Discontinuation Reasons and Drug Survival of Dupilumab in Real‐World Adult Atopic Dermatitis Patients in Three Healthcare Facilities in Tokyo and Yokohama (2018–2023)

ABSTRACT Dupilumab, a fully human IgG4 monoclonal antibody that inhibits interleukin (IL)‐4 and IL‐13 signaling by blocking the shared IL‐4α subunit, is the first targeted systemic therapy for moderate‐to‐severe atopic dermatitis (AD). The drug was introduced in Japan in April 2018, along with other countries around the same time, leading to a dramatic improvement in patients' quality of life. This study aims to provide practical insights into the real‐world use of dupilumab to support decision‐making in drug selection and patient education. We retrospectively analyzed the clinical course of 314 AD patients who commenced the treatment in a university hospital and two clinics in Tokyo and Yokohama, both in the greater Tokyo metropolitan area, from the launch of the drug until December 2022. Of the 314 patients, 180 (57.3%) remained on the treatment until June 2023, whereas 134 (42.7%) discontinued. Discontinuation reasons included: (i) negative outcomes, such as lack of efficacy or adverse effects, in 46 patients (14.6%) with a median treatment duration of 224 days; (ii) disease remission in 53 patients (16.9%); and (iii) non‐disease‐related or unknown reasons in 35 patients (11.1%). The drug survival rates at 1, 2, 3, and 4 years after initiation were 72.2%, 56.9%, 49.8%, and 42.3%, respectively. However, when considering only discontinuations due to negative outcomes, these increased to 89.3%, 82.7%, 78.8%, and 75.6%, respectively. To summarize, the drug survival rate in this group was significantly lower than those reported in Western countries. However, when discontinuations due to negative outcomes were considered separately, the rates were comparable. These findings highlight the excellent efficacy of dupilumab, while also suggesting that the doctors and patients in this region may be more inclined to discontinue the treatment despite its success compared with their Western counterparts.