In the U.S.A., an Investigator's Global Assessment ( IGA ) score of less than or equal to 1 ( clear or almost clear skin ) has been the standard measure in regulatory outcomes for registration clinical trials in atopic dermatitis, including those supporting the recent approval of Dupilumab ( Dupixent ).
The aim of the study was to evaluate the treatment effect of Dupilumab in patients with IGA more than 1 at the end of treatment, using other validated outcome measures for atopic dermatitis signs, symptoms and quality of life.
LIBERTY AD SOLO 1 and 2 were two 16-week, randomized, double-blind trials enrolling adult patients with moderate-to-severe atopic dermatitis ( IGA greater than or equal to 3 ) inadequately controlled with topical treatment.
Researchers have performed a post hoc analysis in patients receiving Dupilumab 300 mg every 2 weeks ( q2w ) or placebo.
Outcome measures in patients with IGA more than 1 included Eczema Area and Severity Index ( EASI ), pruritus numerical rating scale ( NRS ), affected body surface area ( BSA ), Patient-Oriented Eczema Measure ( POEM ) and Dermatology Life Quality Index ( DLQI ).
At week 16, 278 of 449 Dupilumab q2w-treated patients ( median age 36·0 years ) and 396 of 443 placebo-treated patients had IGA more than 1.
Among patients with IGA more than 1 at week 16, Dupilumab significantly improved several outcome measures compared with placebo: EASI ( -48·9% vs. -11·3%, P less than 0·001 ), pruritus NRS ( -35·2% vs. -9·1%, P less than 0·001 ), affected BSA ( -23·1% vs. -4·5%, P less than 0·001 ), POEM score greater than or equal to 4-point improvement ( 57·4% vs. 21·0%, P less than 0·001 ) and DLQI score greater than 4-point improvement ( 59·3% vs. 24·4%, P less than 0·001 ).
In conclusion, in patients with IGA more than 1 at week 16, Dupilumab has induced statistically significant benefits in multiple validated outcome measures compared with placebo.
The IGA less than or equal to 1 end point significantly underestimates clinically relevant Dupilumab treatment effects. ( Xagena )
Silverberg JI et al, Br J Dermatol 2019; Epub ahead of print