Efficacy and safety of filgotinib in patients with rheumatoid arthritis: week 156 interim results from a long-term extension study.

Background: Janus kinase inhibitors are an effective option for achieving sustained remission or low disease activity in patients with rheumatoid arthritis (RA) following inadequate response to conventional synthetic disease-modifying anti-rheumatic drugs. Filgotinib is a Janus kinase 1-preferential inhibitor available in two doses for moderate-to-severe RA. We report the long-term efficacy and safety of filgotinib.

Methods: In the ongoing long-term extension study FINCH 4 (NCT03025308), patients continue filgotinib 200 mg or 100 mg from FINCH 1, 2 or 3 or receive filgotinib 200 mg or 100 mg de novo. Efficacy assessments up to week 156 include American College of Rheumatology 20% response (ACR20), Disease Activity Score 28 using C-reactive protein of <2.6, Clinical Disease Activity Index of ≤2.8, Simplified Disease Activity Index of ≤3.3 and Boolean remission (1.0 and 2.0) with non-responder imputation.

Results: In patients with an inadequate response to methotrexate, 60.2% and 54.6% receiving de novo filgotinib 200 mg and 100 mg had an ACR20 at week 156, respectively, as did 67.3% and 59.5% of those who continued filgotinib 200 mg and 100 mg. At week 156, Boolean remission 1.0 was achieved by 18.8% and 15.4% of patients treated with de novo filgotinib 200 mg and 100 mg, respectively, and by 21.1% and 18.5% when Boolean 2.0 criteria were applied. Similar efficacy data were seen in patients from FINCH 2 and 3. Safety data were consistent with the known safety profile of filgotinib.

Conclusion: In FINCH 4, filgotinib 200 mg and 100 mg (continuous or de novo) demonstrated sustained efficacy up to week 156 in patients enrolled from FINCH 1, 2 or 3, with no unexpected safety results.