Studies Suggest Similar Risks for Biologics vs. Conventional Therapies for Rheumatoid Arthritis

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Two new studies delving into the relative safety of biologic drugs prescribed for rheumatoid arthritis (RA) have concluded that real-world applications of abatacept and tumor necrosis factor inhibitors (TNFi’s) are comparable to more conventional therapies in their associated risk of serious infections.

Triple Therapy

One study, in Arthritis Care & Research, found the risk of serious infection, in­cluding all bacterial and opportunistic infections requiring hospitalization or herpes zoster, wasn’t substantially different between TNFi plus methotrexate (MTX) therapy and triple therapy (MTX, hydroxychloroquine and sulfasalazine).¹

The study was led by Seoyoung C. Kim, MD, ScD, MSCE, associate professor of medicine, Harvard Medical School, Boston. “While we still need to discuss other potential adverse events with our patients, at least our data provide real-world evidence on the risk of infection—one of the most common safety events—from the direct comparison,” she says. Dr. Kim is also a member of the Division of Pharmaco­epidemiology and Pharmacoeconomics, and of the Division of Rheumatology, Immunology and Allergy at Brigham and Women’s Hospital, Boston.

Dr. Kim’s cohort study, based on claims data from Truven MarketScan, included 45,208 TNFi plus MTX initiators and 1,387 triple therapy initiators. The study calculated an incidence rate of 2.46 per 100 person-years for any serious infection in the TNFi plus MTX cohort and an incidence rate of 2.03 per 100 person-years in the triple therapy cohort. Using propensity score-based fine stratification and weighting, the researchers calculated a hazards ratio (with a 95% confidence interval) of 1.23 (0.87–1.74) for TNFi plus MTX versus triple therapy for any serious infection.

Abatacept

The second study, published in Arthritis Research & Therapy, found that abatacept was “well tolerated and did not result in an overall increased risk of malignancies, in­fections or autoimmune diseases” compared with other biologic disease-modifying anti-rheumatic drugs (bDMARDs) or conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDs).²

Senior author Kaleb Michaud, PhD, associate professor of immunology and rheumatology, University of Nebraska Medical Center, Omaha and co-director of FORWARD, the National Databank for Rheumatic Diseases, Wichita, Kan., says his team worked on the observational study for more than a decade.

The study reviewed FORWARD-registered RA patients, including 1,496 who initiated abatacept, 3,490 who initiated another bDMARD, and 1,520 who initiated a csDMARD. Based on the hazard ratios, patients on abatacept had a lower risk of hospitalized infections, although the analysis yielded wide confidence intervals in comparisons to other bDMARDs (0.37 [0.18–0.75]) and to csDMARDs (0.31 [0.09–1.05]). The comparisons found no statistically significant difference in the risk of malignancies or psoriasis, albeit again with wide confidence intervals.