Topical isotretinoin eases symptoms in recessive congenital ichthyosis

A phase IIb trial has found that TMB-001, a novel topical isotretinoin ointment, can safely improve symptoms of hyperkeratosis and widespread scaling in patients with X-linked recessive or autosomal recessive congenital ichthyosis (CI).

Thirty-three patients participated in the study, of whom 11 were given TMB-001 at a 0.05% dose, while 10 were treated with a 0.1% dose; the remaining 12 patients were given vehicle as a control. Only those who were ≥9 years of age, had 10–90 percent of total body surface area involvement, and had Visual Index for Ichthyosis Severity (VIIS) score ≥3 for ≥2 assessment areas were eligible for enrollment.

The median time to a 50-percent or greater reduction in VIIS score was 28.0 and 54.0 days for the 0.05% and 0.1% doses of TMB-001, respectively, as compared with 63.5 days in the control group. The difference between the lower TMB-001 dose and vehicle was statistically significant (p=0.02).

Similarly, the 0.05% dose of TMB-001 led to significantly more frequent improvement of ≥2 grades in the Investigator Global Assessment (IGA) scale, as compared with vehicle control.

A significantly greater percentage of patients treated with 0.05% TMB-001 achieved both the VIIS and IGA endpoints vs vehicle. Of note, the 0.1% TMB-001 dose was only nominally better than vehicle.

“Interestingly, TMB-001 0.05% demonstrated improved efficacy vs 0.1%; additional characterization is needed to explain this finding,” the researchers said. “These results support ongoing TMB-001 efficacy and safety investigation as a promising alternative to oral retinoids for patients with CI.”