Identifying Week 48 Delayed Responders to Tralokinumab in Real-World Practice for Japanese Patients with Moderate-to-Severe Atopic Dermatitis

<u><b><i></i></b></u> <u><b><i>Background:</i></b></u> Some patients with atopic dermatitis (AD) show delayed response to anti-interleukin-13 antibody tralokinumab by 1 year. However, predictive factors for the delayed response are unknown.<u><b><i>Objective:</i></b></u> To clarify predictive factors for week 48 delayed responders to tralokinumab.<u><b><i>Methods:</i></b></u> We conducted a prospective study on 71 Japanese patients with moderate-to-severe AD who received tralokinumab at least for 48 weeks, from October 2023 to February 2025. We defined week 48 delayed responders as patients who achieved investigator's global assessment (IGA) 0/1 at week 48 but not at or before week 24, and defined week 48 poor responders as those who did not achieve IGA 0/1 through 48 weeks. We compared patients' background factors and baseline values of clinical and laboratory indexes between delayed responders versus poor responders.<u><b><i>Results:</i></b></u> Thirteen or 27 patients were defined as week 48 delayed responders or poor responders, respectively. Compared with poor responders, delayed responders had lower proportions of males and prior systemic therapy, and lower baseline values of thymus and activation-regulated chemokine (TARC) and lactate dehydrogenase (LDH).<u><b><i>Conclusions:</i></b></u> Female sex, absence of prior systemic therapy, and lower baseline values of TARC and LDH may predict the week 48 delayed responders to tralokinumab in patients with AD.