Characteristics and outcomes for participants with congenital ichthyosis who responded to treatment with the topical isotretinoin formulation TMB-001: results from the Phase IIb CONTROL study

Abstract

Background Emollients and keratolytics are frequently used to manage symptoms of congenital ichthyosis (CI). Systemic retinoid treatment is complicated by teratogenicity and dose-limiting adverse effects. Objectives This analysis from the randomized Phase IIb CONTROL study investigated the characteristics of participants who responded to treatment with TMB-001, a novel topical isotretinoin ointment formulation. Methods Participants≥9 years of age with genetically confirmed CI and≥2 (out of 4) Visual Index for Ichthyosis Severity (VIIS) assessment areas with≥3 scaling score were randomized 1: 1: 1 to TMB-001 0.05%, TMB-001 0.1% or vehicle, twice daily for 12 weeks. Efficacy endpoints included the proportion of participants with≥50% reduction in VIIS-scaling (VIIS-50) compared with baseline and≥2-grade reduction in Investigator’s Global Assessment (IGA)-scaling score compared with baseline. Changes in body surface area (BSA) involvement, Dermatology Life Quality Index (DLQI) scores and Itch-Numeric Rating Scale (I-NRS) scores were assessed. Results Among the 33 participants (11 randomized to TMB-001 0.05%, 10 to TMB-001 0.1% and 12 to vehicle), median age was 29 years (range 9–80), and most were male (64%) and White (79%). Baseline demographics were generally similar among participants who did or did not achieve TMB-001 treatment success. Participants who had lower mean BSA involvement and higher DLQI and I-NRS scores at baseline were more likely to achieve VIIS-50. Similarly, higher baseline DLQI and I-NRS scores were associated with IGA response; BSA involvement was similar for IGA responders vs. nonresponders. Conclusions Higher DLQI and I-NRS scores at baseline were associated with participants achieving treatment success by VIIS-50 and IGA response. Lower BSA involvement was associated with VIIS-50 success.