BRIGHTON, ENGLAND – Rituximab is an effective treatment for established rheumatoid arthritis in routine clinical practice, with response predicted by baseline disease activity and functional status, based on data from the British Society for Rheumatology Biologics Register.
Rituximab has been licensed for use in combination with methotrexate since 2006 in both the United States and the United Kingdom, and is generally used after treatment failure with traditional nonbiologic disease-modifying antirheumatic drugs (DMARDs) and at least one anti–tumor necrosis factor–alpha (anti-TNF-alpha) agent.
Two analyses, presented at the annual meeting of the British Society for Rheumatology (BSR) by Moetaza Soliman and her associates, highlighted the real-world use of the biologic agent in patients with severe, active rheumatoid arthritis.
Coauthors of the research included the two principal investigators of the BSRBR – Dr. Deborah Symmons and Dr. Kimmie Hyrich, both of the arthritis research U.K. epidemiology unit at the University of Manchester (England).
"Rituximab has been shown to have good efficacy in clinical trials," said Ms. Soliman, a doctoral researcher at the university. Whether the same can be said in everyday practice was the focus of the first evaluation of data from the BSR Biologics Register (BSRBR).
The overall efficacy of rituximab was examined in 550 patients treated with the drug up until a data cutoff of October 2010. The analysis involved all patients who were treated with the biologic agent, and looked at clinical and patient-reported outcomes 6 months after treatment was started.
The mean age of patients was 59 years, 78% were female, and the mean disease duration was 15 years. One-third of the cohort was seronegative for rheumatoid factor.
The majority (84%) of patients had been treated with anti-TNF therapy, with 53% failing one, 37% two, and 6% three prior anti-TNF drugs.
The most common nonbiologic DMARD used was methotrexate (52%), with some patients receiving up to seven DMARDs.
According to European League Against Rheumatism criteria, 43% of patients showed a "moderate" response to rituximab after 6 months, despite all their prior therapies, with 16% even achieving a "good" response. However, the remaining 41% did not respond to treatment with rituximab.
The mean 28-joint disease activity score (DAS28) at baseline was 6.2 for the whole cohort, which fell to 4.8 at 6 months, a mean change of –1.4. Health Assessment Questionnaire (HAQ) scores also fell, by a mean of –0.1 over the same time period, indicating improved physical function.
Patients who had not received prior anti-TNF therapy (16% of the cohort) appeared to fare better than those who had received such treatment before rituximab, with a mean change in DAS28 of –1.7 compared with –1.3 for anti-TNF failures (P = .05).
The second analysis, presented at a poster session, looked more specifically for baseline factors that might predict which patients were likely to have a better response than others to rituximab.
The analysis involved 463 patients and found that those with higher baseline DAS28 scores were significantly more likely to respond to rituximab than those with lower DAS28 scores.
In addition, rheumatoid factor–positive patients were more likely to achieve disease remission than seronegative patients, but those with higher functional disability (that is, higher HAQ scores) or higher baseline DAS28 scores were less likely to achieve remission by 6 months.
"Rituximab is proven effective in the routine management of RA patients," Ms. Soliman commented. "Response to rituximab was influenced by baseline disease activity and baseline physical function."
The BSRBR is funded by a grant from the BSR. The BSR receives funding from Abbott Laboratories, Biovitrum/SOBI, Merck Sharp & Dohme, Pfizer, Roche, and UCB. This income finances a separate contract between the BSR and the University of Manchester that provides and runs the BSRBR. All decisions concerning data analysis, interpretation, and publications are made autonomously of any industrial contribution. Ms. Soliman said she had no relevant financial disclosures.