According to a post hoc analysis of Phase 3 studies, the combination of once-daily filgotinib (FIL) 200 or 100 mg with methotrexate (MTX) or with conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) offered sustained and prompt improvements in quality of life, disease activity, work productivity loss, fatigue, functional impairment, and presenteeism in rheumatoid arthritis people who were MTX-naïve or who had unsatisfactory response to MTX or biological DMARDs (bDMARDs).

Investigators undertook this study to explore filgotinib's effect on measures of patient-reported outcomes and health-related quality of life (HRQL) in people suffering from rheumatoid arthritis.

MTX-naïve subjects were given 200 or 100 mg filgotinib + MTX (FIL200+MTX, FIL100+MTX), 200 mg filgotinib monotherapy (FIL200) or MTX monotherapy through fifty-two weeks.

Those subjects having inadequate response to MTX (MTX-IR) were given FIL200+MTX, FIL100+MTX, 40 mg adalimumab +MTX (ADA+MTX), or placebo + MTX (rerandomized to FIL200+MTX or FIL100+MTX at week twenty-four) through fifty-two weeks. Subjects having inadequate response to bDMARD (bDMARD-IR) were given FIL200 or FIL100 or placebo with background stable csDMARDs for up to twenty-four weeks.

The patient-reported outcomes evaluated during the trials, included: (i) Patient Global Assessment of Disease Activity (PtGA), (ii) Medical Outcomes Study 36-Item Short Form Survey (SF-36), (iii) Health Assessment Questionnaire-Disability Index (HAQ-DI), (iv) Work Productivity and Activity Impairment Questionnaire-Rheumatoid Arthritis (WPAI-RA), (v) Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-Fatigue), and (vi) physical/mental component summary (PCS/MCS).

Reporting of data was done in terms of least-squares mean alterations from the baseline. All the statistical comparisons were of filgotinib groups vs their control groups.

In MTX-naïve subjects, alteration from the baseline (standard deviation) in HAQ-DI was reported to be − 1.00 (0.03) with FIL200+MTX, − 0.94 (0.04) with FIL100+MTX, and − 0.91 (0.04) with FIL200 alone vs. − 0.81 (0.03) with MTX alone at week twenty-four. In MTX-IR subjects, alteration from the baseline in HAQ-DI was − 0.69 (0.04) with FIL200+MTX, − 0.57 (0.04) with FIL100+MTX, and − 0.60 (0.04) with ADA vs − 0.40 (0.04) with placebo+MTX at week twelve.

In bDMARD-IR subjects, alteration from the baseline in HAQ-DI was − 0.50 (0.06) with FIL200+csDMARD and − 0.46 (0.05) with FIL100+csDMARD vs − 0.19 (0.06) with placebo+csDMARD at week twelve. Alteration in PtGA, WPAI, SF-36 PCS and MCS, FACIT-Fatigue was noted to favor filgotinib therapy over ADA, MTX, and placebo. A higher percentage of participants reported substantial differences with filgotinib plus csDMARDs (including MTX) and with FIL200 monotherapy when compared to the comparators.

Hence, filgotinib (Janus kinase 1 inhibitor) improved the patient-reported outcomes across the patient populations. It appears to be an efficacious therapeutic choice for people having an unsatisfactory response to bDMARDs or MTX and for MTX-naïve people.