QRX003 Meets Primary Endpoint in Netherton Syndrome Trial

Quoin Pharmaceuticals Ltd. reported positive interim results from CL-QRX003-004, its ongoing phase 2/3 study of QRX003 4% lotion in patients with Netherton syndrome, according to a company announcement. Four of 6 participants who completed 12 weeks of treatment achieved a 1-grade or greater improvement in Investigator Global Assessment (IGA) across the treatment area, meeting the prespecified alpha-adjusted primary endpoint (66.7% [4/6]; P = .0087 vs α = .0215). The key secondary endpoint, the Global Statistical Test–Global Impression of Change (GIC), also reached statistical significance at week 12 (mean change, –1.5 [SD, 0.82]; P = .0070 vs α = .0215).¹

There are currently no FDA-approved therapies specifically indicated for Netherton syndrome. QRX003 has received Orphan Drug, Rare Pediatric Disease, and Fast Track designations from the FDA. The interim analysis included the first 6 of approximately 20 evaluable participants planned for CL-QRX003-004. Participants were required to discontinue standard-of-care therapies, including topical and systemic prescription treatments, for the duration of the study. Quoin expects to complete enrollment by the end of 2026 and report topline results in the second quarter of 2027.

CL-QRX003-004 is a phase 2/3, multicenter, baseline-controlled, open-label study evaluating the safety, tolerability, and efficacy of QRX003 4% lotion applied twice daily to the whole body, excluding the scalp, in patients with Netherton syndrome. The study is enrolling participants aged 4 years and older at sites in the US and UK. Treatment continues for 12 weeks, followed by a 4-week post-treatment end-of-study visit.

The interim analysis included the first 6 participants to complete 12 weeks of treatment. The cohort included 3 male and 3 female participants ranging in age from 11 to 52 years.¹

QRX003 Demonstrates Improvements Across Clinician-Assessed Endpoints

For the primary endpoint, 4 of 6 participants (66.7%; 95% CI, 22.28%-95.67%) achieved a 1-grade or greater improvement in IGA across the treatment area at week 12.¹ The result was statistically significant compared with a prespecified null hypothesis of 1 responder (P = .0087 vs α = .0215). Two of the 4 responders achieved a 2-grade or greater improvement in IGA.

On the Ichthyosis Area and Severity Index (IASI), 4 of 6 participants achieved reductions in disease severity of greater than 25%, with improvements ranging from 31% to 87% from baseline. The same 4 participants who responded on the IGA endpoint also demonstrated improvements on IASI.

QRX003 Secondary Endpoints and Safety Findings

On the Worst Itch Numeric Rating Scale (WI-NRS), 3 of 6 participants (50%; 95% CI, 11.81%-88.19%) achieved an improvement of at least 3 points from baseline at week 12 (P = .0623).¹ All 3 participants with moderate to severe pruritus at baseline achieved this threshold, and 1 participant experienced an improvement of more than 6 points.

The WI-NRS is scored from 0 to 10, with higher scores indicating greater itch severity. Quoin stated that the pruritus findings were consistent with previously reported observations from its ongoing pediatric compassionate use program.¹

QRX003 was well tolerated in the interim cohort. No deaths or treatment-related serious adverse events were reported, and no clinically significant ECG, laboratory, or vital sign abnormalities were identified.¹

Michael Myers, MD, chief executive officer and co-founder of Quoin Pharmaceuticals, said the interim findings provide evidence that QRX003 has “the potential to change the course of Netherton Syndrome.”¹

Netherton syndrome is a rare genetic skin disease associated with mutations in the SPINK5 gene and characterized by impaired skin barrier function, persistent inflammation, and increased serine protease activity.¹ QRX003 is an investigational topical serine protease inhibitor being developed to address this increased protease activity.

QRX003 Development Continues as Full Trial Enrollment Progresses

If approved, QRX003 could become the first FDA-approved therapy specifically indicated for Netherton syndrome. Quoin expects to complete enrollment in CL-QRX003-004 by the end of 2026, with topline results anticipated in the second quarter of 2027.

References

1. Quoin Pharmaceuticals reports positive interim data from ongoing phase 2/3 study of QRX003 in Netherton syndrome. Quoin Pharmaceuticals, Inc. Published August 28, 2026. Accessed August 28, 2026. https://www.globenewswire.com/news-release/2026/08/28/3352586/0/en/quoin-pharmaceuticals-reports-positive-interim-data-from-ongoing-phase-2-3-study-of-qrx003-in-netherton-syndrome.html
2. About Quoin Pharmaceuticals Ltd. Quoin Pharmaceuticals. Accessed August 28, 2026. https://quoinpharma.com/company/