Low-Dose Biosimilar Rituximab Is Effective in Treating RA

Rituximab has previously been shown to be effective at doses of 1000 mg in treating patients with rheumatoid arthritis (RA) who had previously received other biologic agents. Research presented at the European League Against Rheumatism (EULAR)'s Annual European Congress of Rheumatology demonstrates that using lower doses of biosimilar rituximab—which may provide a substantial cost savings—is also effective.

A Russian study, ALTERRA, demonstrated that using low-dose biosimilar rituximab as first-line therapy for patients with RA is feasible.¹ The multicenter, randomized, double-blind, placebo-controlled, phase 3 study investigated the use of BCD-020, a rituximab biosimilar being developed by Biocad, at a dose of 600 mg plus methotrexate, versus placebo plus methotrexate, in biologic-naïve patients with RA. In total, there were 107 patients in the rituximab arm and 52 patients in the placebo arm.

At week 24, an improvement of 20%, measured by American College of Rheumatology standards (ACR20), was achieved by 65.69% of patients in the rituximab arm and 29.41% of patients in the placebo arm (P = .00005). At week 52, among those receiving biosimilar rituximab, 84.5% achieved ACR20, 54.6% achieved ACR50, and 29.9% achieved ACR70.

Patients receiving rituximab also had more pronounced decreases in disease activity score as measured by a count of 28 joints with erythrocyte sedimentation rate and in scores on the Health Assessment Questionnaire-Disability Index.

The 600-mg dose of rituximab had a favorable safety profile, with no significant difference from the placebo group.

A second study reported that an even lower dose of biosimilar rituximab, which could represent a cost-saving approach for resource-poor practices, is also effective in treating patients with RA who are refractory to conventional disease-modifying antirheumatic drugs (DMARDs).²

Researchers reported findings from an open-label study in a single center in Ahmedabad, India, that investigated biosimilar rituximab in biologic-naïve, DMARD-refractory patients with RA. Patients were assigned to receive either 4 weekly doses of 100 mg of rituximab or a single dose of 100 mg of rituximab, and were assessed at week 24.

The 4-dose arm comprised 14 patients, and the single-dose arm comprised 13 patients. At week 24, 4 patients in the 4-dose arm and 3 patients in the single-dose arm achieved remission by EULAR standards, 4 patients in each arm achieved EULAR low disease activity, and 11 and 9 patients, respectively, achieved a EULAR good response.

The investigators concluded that a single dose of 100 mg was just as effective as 4 doses in treating DMARD-refractory patients with RA.

Reference

1. Mazurov V, Denisov L, Gordeev I, et al. Results of the ALTERRA clinical trial—the efficacy of the alternative dosing regimen for rituximab biosimilar in bDMARDS naïve patients with rheumatoid arthritis. Presented at the European League Against Rheumatism’s Annual European Congress of Rheumatology, June 13-16, 2018; Amsterdam, Netherlands. SAT0206 doi: 10.1136/annrheumdis-2018-eular.2300.

2. Jain NS, Pandya S, Shukla D, Srivastava P. Efficacy and B-cell depletion with very low dose rituximab (biosimilar) in sero-positive DMARD-resistant rheumatoid arthritis: a 24-week study. Presented at the European League Against Rheumatism’s Annual European Congress of Rheumatology, June 13-16, 2018; Amsterdam, Netherlands. AB0458. doi: 10.1136/annrheumdis-2018-eular.6390.