Evaluating filgotinib for the treatment of rheumatoid arthritis.

Filgotinib is an oral targeted synthetic disease-modifying antirheumatic drug (DMARD) that specifically inhibits JAKi. Filgotinib monotherapy, or a combination regimen with conventional synthetic (cs) DMARDs, has demonstrated efficacy in decreasing disease activity, with a well-managed safety profile in patients with early RA naive to DMARDs, and in RA that does not adequately respond to csDMARDs and/or biologic DMARDs. The selective inhibition of JAK1 may confer an improved safety profile, but further study is required as a potential testicular toxicity has been suggested. Filgotinib offers several advantages: oral administration, rapidity of action, efficacy as monotherapy, and demonstrated activity in difficult to treat RA. However, the placement of filgotinib in the therapeutic arsenal for RA may be influenced by the ongoing collection of long-term safety data from JAKi as a class.