The purpose of this study is to investigate the efficacy and safety of two concentrations of topically applied ointment formulation of isotretinoin called TMB-001 (0.05% and 0.1% isotretinoin) in subjects 9 years of age and older for the treatment of congenital ichthyosis (CI), including recessive X-linked ichthyosis (RXLI) and autosomal recessive congenital ichthyosis-lamellar ichthyosis (ARCI-LI) subtypes.

Funding Source FDA-OOPD

This is a randomized, parallel, double-blind, vehicle-controlled study to evaluate the safety and efficacy of two concentrations of topical TMB-001 for the treatment of CI in subjects with either the ARCI-LI or RXLI subtypes. The duration of treatment will be 12 weeks. Each subject will participate in the study for up to 24 weeks (including up to a 90-day Screening period). Eleven study centers from United States of America and Australia participated in this global study. Each subject participated in the study for up to 24 weeks (including up to a 90-day Screening period).

Eligible subjects were randomized (1:1:1) to one of 3 treatment groups:

1. TMB-001, 0.05%, twice daily (bid)
2. TMB-001, 0.1%, bid
3. Vehicle Ointment (Control), 0%, bid

Subjects were evaluated on a monthly basis for safety and efficacy results over the 12- week treatment period. Efficacy was determined in 2 ways:

1. VIIS (or Visual Index of Ichthyosis Severity) "treatment success" (VIIS-50) was defined as ≥ 50% reduction from Baseline for VIIS scaling score for the sum of the scores for 'VIIS body areas' that had a Baseline score ≥ 3). The proportion of subjects achieving VIIS-50 at Visit 6 at Week 12 relative to Baseline was the primary efficacy endpoint and time point used to compare the two active treatments to vehicle.
2. The proportion of subjects achieving IGA (Investigator Global Assessment) treatment success will be the key secondary endpoint. For this endpoint, the IGA score was established as "treatment success" or "treatment failure" where "treatment success" is defined as at least a 2-grade decrease in severity score (for example, severe or score of 4 at baseline to mild or score of 2 at Visit 6) relative to Baseline at Visit 6 at week 12.

The safety analyses conducted were extent of exposure, changes in physical examinations and vital signs, blood and urine testing including urine pregnancy testing as indicated, local skin reactions (including burning/stinging, redness, erosions, and swelling) and other adverse events.

Inclusion Criteria:

• Subject is male or female, 9 years of age or older at Visit 2 (Baseline)
• Subject has provided written informed consent
• Females of child bearing potential must be surgically sterile or agree to 2 forms of birth control
• Subject has clinical diagnosis of Congenital Ichthyosis with genetic confirmation of subtype
• Subject has between 10% and 90% total BSA affected by Congenital Ichthyosis
• Subject has at least 2 VIIS assessment areas with a scaling score of 3 or greater

Exclusion Criteria:

• Subject has inflammatory skin diseases unrelated to ichthyosis
• Subject has used other prohibited topical treatments in the assessment areas within certain days from baseline
• Subject has used systemic retinoids within12 weeks of baseline
• Subject has untreated secondary infections
• Subject has lesions suspicious for skin cancer or untreated skin cancers

Double-blind