Stapokibart/CM310, a humanized monoclonal antibody targeting the interleukin-4 receptor α chain, has shown promising treatment benefits in patients with moderate-to-severe atopic dermatitis in previous phase II clinical trials. We aimed to evaluate the long-term efficacy and safety of stapokibart in adults with moderate-to-severe atopic dermatitis. Enrolled patients who previously completed parent trials of stapokibart received a subcutaneous stapokibart 600-mg loading dose, then 300mg every 2weeks up to 52weeks. Efficacy outcomes included the proportions of patients with ≥50%/75%/90% improvements from baseline of parent trials in the Eczema Area and Severity Index, Investigator's Global Assessment, and weekly average of the daily Peak Pruritus Numerical Rating Scale. In total, 127 patients were enrolled, and 110 (86.6%) completed the study. At week52, the Eczema Area and Severity Index-50/75/90 response rates were 96.3%, 87.9%, and 71.0%, respectively. An Investigator's Global Assessment 0/1 with a ≥2-point reduction was achieved in 39.3% of patients at week16, increasing to 58.9% at week52. The proportions of patients with ≥3-point and ≥4-point reductions in the weekly average of daily Peak Pruritus Numerical Rating Scale scores were 80.2% and 62.2%, respectively, at week52. Improvement in patients' quality of life was sustained over a 52-week treatment period. Treatment-emergent adverse events occurred in 88.2% of patients, with an exposure-adjusted event rate of 299.2 events/100 patient-years. Coronavirus disease 2019, upper respiratory tract infection, and conjunctivitis were the most common treatment-emergent adverse events. Long-term treatment with stapokibart for 52weeks showed high efficacy and good safety profiles, supporting its use as a continuous long-term treatment option for atopic dermatitis. ClinicalTrials.gov identifier: NCT04893707 (15 May, 2021).