResultsClinical equivalence between ABP 798 and rituximab RP was established as the 90% confidence interval for DAS28-CRP change from baseline at week 24 fell within the prespecified equivalence margin (− 0.6, 0.6). Safety and immunogenicity profiles of ABP 798 were comparable across treatment groups and not affected by single transition from RP to ABP 798.ConclusionsClinical equivalence in terms of efficacy, safety, and immunogenicity was established between ABP 798 and rituximab RP in this comparative clinical trial in patients with moderate-to-severe RA.Key Points• ABP 798 provided similar efficacy as rituximab reference product (RP) in patients with moderate-severe rheumatoid arthritis.• The safety and immunogenicity profiles for ABP 798 were similar to those for the rituximab RP.• The single transition from rituximab RP to ABP 798 did not show differences in efficacy, safety, or immunogenicity.