Early response to ivarmacitinib and its impact on long-term efficacy in patients with moderate-to-severe atopic dermatitis: a post hoc analysis of a phase-III trial

Background Ivarmacitinib, also known as SHR0302, is a novel highly selective Janus kinase 1 inhibitor that suppresses cytokine signaling pathways involved in the pathogenesis of atopic dermatitis (AD).Objective We aimed to explore the early response to ivarmacitinib in patients with moderate-to-severe AD and its impact on long-term efficacy.Methods This post hoc analysis included all patients receiving ivarmacitinib in the phase-III trial (NCT04875169). Patients were divided into early and nonearly responders, depending on whether they achieved an Eczema Area and Severity Index (EASI) 75 response at week (W) 4.Results Among the 225 patients included, 83 (36.9%) were classified as early responders and 142 (63.1%) as nonearly responders. The EASI 75 (81.9% vs. 47.2%, p < 0.001) and Investigator’s Global Assessment (IGA) (56.6% vs. 28.9%, p < 0.001) response rates at W16 were higher in early responders. Additionally, early responders had higher EASI 90, EASI 100, and Scoring Atopic Dermatitis 75 and 90 response rates throughout W8 to W52. The changes in Dermatology Life Quality Index and Patient-Oriented Eczema Measure scores from baseline were greater in early responders from W8 to W52.Conclusion Early response to ivarmacitinib at W4 yields better long-term efficacy in patients with moderate-to-severe AD.