Laboratory Changes During Dupilumab Treatment for Atopic Dermatitis.

Introduction: Dupilumab is an IL-4/IL-13 inhibitor monoclonal antibody approved for the treatment of moderate-to-severe atopic dermatitis (AD) with remarkable safety and efficacy profiles. However, former studies have reported an increase in serum eosinophils during treatment, with undetermined clinical significance. The objective of this study is to evaluate changes in blood eosinophils and other laboratory parameters while on dupilumab.

Methods: We conducted a multicenter, prospective, observational study from 2018 to 2022 with adolescent and adult patients with moderate-to-severe atopic dermatitis treated with dupilumab from Hospital Universitario Virgen de las Nieves, Spain, and Coimbra University Hospital, Portugal. Clinical scoring of the dermatitis, complete blood count, total serum IgE and LDH levels were collected at baseline and on weeks 8, 16, 24 and 48.

Results: We included a total of 81 patients (41 women/40 men; mean age of 30.86±12.26 years). Clinical and demographic characteristics were similar across centres. AD severity scales (EASI, SCORAD, ItchVAS and SleepVAS) showed sustained improvement from week 8 of treatment onwards. Eosinophil levels were significantly higher on week 16 (0.69×10³/μL) vs baseline (0.41×10³/μL) (p=0.018) and returned to baseline levels on week 48 (0.59×10³/μL, p>0.05). LDH and IgE levels decreased during the study.

Conclusion: Our study showed a significant clinical improvement of AD but a mild and self-limited increase in eosinophil levels on week 16, not associated with any clinical signs. Therefore, elevated serum eosinophil levels in AD patients on dupilumab does not seem clinically relevant and should not condition treatment withdrawal.