Clinical pharmacology of filgotinib in the treatment of rheumatoid arthritis: current insights

Introduction: Rheumatoid arthritis (RA) is a chronic autoimmune disease, whose natural course has been deeply modified thanks to the development of new therapeutic approaches. The Janus kinase inhibitors (Jakinibs) represent the newest class of drugs introduced for treating RA. Among these, Filgotinib (FIL) has been developed as Janus kinase1 (JAK1) selective inhibitor, specifically targeting key pro-inflammatory mediators in RA pathogenesis. Areas covered: This narrative review provides an overview on FIL as new therapeutic approach for RA, with focus on its pharmacological properties, clinical efficacy, and safety profile. The following electronic databases were adopted for the study search: PubMed, Google Scholar, ClinicalTrials.gov and Abstract archive from the American College of Rheumatology and the European Alliance of Associations for Rheumatology. Expert opinion: The phase II and phase III randomized controlled trials (RCTs) performed so far and their long-term extensions showed a comparable clinical efficacy of FIL to biologic treatments, with an acceptable safety profile. Thanks to these data, FIL was approved in Europe and Japan for the treatment of active RA, increasing the spectrum of therapeutic approaches and improving the possibility of a more tailored therapeutic strategy. Real-life data and head-to-head clinical trials will be needed to confirm its efficacy and safety.