In January, the results from a study evaluating the pharmacokinetics, efficacy and safety of ABP 798, a treatment biosimilar to rituximab (Rituxan), were reported.1 This randomized, double-blind clinical trial compared ABP 798 with rituximab in treating patients with moderate to severe rheumatoid arthritis (RA). Rituximab is a CD20-directed cytolytic antibody approved for treating adults with moderate to severe RA, non-Hodgkin’s lymphoma, chronic lymphocytic leukemia, pemphigus vulgaris, granulomatosis with polyangiitis and microscopic polyangiitis.
During the study, 311 patients were enrolled and randomized to receive either ABP 798 (n=104), rituximab sourced from the U.S. (n=103) or rituximab sourced from the E.U. (n=104). Treatment was administered as an intravenous infusion at baseline. A second infusion was administered at Week 24.
The primary objective was pharmacokinetic similarity for ABP 798 compared with rituximab. The pharmacokinetic endpoints were area under the serum concentration–time curve and maximum serum concentration, with both results being within the pre-specified equivalence margin. The pre-specified equivalence in efficacy endpoint was measured by the Disease Activity Score 28-joint count C-reactive protein (DAS28-CRP) change from baseline at Weeks 24 and 48. The study also included a single transition for subjects on rituximab (U.S.) to ABP 798.
ABP 798 met the primary endpoint of pharmacokinetic similarity and established equivalent efficacy. ABP 798 also had a similar safety profile to rituximab, and its immunogenicity and safety were comparable with rituximab.