Atopic Dermatitis Treatment Equally Effective in Extrinsic, Intrinsic Subtypes

Among 360 patients living with atopic dermatitis (AD) who had either intrinsic AD (13.6%) or extrinsic AD (86.4%), dupilumab (Dupixent) was equally effective regardless of immunoglobulin E (IgE) levels, according to study findings appearing in Journal of Clinical Medicine.

EAD is the more common of the 2 AD types, and it frequently has elevated serum IgE levels and is associated with other atopic conditions. With IAD, however, IgE levels typically remain normal and there is a lack of atopy. The Dermatology Clinic of the Turin University Hospital, in Italy, administered dupilumab to treat all of the patients in this retrospective observational study (adults, 18 years and older; adolescents, 12-17 years) for moderate to severe AD between January 2019 and March 2022.

Eczema Area and Severity Index (EASI) score had to be 24 or higher for the adult population, and the adolescent population had to have an EASI score of 24 or higher or localization in sensitive or visible areas, a numerical rating scale peak of pruritus of at least 7, or a Children’s Dermatology Life Quality Index (DLQI) score of 10 or higher.

“In the literature, very few studies have evaluated the efficacy of dupilumab by stratifying patients according to normal versus increased IgE values, following a ‘one-size-fits-all’ treatment approach,” investigators wrote. “With this study, we want to enrich the literature by comparing the efficacy of dupilumab in patients with IAD vs EAD in a real-life setting.”

Following baseline evaluation, treatment effectiveness was measured at 13, 32, and 48 weeks after dupilumab initiation. The treatment course for adults was a starting dose of 600 mg followed by 300 mg every other week. Adolescents received a starting dose of 400 mg at baseline followed by 200 mg every other week if weight was less than 60 kg, or the adult dosage if weight was 60 kg or greater.

Overall, more female than male patients had IAD (52% vs 49%) and more male patients had EAD (57% vs 43%). At baseline, mean (SD) EASI was lower in the IAD cohort compared with the EAD cohort, at 18.2 (11.97) vs 24.04 (10.34) (P < .01), and IgE levels were higher in the EAD group, at 3949.74 (5208.77) vs 70.64 (60.05) (P < .001). Significant differences were not seen for DLQI or the Patient-Oriented Eczema Measure.

For the 3 follow-up measures, the following EASI results were seen for the IAD and EAD groups, respectively:

• 13 weeks: 2.78 (5.62) vs 3.88 (5.13) (P = .028)
• 32 weeks: 1.79 (2.97) vs 2.96 (3.78) (P = .011)
• 48 weeks: 1.61 (1.60) vs 2.75 (4.04) (P = .222)

Both EASI75 and EASI90 did not differ significantly at any of the time points.

Analyses for head and neck EASI (H&N EASI), pruritis-related itching, and sleep disturbance outcomes following dupilumab treatment in both cohorts produced the following improved score changes from the first to the final follow-up:

• H&N EASI:
  • IAD: 0.54 (0.99) to 0.38 (0.62)
  • EAD: 0.98 (1.28) to 0.73 (1.02)
• Itch scores:
  • IAD: 2.74 (2.58) to 2.54 (2.10)
    • EAD: 3.02 (3.02) to 2.66 (2.33)
• Sleep disturbance:
  • IAD: 1.06 (2.03) to 0.75 (2.15)
  • EAD: 1.15 (2.2) to 0.55 (1.68)

Both DLQI score improvements and percentage of patients achieving a DLQI of 1/0 were equivalent at all follow-ups. Further, although mean IgE levels were higher in the EAD vs IAD groups overall—and mean absolute values for the EAD group declared statistically higher—totals did decrease in both groups at all timepoints.

“This study confirms that dupilumab appears to be equally as effective in the 2 study populations, regardless of IgE levels,” the study authors concluded. “It can also be seen that the efficacy of dupilumab is not closely related to the reduction in IgE values.”

They recommend larger prospective studies to confirm dupilumab’s effectiveness in IAD vs EAD, citing the present study’s retrospective nature as a major limitation on their findings’ wider applicability.

Reference

Gelato F, Mastorino L, Stepkina E, et al. Is dupilumab as effective in intrinsic atopic dermatitis as it is in extrinsic atopic dermatitis? J Clin Med. Published online March 11, 2023. doi:10.3390/jcm12062189