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B-Cell-Poor RA Responds Better to Tocilizumab Than to Rituximab
Key clinical point: B-cell-poor status appears to identify RA patients who are more likely to respond to tocilizumab than to rituximab.
Major finding: B-cell-poor patients treated with tocilizumab were twice as likely as those treated with rituximab to achieve Clinical Disease Activity Index improvement of at least 50% from baseline and Clinical Disease Activity Index major treatment response at 16 weeks (46.3% vs. 23.7%).
Study details: The randomized, open-label, phase 4 R4-RA trial.
Disclosures: R4-RA is funded by the National Institute of Health Research Efficacy and Mechanism Evaluation program. Dr. Pitzalis and some of the other study authors reported financial relationships with Roche/Genentech, which markets tocilizumab and rituximab, and other pharmaceutical companies.
Pitzalis C et al. Arthritis Rheumatol. 2019;71(suppl 10), Abstract 2911.
With the availability and widespread use of non-TNF biologics for RA, the question of appropriate biologic choice to avoid delays in optimal therapy, as well as excessive spending, has become increasingly important. In this study presented at the 2019 American College of Rheumatology scientific meeting, the authors looked at B-cell infiltration of the synovium as a marker for response to rituximab treatment. Participants had previously failed DMARDs and at least one TNF inhibitor. Patients with synovial biopsies that were “B-cell poor” had a better response to tocilizumab (based on CDAI improvement), compared with rituximab. Of note, in patients with B-cell-rich synovial biopsies, rituximab and tocilizumab did not have significantly different efficacies. Synovial biopsy may be of some utility in providing biomarkers for treatment response in RA, though the mechanism is not yet clear.— Arundathi Jayatilleke, MD