Novel JAK1 inhibitor for patients with atopic dermatitis

Ivarmacitinib improved signs and symptoms in Chinese patients with moderate-to-severe atopic dermatitis (AD) in the phase 3 QUARTZ3 trial. The drug was well tolerated, supporting that this novel JAK1 inhibitor may be a treatment option for patients with AD.

“The JAK1 inhibitor ivarmacitinib is currently under clinical development for the treatment of AD, rheumatoid arthritis, ankylosing spondylitis, ulcerative colitis, Crohn’s disease, and alopecia areata,” said Prof. Jianzhong Zhang (Peking University People’s Hospital, China). He shared the results of the phase 3 QUARTZ3 trial (NCT04875169), which randomised 256 Chinese patients with moderate-to-severe AD 1:1:1 to either 4 or 8 mg daily of the JAK1 inhibitor ivarmacitinib or a placebo [1]. The co-primary endpoints of the study were an Investigator's Global Assessment (IGA) score of 0 or 1 (i.e. clear/almost clear skin) with more than 2 points improvement on this scale, and an Eczema Area and Severity Index (EASI)75 response.

After 16 weeks of therapy, 48.2% of the participants in the 8 mg arm, 42.5% of the participants in the 4 mg arm, and 8.3% of the participants in the placebo arm achieved the first primary endpoint, with ivarmacitinib being significantly more efficacious than placebo (P<0.001 for both). Similarly, an EASI75 response was reached in 71.8%, 60.9%, and 22.6% of the participants in the 8 mg arm, 4 mg arm, and placebo arm, respectively (P<0.001 for both active arms). Notably, the ivarmacitinib arms already obtained a significantly higher efficacy than the placebo after 4 weeks of treatment.

Prof. Zhang mentioned that both ivarmacitinib doses were well tolerated and that no increase in serious adverse events was observed in the active arms, as compared with the placebo arm. The most common adverse events in the 8 mg arm were upper respiratory infections (14.1%), increased blood creatine phosphokinase (11.8%), proteinuria (9.4%), folliculitis (9.4%), and hyperlipidaemia (9.4%).

“The results of this study indicate that ivarmacitinib may be a potential therapy for patients with moderate-to-severe AD,” concluded Prof. Zhang.

1. Zhang J, et al. Ivarmacitinib, a highly selective JAK1 inhibitor for moderate-to-severe atopic dermatitis (AD): 16-week results in Chinese population from a Phase 3 pivotal study. Late-breaker Session 5, WCD 2023, 3–8 July, Singapore, Singapore.