A retrospective, multinational, cross-sectional survey of real-world outcomes for patients with axial spondyloarthritis receiving subcutaneous infliximab

Abstract Background CT-P13 SC, a new subcutaneous (SC) formulation of biosimilar infliximab (IFX), was approved by the European Medicines Agency in 2020 for the treatment of radiographic axial spondyloarthritis (axSpA) in adult patients. The present study aimed to assess the real-world outcomes of CT-P13 SC (SC IFX) as a treatment for both radiographic and non-radiographic axSpA. Methods Data were drawn from the Adelphi Real World axSpA Disease Specific Programme™, a cross-sectional survey with retrospective data collection in France, Germany, Italy, Spain, and the UK between June 2023 and June 2024. Rheumatologists and their patients with axSpA completed questionnaires on patient demographics, clinical characteristics, and treatment satisfaction. Outcomes for patients on SC IFX were analyzed, with additional evaluations based on baseline characteristics and treatment patterns. Such outcomes were also compared with patients receiving other advanced therapies, including biologics and Janus kinase inhibitors. Results In total, 191 patients were evaluated. The mean patient age was 44.5 years, and most were male (117 [61.3%]). Baseline characteristics were similar between radiographic and non-radiographic axSpA patients, with a higher proportion of patients in the radiographic group (116 [60.7%] vs. 75 [39.3%]). Significant improvements in disease severity were observed with SC IFX from treatment initiation to data collection (severe disease: 37.4% to 3.2%), along with significantly lower levels of pain and fatigue, and fewer tender entheseal points and affected joints (all p < 0.0001). SC IFX treatment was also associated with improvements in musculoskeletal, extra-articular, systemic, and functional symptoms, and inflammatory imaging features. Subgroup analysis showed that SC IFX was effective across various patient populations with differing characteristics such as age, prior experience with advanced therapies, or coexisting conditions. SC IFX showed high treatment satisfaction for both physicians and patients. No new safety signals were reported. Conclusions In this real-world study, SC IFX demonstrated clinical effectiveness in both radiographic and non-radiographic axSpA, with consistent results across diverse patient characteristics. Both physicians and patients reported high satisfaction with no new safety concerns. This analysis suggests that SC IFX can be an effective, convenient, and well-tolerated treatment option for diverse axSpA patient populations.