Efficacy and safety of filgotinib in methotrexate-naive patients with rheumatoid arthritis with poor prognostic factors: post hoc analysis of FINCH 3

Objective This analysis evaluated efficacy and safety of filgotinib, a Janus-associated kinase 1-preferential inhibitor, in methotrexate (MTX)-naive patients with rheumatoid arthritis (RA) with multiple poor prognostic factors (PPFs). Methods This was a post hoc analysis of the phase III, randomised, double-blind, active-controlled, FINCH 3 study (clinicaltrials.gov NCT02886728). Patients received once-daily oral filgotinib 200 or 100 mg plus once-weekly oral MTX ≤20 mg (FIL200 + MTX and FIL100 + MTX), filgotinib 200 mg monotherapy (FIL200), or oral MTX monotherapy (MTX-mono) for up to 52 weeks. PPFs investigated were seropositivity for rheumatoid factor or anticyclic citrullinated peptide antibodies, high-sensitivity C reactive protein (CRP) ≥4 mg/L, Disease Activity Score in 28 joints with CRP (DAS28(CRP)) >5.1, and presence of erosions. Filgotinib efficacy and safety in patients with all four PPFs at baseline were explored versus MTX-mono within this subgroup and compared informally with the overall population. Results Of 1249 patients in FINCH 3, 510 (40.8%) had all PPFs. Efficacy of FIL200 + MTX among these patients was comparable to the overall population, with higher rates of 20%/50%/70% improvement from baseline by American College of Rheumatology criteria, DAS28(CRP) <2.6, and remission; greater improvement in physical function and pain; and better inhibition of structural damage relative to MTX-mono. FIL100 + MTX and FIL200 were not consistently more efficacious versus MTX-mono. Safety of filgotinib in patients with PPFs was comparable to the overall population; no new safety signals were observed. Conclusion FIL200 + MTX efficacy and safety in patients with multiple PPFs were similar to the overall population.