Abstract: 【Abstract】 Objective To evaluate clinical efficacy and safety of dupilumab in the treatment of moderate and severe atopic dermatitis （AD） in the elderly. Methods An observational study was conducted, and a total of 42 elderly patients with moderate to severe AD were collected from Department of Dermatology, the First Affiliated Hospital of Soochow University from September 2021 to June 2022. These patients all received subcutaneous injection of dupilumab at an initial dose of 600 mg, followed by every-2-week injections at a dose of 300 mg, and the total course of treatment was 16 weeks. Clinical indicators, including eczema area and severity index （EASI）, numerical rating scale （NRS）, dermatology life quality index （DLQI） and investigator′s global assessment （IGA）, were recorded at weeks 0, 4, 8, 12 and 16, and the proportion of patients achieving more than 50% （EASI-50） and 75% （EASI-75） improvement in EASI scores were calculated; related laboratory indicators, including total serum immunoglobulin E （IgE） levels and eosinophil counts, were recorded at weeks 0, 4 and 16. During the treatment, adverse events were recorded. Statistical analysis was carried out by using chi-square test, one-way analysis of variance and t test with SPSS27 and GraphPad Prism 9.0 software. Results Among the 42 patients, there were 25 males （59.5%） and 17 females （40.5%）, and their age was 71.82 ± 16.81 years. Among them, 17 patients （40.5%） presented with generalized eczema phenotype, 15 （35.7%） with flexor eczema phenotype, and 10 （23.8%） with prurigo nodularis phenotype. At weeks 4 and 16 after start of the treatment, the mean EASI score significantly decreased by 38.4% and 73.3% respectively, the mean NRS score significantly decreased by 53.0% and 77.4% respectively, and the mean DLQI score significantly decreased by 58.2% and 93.8% respectively compared with the corresponding scores before the treatment （P < 0.05 or 0.001）. At weeks 4 and 16, the proportions of patients achieving an IGA score of 0 or 1 were 11.9% and 61.9% respectively, the proportions of patients achieving EASI-50 were 11.9% and 76.2% respectively, and the proportions of patients achieving EASI-75 were 2.4% and 57.1% respectively. Compared with the baseline levels, the mean total serum IgE level decreased by 23.1% and 38.2% at weeks 4 and 16 respectively （P = 0.274, 0.395, respectively）, and the mean eosinophil count decreased by 24.4% and 37.5% at weeks 4 and 16 respectively （P = 0.059, 0.735, respectively）. During the treatment, mild adverse events occurred in 6 （14.3%） patients, including conjunctivitis （3 cases）, fungal infection of the head and face （2 cases）, and psoriasiform dermatitis （1 case）, which subsided after symptomatic treatment. Conclusion Dupilumab exhibited a rapid onset and marked efficacy in the treatment of moderate and severe AD in the elderly, with few and mild adverse events; however, some patients had not achieved EASI-50 or EASI-75 after 16-week treatment, and maintenance treatment was required.

Key words: Dermatitis, atopic, Aged, Therapy, Biological agents, Dupilumab