Geographic Analysis of the Safety and Efficacy of Filgotinib in Rheumatoid Arthritis

Global clinical trials in rheumatoid arthritis (RA) often do not recruit enough patients from diverse racial and ethnic backgrounds to identify any potential differences in treatment outcome across such groups. To overcome this limitation, using data from five previous clinical trials and two ongoing trial extensions, this study aimed to assess the efficacy and safety of filgotinib in patients with RA across geographic regions. This was a post hoc, exploratory analysis of data from male and female patients with RA meeting the 2010 RA criteria as defined by the American College of Rheumatology (ACR) and European Alliance of Associations for Rheumatology. Data were analyzed from phase 2 (DARWIN 1–2) and phase 3 (FINCH 1–3) clinical trials, as well as two long-term extension studies (DARWIN 3, FINCH 4), of filgotinib. Efficacy endpoints included ACR 20 Clinical trials in rheumatoid arthritis recruit too few patients from diverse ethnic backgrounds to be able to identify differences in treatment outcomes. In adults with moderate-to-severe active rheumatoid arthritis who do not tolerate or have responded poorly to other advanced treatments, the Janus kinase inhibitor filgotinib can be used alone or in combination with the immunosuppressant methotrexate. Using data from 4695 patients with rheumatoid arthritis from five previous clinical trials and two ongoing trial extensions, this paper examined the efficacy and safety of filgotinib in patients with rheumatoid arthritis across geographic locations worldwide. Patients were grouped by region: North America, South and Central America, Western Europe, Eastern Europe, East Asia, South and Southeast Asia, and Other (South Africa, New Zealand, Australia, and Israel). The efficacy of filgotinib in treating the symptoms of rheumatoid arthritis was assessed using several measures of disease activity, with changes in patient quality of life determined using a health assessment questionnaire. Safety data were reported as the rates of side effects experienced by patients. Across different geographic regions, no major differences in filgotinib treatment response were observed. Rheumatoid arthritis disease activity levels were consistently lower in patients receiving filgotinib than in patients receiving placebo. Across the regions examined, quality-of-life scores also improved to a greater degree in patients receiving filgotinib compared with placebo. The rates of side effects, including infections, were similar irrespective of region. The number of deaths was low, mostly resulting from cardiovascular events, infections, and malignancies. This study demonstrates that the efficacy and safety of filgotinib are consistent in patients with rheumatoid arthritis from a broad range of geographic regions and ethnic backgrounds.