A Double-Blind, Randomized, Vehicle-Controlled Phase 2 Study to Assess the Efficacy and Safety of GX-03 in Adult Subjects With Moderate to Severe Atopic Dermatitis (Eczema)

This Phase 2 study is designed to evaluate the efficacy and safety of GX-03, a topical petrolatum-based ointment containing polyhexanide (PHMB), in adult subjects with moderate to severe atopic dermatitis.

The study plans to enroll up to 120 eligible patients with a target of at least 100 completing the study and an ability to expand enrollment up to 200 subjects based on a pre-specified interim assessment conducted by an Independent Data Monitoring Committee (IDMC). Eligible subjects will be randomized in a double-blind manner to receive either GX-03 or matching vehicle control in a 1:1 allocation ratio. Study treatment will be self-administered topically to affected areas at least twice daily for 8 consecutive weeks.

Subjects will undergo efficacy evaluations at Baseline, Week 4, and Week 8 using validated atopic dermatitis assessment tools including vIGA-AD™, EASI, PP-NRS, and POEM. Safety assessments will include adverse event monitoring, concomitant medication review, and weekly safety check-ins.

The study incorporates an adaptive design with a single unblinded interim assessment performed by an independent IDMC after approximately 50 evaluable subjects have completed the Week 8 assessment or withdrawn prematurely. The interim analysis will evaluate conditional power for the primary endpoint and may result in continuation without modification, expansion of enrollment up to 200 total subjects, or curtailment of enrollment according to pre-specified criteria.

Statistical Analysis:

The primary efficacy analysis will compare treatment groups using a one-sided superiority hypothesis with a significance level of 0.025. Multiplicity across endpoints will be controlled using a hierarchical stepdown testing procedure. Safety analyses will be performed using two-sided statistical testing.

The Full Analysis Set (FAS) will serve as the primary efficacy population and includes randomized subjects who received at least one dose of study treatment and completed the Week 8 post-baseline EASI assessment.

Interim Analysis A single unblinded interim assessment will be conducted by an Independent Data Monitoring Committee after approximately 50 subjects complete the Week 8 visit or withdraw prematurely. The interim assessment will evaluate conditional power for the primary endpoint and may support continuation as planned, enrollment expansion up to 200 subjects, or curtailment of enrollment based on pre-specified IDMC criteria.

Safety Monitoring Safety evaluations include treatment-emergent adverse events, serious adverse events, concomitant medications, and weekly safety monitoring throughout the study duration.

Participants must meet all of the following criteria:

• Adults aged 18 to 80 years, inclusive
• Male or female subjects in good general health as determined by medical history
• Presence of visible eczematous skin with disease severity consistent with moderate to severe eczema, as assessed by:
• Eczema Area and Severity Index (EASI) or Validated Investigator Global Assessment for Atopic Dermatitis (vIGA-AD™)
• Ability to read, understand, and provide written informed consent in English
• Willingness and ability to comply with study procedures, including study visits and daily topical application
• Agreement to use only the assigned study product on designated areas of interest for the duration of the study

Exclusion criteria

Individuals meeting any of the following criteria will be excluded:

• Pregnant, breastfeeding, or planning pregnancy during the study
• Presence of any skin condition or dermatologic disease that could interfere with study treatment or assessments
• Use of systemic or topical immunosuppressive therapies, including corticosteroids, within 3 weeks prior to enrollment
• Use of anti-inflammatory medications (e.g., topical steroids, ibuprofen, celecoxib); steroid nasal or ophthalmic drops are permitted
• Use of topical medications at the test sites within 72 hours prior to enrollment
• Damaged or altered skin at or near test sites (e.g., sunburn, tattoos, scars, uneven pigmentation) that could confound evaluations
• Any medical condition that, in the investigator's judgment, places the subject at undue risk or compromises study integrity