Dupilumab Improves Atopic Dermatitis in Both Dark and Light Skin

Dupilumab treatment was significantly more effective improving the eczema area and severity index (EASI) among dark skin types (DST) than light skin types (LST), suggesting the possibility that dupilumab effectiveness may vary with skin type among patients with atopic dermatitis (AD). These study results were published in Journal of The American Academy of Dermatology International.

Researchers conducted an observational longitudinal cohort study using real-world data pooled from the UK-Irish A-STAR and the Dutch TREAT NL registries. Children and adults with AD were enrolled in the study at 13 centers in the UK from October 2018 to April 2021, and patients at 2 centers in the Netherlands were enrolled from November 2017 to June 2020. The study participants were evaluated during visits at baseline, 4 weeks, and additionally every 3 months.

Among a total of 235 patients, researchers noted skin types for 11 patients were missing and excluded from analyses comparing skin types, leaving Fitzpatrick skin types 1 to 3 (LST, n=156; 94.2% White) and Fitzpatrick skin types 4 to 6 (DST, n=68; Black, 25.0%; South Asian, 26.5%; Hispanic, 0.0%; White, 5.9%; other Asian [including those from Korea and China north of the Huai River] 17.7%; and mixed ethnicities, 22.0%).

Participants with DST vs LST more often had follicular eczema (22.1% vs 2.6%; P <.001), less allergic contact dermatitis (30.9% vs 47.4%; P =.03), higher baseline EASI scores (20.1 vs 14.9; P =.009), less previous phototherapy use (39.7% vs 59.0%; P =.008), and were younger (19.5 vs 29.0 years; P <.001). They found no differences between skin types for any other morphological features.

Overall, 168 patients (71.5%) were treated with dupilumab (DST, n=42; LST, n=121), 65 patients (27.7%) were treated with methotrexate (DST, n=22; LST, n=37), and 26 patients (11.1%) were treated with ciclosporin (DST, n=7; LST, n=19). The researchers noted 51 patients used conventional systemic therapy concomitantly with dupilumab (n=31), methotrexate (n=13), and ciclosporin (n=7). There were no significant differences for concomitant systemic therapy usage or mean usage duration between DST and LST.

There was a greater mean EASI reduction between baseline and 6 months with dupilumab when comparing DST vs LST and correcting for covariates (16.7 vs 9.7; adjusted P =.032). There were no differences for adverse events for any treatments (P >.05).

Dupilumab and methotrexate showed a significant P-value for skin type as interaction term for EASI (P <0.001 and P =0.04, respectively), which suggested that over time the course of EASI differs between DST and LST groups. Significant improvements were shown for all outcome measures in all skin types treated with dupilumab. The researchers also found significant improvement in all outcome measures treated with methotrexate and ciclosporin among LST, and among DST significant improvement in EASI for methotrexate were noted.

Limitations of the study include a lack of randomization, the unblinded observational study design, underpowered sample size, and the inclusion of patients on combined systemic therapies.

Researchers conclude, “[W]e found significant differences between AD patients with DST and LST, such as more severe disease at baseline and more follicular eczema in DST. Importantly, skin type may also influence treatment effectiveness of dupilumab in AD, as DST showed significantly greater EASI improvement than LST.”

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.