In two 4-week exploratory Phase 2a trials in MTX-inadequate responder (IR) patients with RA, the highly selective JAK1 inhibitor filgotinib met the primary endpoint of ACR20 at Week 4, showing greater response than placebo.Study 1, a proof-of-concept study, included 127 patients randomised to placebo, filgotinib 100 mg BID or filgotinib 200 mg QD. Study 2, was a dose-ranging study and included 91 patients randomised to placebo, filgotinib 30 mg QD, filgotinib 75 mg QD, filgotinib 150 mg QD or fi...