GX-03 Cuts Itch-Related Cytokine IL-31 by Nearly 68% in AD Model

Turn Therapeutics Inc (Nasdaq: TTRX) announced peer-reviewed preclinical data showing GX-03, its investigational non-systemic topical therapy containing extended-release polyhexanide for atopic dermatitis (AD), reduced inflammatory and itch-related cytokines in a murine dermatitis model. Pretreatment with GX-03 lowered interleukin (IL)-36α and IL-36γ expression by approximately 50% each and IL-31, a cytokine closely associated with itch, by nearly 68%. Clinical dermatitis severity was also reduced by 66% among GX-03-pretreated animals compared with untreated controls.¹

The findings evaluated the inflammatory response that developed when GX-03 was applied before a standardized bacterial skin challenge. The preclinical results provide mechanistic evidence supporting further investigation of GX-03, which is currently in clinical development for AD.¹

GX-03 Pretreatment Reduces Dermatitis Severity and IL-31

The study evaluated 40 mice that received either no pretreatment or 4 days of topical GX-03 before standardized exposure to Staphylococcus aureus, a bacterial challenge used to induce AD-like skin inflammation. Following predefined exclusions, 18 animals in each group were included in the final analysis. The research was conducted at Altogen Labs under an Institutional Animal Care and Use Committee-approved protocol.¹

Clinical dermatitis severity, measured using the validated Investigator Global Assessment for Atopic Dermatitis (vIGA-AD), decreased from a mean score of 2.44 in untreated animals to 0.83 in GX-03-pretreated animals, representing a 66.0% reduction.¹

GX-03 pretreatment was also associated with reductions in several cytokines measured following the bacterial challenge. IL-36α expression decreased by 49.9% and IL-36γ by 50.9%. IL-36 is involved in amplifying inflammatory responses in the skin. IL-31, a cytokine closely associated with pruritus in inflammatory skin diseases such as AD, decreased by 67.7% compared with untreated controls.¹

A key feature of the experimental design was the timing of GX-03 administration. Rather than administering the therapy after inflammation had developed, investigators applied GX-03 before S aureus exposure and subsequently measured the inflammatory response. This allowed researchers to examine whether modifying the local skin environment before the challenge affected the magnitude and pattern of inflammation that followed.¹

Selective Effects on Inflammatory Cytokines

GX-03 did not produce comparable reductions across every cytokine evaluated. IL-4 expression decreased by 16.7% in GX-03-pretreated animals, whereas IL-13 did not differ significantly between groups. The findings demonstrated a selective pattern of cytokine reduction rather than uniform suppression of all inflammatory signals measured in the study.¹

No local irritation, dryness, redness, barrier disruption, or other adverse skin findings were observed during the 4-day GX-03 pretreatment period. These observations were limited to the preclinical model and pretreatment period and do not establish the safety or efficacy of GX-03 in patients with AD.

The findings build on previously published Turn Therapeutics research. GX-03 is designed as a non-systemic therapy that acts locally in the skin and is currently being evaluated in a randomized, double-blind, vehicle-controlled clinical trial in AD.²

Findings Support Continued Clinical Investigation of GX-03

Bradley Burnam, Chief executive officer of Turn Therapeutics, highlighted the timing of GX-03 administration and the reductions in IL-36 and IL-31 as notable aspects of the findings.

"In-vivo, GX-03 strongly reduced IL-36, a key early driver of the inflammatory cascade, as well as IL-31, a major driver of itch. It also reduced IL-4, an important inflammatory signal. Rather than targeting inflammation only after it is already established, GX-03 was present before the challenge and substantially reduced the inflammatory response that followed skin challenge. We believe this supports a fundamentally different approach: modifying the local skin environment upstream, before the inflammatory cascade takes hold."²

We believe this supports a fundamentally different approach: modifying the local skin environment upstream, before the inflammatory cascade takes hold. — Bradley Burnam, chief executive officer of Turn Therapeutics

Although the study provides mechanistic evidence for GX-03 in an experimental model, whether these cytokine reductions translate into clinically meaningful improvements in patients with AD will require evaluation in human clinical trials.

References

1. Burnam B, Bresnick S. Effects of extended-release polyhexanide on inflammatory cytokine expression and disease severity following Staphylococcus aureus exposure in a murine dermatitis model. Life (Basel). 2026;16(8):1369. doi:10.3390/life16081369
2. Turn Therapeutics announces new peer-reviewed research showing GX-03 selectively reduces key drivers of skin inflammation and itch. News release. Turn Therapeutics Inc. August 20, 2026. Accessed August 20, 2026. https://www.businesswire.com/news/home/20260820905760/en/Turn-Therapeutics-Announces-New-Peer-Reviewed-Research-Showing-GX-03-Selectively-Reduces-Key-Drivers-of-Skin-Inflammation-and-Itch