Nemolizumab Improves Pruritus in Patients With Intrinsic Atopic Dermatitis Lacking Atopic Predisposition: A Single‐Centre Pilot Retrospective Cohort Study

ABSTRACT Interleukin (IL)‐31 is a key therapeutic target for severe pruritus in atopic dermatitis (AD). Nemolizumab, an IL‐31 receptor A antibody, has been available in Japan since 2022 for treating AD‐related pruritus. This retrospective study aimed to identify the characteristics of patients with AD for whom nemolizumab is appropriate and most effective, focusing on its efficacy in alleviating pruritus. We reviewed the clinical data of patients with AD who received 60 mg of nemolizumab between 2022 and 2024 at Fukuoka University Hospital. Patients who achieved a ≥ 4‐point improvement on the Peak Pruritus Numerical Rating Scale (PP‐NRS4) within 16 weeks were classified as responders. Background characteristics, including atopic predisposition and total serum immunoglobulin E (IgE) levels, were compared between responders and non‐responders. Multivariate analysis was performed to identify treatment response predictors. Sixteen (64%) of the 25 patients treated with nemolizumab achieved PP‐NRS4 within 16 weeks. Of the 25 patients, 14 had extrinsic AD with an atopic predisposition, although only 5 (36%) achieved PP‐NRS4. All 11 patients with intrinsic AD achieved PP‐NRS4 ( p = 0.001). The median total serum IgE level was significantly lower in responders (74.5 IU/mL) than in non‐responders (691.5 IU/mL, p = 0.0034). Multivariate analysis revealed that higher baseline IgE levels were associated with poorer PP‐NRS4 outcomes (standardised β = −0.63033, p = 0.0154). Serum total IgE levels, indicative of an atopic predisposition, are critical predictors of nemolizumab efficacy in alleviating pruritus. These findings underscore the importance of patient selection based on IgE levels for optimising nemolizumab therapy in AD.