Summary Background Interleukin (IL)‐31 affects the inflammatory response, is involved in epidermal barrier disruption in atopic dermatitis (AD) and plays a key role in pruritus. Nemolizumab, a humanized monoclonal antibody against IL‐31 receptor A, reduced pruritus in patients with AD after a 16‐week administration period. Objectives To examine the long‐term effectiveness and safety of nemolizumab in patients aged ≥ 13 years with AD and inadequately controlled moderate‐to‐severe pruritus. Methods In two long‐term phase III studies, nemolizumab 60 mg every 4 weeks (Q4W) was administered subcutaneously, concomitantly with topical treatments. Study‐JP01 patients received double‐blind nemolizumab or placebo for 16 weeks, and then entered a 52‐week extension period in which all patients received nemolizumab (nemolizumab/nemolizumab and placebo/nemolizumab groups). Study‐JP02 patients received nemolizumab for 52 weeks. Both studies included an 8‐week follow‐up period. Results Study‐JP01 nemolizumab/nemolizumab and placebo/nemolizumab, and Study‐JP02 nemolizumab groups comprised 143, 72 and 88 patients, respectively. In the nemolizumab/nemolizumab group, there were clinically meaningful improvements from the start of treatment to week 68 in the pruritus visual analogue scale (66% decrease) and Eczema Area and Severity Index (78% decrease). Quality of life (QoL) indicators improved after the first nemolizumab dose; improvements were maintained during the follow‐up period. The long‐term safety profile was consistent with previous studies, with no unexpected late‐onset adverse events. Conclusions Nemolizumab 60 mg Q4W with concomitant topical treatments in patients with AD and inadequately controlled moderate‐to‐severe pruritus produced a continuous improvement in pruritus, signs of AD, and QoL for up to 68 weeks, with a favourable safety profile. What is already known about this topic? Pruritus, a characteristic symptom of atopic dermatitis (AD), causes distress to patients, reducing quality of life and affecting sleep and daily activities. Nemolizumab (plus topical agents) has previously been shown to reduce pruritus associated with AD to a greater extent than placebo over 16 weeks. As patients with AD suffer from repeated phases of relapse and remission, it is important to extend the periods of relief from pruritus and rash. What does this study add? Data from two long‐term (≥ 52 weeks) phase III studies confirmed that nemolizumab plus topical agents increased or maintained effectiveness through the study duration, with continuous improvement after week 16. Acute itchiness or flare of AD were rarely observed during the 8‐week follow‐up period. The results support the long‐term use of nemolizumab with concomitant topical agents in patients with AD and inadequately controlled moderate‐to‐severe pruritus. Linked Comment: S. Barbarot. Br J Dermatol 2022; 186:608. Plain language summary available online