The long-term similarity of the rituximab biosimilar CT-P10 and 2 approved rituximab reference products has been demonstrated for up to 48 weeks in patients with rheumatoid arthritis (RA), according to results of a multinational, randomized, double-blind, phase 3 trial published in BioDrugs.

The investigators sought to examine the long-term clinical outcomes of extended treatment with CT-P10 compared with that of 2 rituximab reference products, one sourced from the United States and one source from Europe, in patients with active RA. Efficacy, pharmacodynamics, pharmacokinetics, safety, and immunogenicity of the products were studied. All participants received up to 2 courses of CT-P10, the US reference product, or the European reference product, along with methotrexate. Efficacy end points included the 28-joint count Disease Activity Score (DAS28) and the American College of Rheumatology (ACR) response rates.

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A total of 372 patients were randomly assigned to the study drug, of whom 88.7% completed the second course of treatment. The mean change in DAS28 using C-reactive protein from baseline to 48 weeks was comparable in the CT-P10 and combined rituximab groups (–2.7 and –2.6, respectively). Furthermore, ACR20, ACR50, and ACR70 response rates at 48 weeks revealed no differences between the treatment groups. Overall, 80.6%, 55.4%, and 31.7% of participants in the CT-P10 group attained ACR20, ACR50, and ACR70, respectively, compared with 79.8%, 53.9%, and 33.7%, of participants in the combined reference groups.

Comparable improvements in the Health Assessment Questionnaire Disability Index, as well as all medical outcomes (physical and mental health) on the Short Form 36-Item Health Survey, were observed in all groups. Antidrug antibodies were detected in 4.9%, 9.4%, and 8.6% of patients in the CT-P10, US reference product, and European reference product groups, respectively, at 48 weeks. Moreover, similar pharmacodynamic, pharmacokinetic, and safety profiles were reported with biosimilar CT-P10 and innovator rituximab.

The investigators concluded that the results of this study provide evidence for the long-term use of CT-P10 with respect to efficacy and safety in clinical practice, which supports the recent approval of biosimilar CT-P10 for the treatment of RA as well as other CD20+ B-cell-related disorders.

Reference

Suh C-H, Yoo D-H, Berrocal Kasay A, et al. Long-term efficacy and safety of biosimilar CT-P10 versus innovator rituximab in rheumatoid arthritis: 48-week results from a randomized phase III trial. BioDrugs. 2019;33(1):79-91.