Effect of filgotinib, a selective JAK 1 inhibitor, with and without methotrexate in patients with rheumatoid arthritis: patient-reported outcomes

Background: The aim was to assess patient-reported outcomes (PROs) in patients with rheumatoid arthritis (RA) treated with filgotinib during two phase 2b, 24-week, randomized, placebo-controlled studies. Methods: Patients with moderate-to-severe active RA and an inadequate response to methotrexate (MTX) were randomized to daily placebo or filgotinib 50 mg, 100 mg, or 200 mg as add-on therapy to MTX (NCT01888874) or as monotherapy (NCT01894516). At week 12, nonresponders receiving filgotinib 50 mg in both studies or placebo in the add-on study, and all patients receiving placebo as monotherapy, were re-assigned to filgotinib 100 mg. PROs were measured using the Health Assessment Questionnaire - Disability Index (HAQ-DI) including Patient Pain assessed by visual analog scale, and the Patient Global Assessment of Disease Activity (Patient Global), the Functional Assessment of Chronic Illness Therapy (FACIT)-Fatigue Scale (Version 4), and the 36-Item Short Form Health Survey (SF-36). Results: At week 12, improvements in all PROs, apart from the SF-36 mental component in the add-on study, were statistically better with filgotinib than placebo; some improvements were noted as early as the first assessment time point (week 1 or week 4). Filgotinib improved HAQ-DI by 0.58-0.84 points, FACIT-Fatigue by 6.9-11.4 points, Patient Global by 25.2-35.6 mm, and Pain by 24.2-37.9 mm; scores were maintained or improved to week 24. Across all PROs, more patients achieved minimal clinically important differences and normative values with filgotinib 200 mg than placebo. Patients re-assigned to filgotinib 100 mg at week 12 experienced improvements in PROs between weeks 12 to 24. Conclusions: Filgotinib as MTX add-on therapy or as monotherapy demonstrated rapid and sustained (to 24 weeks) improvements in health-related quality of life and functional status in patients with active RA.