P081 A highly selective Janus kinase 1 inhibitor, ivarmacitinib ointment, for the treatment of atopic dermatitis: results from a phase II study

Abstract Atopic dermatitis (AD) is a pruritic chronic inflammatory skin disorder. Ivarmacitinib, a highly selective inhibitor of Janus kinase 1, potently suppresses cytokine signalling involved in AD pathogenesis. A randomized, double-blind, vehicle-controlled, seamless and adaptive-designed phase II/III study was conducted to evaluate the efficacy and safety of ivarmacitinib ointment in patients with AD. The results of phase II are reported here. The study was registered with ClinicalTrials.gov (NCT04717310). In total, 128 patients aged 18–65 years with mild-to-moderate AD were randomly assigned (1 : 1 : 1 : 1) to receive twice-daily topical ivarmacitinib ointment 2%, 1% or 0.5%, or vehicle for 8 weeks. Efficacy evaluation included Eczema Area and Severity Index (EASI), Investigator’s Global Assessment (IGA), Scoring of Atopic Dermatitis (SCORAD), Pruritus numerical rating scale (NRS) and Dermatology Life Quality Index (DLQI). At week 8, all three doses met the primary endpoint, mean percentage change of EASI from baseline. The results in the arms with ivarmacitinib 2%, 1% and 0.5% were −56.1%, −54.6% and −66.9% (P = 0.06, 0.08, 0.002, respectively), compared with vehicle (−40.2%). The ivarmacitinib 0.5% ointment group also achieved IGA response (IGA score of 0/1 with ≥ 2 points improvement from baseline) compared with vehicle. Other endpoints including SCORAD, NRS and DLQI all showed therapeutic benefit at week 8 in the ivarmacitinib ointment regimens. The ivarmacitinib ointment demonstrated good safety results and was well tolerated. In conclusion, ivarmacitinib ointment at 2%, 1% or 0.5% strength significantly improved signs and symptoms compared with vehicle and was well tolerated in adult patients with mild-to-moderate AD. This study was funded by Reistone Biopharma Co., Ltd.