GX-03 Phase 2 Program Expands to Full Atopic Dermatitis Spectrum

Turn Therapeutics announced it has completed a comprehensive interim analysis of its adaptive phase 2 trial evaluating GX-03, an investigational non-systemic topical therapy, for atopic dermatitis (AD). The review identified clinically meaningful efficacy across a broader range of disease severity than initially anticipated, prompting expansion of the ongoing program to enroll patients across the full baseline Eczema Area and Severity Index (EASI) spectrum. The final stage 2 design will use the Hochberg multiple testing procedure to evaluate 4 efficacy endpoints rather than a single primary end point.¹

Stage 1 enrolled patients with moderate to severe AD by Investigator's Global Assessment (IGA), but baseline EASI scores spanned a wide range of total inflammatory burden. Efficacy observed in patients with EASI scores of 1.1 to 7.0, a range generally reflecting mild to moderate disease, extends the potential treatment opportunity for GX-03 into a population commonly managed with topical therapy. The finding informed the company's decision to combine all severity strata into a single, unified stage 2 efficacy population rather than restrict enrollment to more severe patients.¹

"A patient with extremely severe hand eczema, in both hands, might have to wear gloves just to eat or cook, and that patient might be an EASI 3 or 4. I would not want to tell that patient they have mild eczema according to the EASI scale when they have clinically severe hand eczema,” Bradley Burnam, chief executive officer of Turn Therapeutics, told Dermatology Times.

GX-03 Stage 2 Trial Design and Interim Efficacy Data

The ongoing adaptive phase 2 trial is evaluating GX-03 against vehicle in patients with AD, with Bruce Stouch, PhD, serving as lead biostatistician. Following a previously disclosed preliminary review of the first 50 completed subjects, the independent data monitoring committee oversaw a multi-week comprehensive interim analysis examining treatment-response patterns, baseline disease characteristics, and efficacy across prespecified and exploratory end points. Enrollment continued without interruption during the review under the trial's adaptive design, and patients enrolled during this period remain blinded for inclusion in the final stage 2 analysis.¹

In the EASI 1.1-7.0 subgroup (n=14 GX-03, n=18 vehicle), 71.4% (10/14) of patients treated with GX-03 achieved week 4 vIGA-AD success compared with 33.3% (6/18) of patients treated with vehicle, a treatment difference of 38.1 percentage points. Complete disease clearance (EASI 100) was achieved by 28.6% (4/14) of patients treated with GX-03 at week 4 and 35.7% (5/14) at week 8, vs 5.6% (1/18) and 11.1% (2/18) with vehicle, respectively.¹

In a separate subgroup representative of the final stage 2 enrollment criteria (EASI ≥1.1 and Peak Pruritus Numerical Rating Scale [PP-NRS] ≥7), week 4 vIGA-AD success occurred in 61.5% (8/13) of patients treated with GX-03 vs 8.3% (1/12) with vehicle.¹

“In inflammatory skin disease, earlier control can have a meaningful impact on both disease burden and patient quality of life. Seeing rapid responder activity alongside a favorable safety and tolerability profile is encouraging and supports the potential for GX-03 to become an important first-line treatment option if these findings continue to be observed as development progresses,” said Stephen Bresnick, MD, in a previous news release.²

GX-03 Safety Profile and Final Stage 2 Efficacy Endpoints

The final stage 2 design will prospectively enroll approximately 120 to 135 patients across 3 baseline EASI strata (1.1-7.0, 7.1-15.9, and ≥16), with 1:1 randomization maintained within each stratum. Four prespecified efficacy end points of week 4 vIGA-AD success, week 4 EASI 75, week 8 EASI 90, and week 8 EASI 100, will be evaluated using the Hochberg multiple testing procedure, an FDA-recognized method allowing significance to be established across multiple end points while preserving control of type I error.¹

"Doctors don't practice medicine by one end point. Eczema is the perfect example. You have EASI 50% reduction, EASI 75% reduction, and EASI 90% reduction, and if you only use one, you don't get the opportunity to explore the others,” Burnam told Dermatology Times.

In the subgroup representative of the final enrollment criteria (n=13 GX-03, n=12 vehicle), week 4 EASI 75 was achieved by 69.2% (9/13) of patients treated with GX-03 vs 25.0% (3/12) with vehicle, and week 8 EASI 90 was achieved by 53.8% (7/13) vs 16.7% (2/12).¹

No treatment-related serious adverse events have been reported in either arm, and the company reported no treatment-related tolerability issues or study discontinuations to date. Turn Therapeutics said GX-03 continues to demonstrate a favorable safety and tolerability profile consistent with prior reports. Enrollment is expected to complete in the fourth quarter of 2026, and the company said it remains capitalized to support the study through the third quarter of 2027.¹

According to Burnam, the adaptive trial design allowed the company to build on stage 1 findings.

"The purpose of a staged, adaptive clinical trial is to learn from the first stage to strengthen the second," Burnam said in the news release. "GX-03 demonstrated meaningful activity across a wider spectrum of atopic dermatitis severity than we originally anticipated. We believe the optimized stage 2 design strengthens the current study while generating data that could support broader development and future labeling opportunities for GX-03."¹

For dermatologists, the expanded design signals a potential topical option for the mild to moderate AD population. Company leadership positioned GX-03 as a candidate for biologic-level efficacy without the administration burden or systemic immunosuppression associated with injectable therapies. Turn Therapeutics is scheduled to discuss the interim analysis and final stage 2 design on an investor webcast July 7, with Burnam and Hahn presenting.¹

References

1. Turn Therapeutics announces final stage 2 design and data-driven expansion of GX-03 phase 2 program in atopic dermatitis. News release. Turn Therapeutics July 7, 2026. Accessed July 7, 2026. https://ir.turntherapeutics.com
2. Turn Therapeutics reports interim analysis findings and adaptive optimization strategy from phase 2 GX-03 trial in moderate-to-severe atopic dermatitis. News release. Turn Therapeutics. June 1, 2026. Accessed June 7, 2026. https://ir.turntherapeutics.com/news-releases/news-release-details/turn-therapeutics-reports-interim-analysis-findings-and-adaptive

Frequently Asked Questions

What is GX-03 being developed for?
GX-03 is an investigational non-systemic topical therapy under evaluation for atopic dermatitis across the full baseline EASI severity spectrum, according to Turn Therapeutics.

How does GX-03 work?
GX-03 is designed as a targeted, non-systemic topical treatment intended to deliver biologic-level efficacy for atopic dermatitis without systemic immunosuppression.

What did the interim analysis show for GX-03?
Interim stage 1 data showed higher rates of vIGA-AD success and complete disease clearance with GX-03 versus vehicle across baseline EASI strata, supporting expansion of the phase 2 program to a broader patient population.