Arthritis Rheumatol: The efficacy and safety of the new JAK3/TEC inhibitor PF-06651600 (ritlecitinib) for moderate to severe rheumatoid arthritis

The 2a-phase, eight-week double-blind parallel group study assessed the efficacy and safety of PF-06651600 (ritlecitinib) in patients with rheumatoid arthritis (RA), a nonverse inhibitor in the family of ritlecitinib, Janus kinase 3 (JAK3) and tyrosine kinase (TEC) kinase expressed in liver cancerrandomly assigned 70 patients with anti-gualine protein antibodies and/or rheumatism factor serologically positive at 3:2, oral PF-06651600 (200 mg, 1 time per day ( QD) or placebo treatment for 8 weeksPatients were poorly reacted to methotrexate, and up to 50% of patients had previously been treated with a tumor necrosis inhibitorThe primary endpoint was a change in the 8-week Simplified Disease Activity Index (SDAI) score relative to the baseline, which was evaluated by Bayesian analysis of the informative prior distribution of the placebo responsethe average change in the SDAI score relative to the baseline in the 8th week of PF-06651600 group (-26.1 (-29.7, -22.4)) compared to the placebo group (-16.8,-95% -20.9, -12.7) ;PMost adverse events (AEs) are mild in severity and no treatment is reported to be severely or severely AEs, or deathThe most common AEs are infections as well as skin and subcutaneous tissue diseasesIn the PF-06651600 group, there was one case of mild herpes simplex epes that was thought to be related to treatment, but was relieved within 3 days and there was no discontinuation or antiviral treatmentin this small eight-week study, oral JAK3/TEC inhibitor PF-06651600 (200mg QD) was associated with significant improvements in RA disease activity and good tolerance