Open Access

Background: Methotrexate (MTX) remains the anchor drug in rheumatoid arthritis (RA) treatment, but is poorly tolerated or contraindicated in some patients. There is a wealth of data supporting the use of abatacept in combination with MTX, but data on alternative conventional synthetic disease-modifying antirheumatic drug (csDMARD) combinations with abatacept are scarce. Methods: In this post-hoc exploratory analysis, efficacy and safety data were extracted from abatacept RA studies in which combination with csDMARDs other than MTX was permitted: three interventional trials (ATTAIN, ASSURE, and ARRIVE) and one real-world study (ACTION). Patients with moderate-to-severe RA received abatacept in combination with MTX, hydroxychloroquine, sulfasalazine, azathioprine, or leflunomide for 6 months to 2 years according to the study design. Change from baseline in physical function (Health Assessment Questionnaire—Disability Index (HAQ-DI); all studies) and 28-joint Disease Activity Score (C-reactive protein) (DAS28 (CRP); ATTAIN, ARRIVE, and ACTION), American College of Rheumatology response rates (ATTAIN), and safety were assessed for individual and pooled csDMARD combinations for each trial. A meta-analysis was also performed on pooled data for HAQ-DI and DAS28 (CRP) across interventional trials. Results: Across all four studies, 731 patients received abatacept plus one non-MTX csDMARD (hydroxychloroquine n = 152; sulfasalazine n = 123; azathioprine n = 59; and leflunomide n = 397) and 2382 patients received abatacept plus MTX. Mean changes from baseline in HAQ-DI scores for abatacept plus MTX (all csDMARDs pooled) vs abatacept plus a non-MTX csDMARD were –0.54 vs –0.44 (ATTAIN), –0.43 vs –0.43 (ASSURE), and –0.39 vs –0.36 (ARRIVE). Mean changes from baseline in DAS28 (CRP) and ACR response rates were also similar with abatacept plus MTX or non-MTX csDMARDs. Data for individual non-MTX csDMARDs (pooled across studies) and real-world data were consistent with these findings. Rates of treatment-related adverse events and serious adverse events, respectively, for abatacept plus one non-MTX csDMARD vs abatacept plus MTX were 35.7% vs 41.7% and 2.4% vs 2.3% (ATTAIN), 58.0% vs 55.9% and 4.2% vs 1.7% (ASSURE), and 38.1% vs 44.3% and 0.6% vs 2.9% (ARRIVE). Conclusions: Abatacept in combination with non-MTX csDMARDs is clinically effective and well tolerated in patients with moderate-to-severe RA, providing similar benefits to those seen with abatacept plus MTX.

Biologics have transformed the treatment of immune-mediated inflammatory diseases such as rheumatoid arthritis (RA) and inflammatory bowel disease (IBD). Biosimilars—biologic medicines with no clinically meaningful differences in safety or efficacy from licensed originators—can stimulate market competition and have the potential to expand patient access to biologics within the parameters of treatment recommendations. However, maximizing the benefits of biosimilars requires cooperation between multiple stakeholders. Regulators and developers should collaborate to ensure biosimilars reach patients rapidly without compromising stringent quality, safety, or efficacy standards. Pharmacoeconomic evaluations and payer policies should be updated following biosimilar market entry, minimizing the risk of imposing nonmedical barriers to biologic treatment. In RA, disparities between treatment guidelines and national reimbursement criteria could be addressed to ensure more uniform patient access to biologics and enable rheumatologists to effectively implement treat-to-target strategies. In IBD, the cost-effectiveness of biologic treatment earlier in the disease course is likely to improve when biosimilars are incorporated into pharmacoeconomic analyses. Patient understanding of biosimilars is crucial for treatment success and avoiding nocebo effects. Full understanding of biosimilars by physicians and carefully considered communication strategies can help support patients initiating or switching to biosimilars. Developers must operate efficiently to be sustainable, without undermining product quality, the reliability of the supply chain, or pharmacovigilance. Developers should also facilitate information sharing to meet the needs of other stakeholders. Such collaboration will help to ensure a sustainable future for both the biosimilar market and healthcare systems, supporting the availability of effective treatments for patients.