FDA Grants Fast Track Designation to QRX003 Lotion for Rare Netherton Syndrome

Quoin Pharmaceuticals has announced that the US Food and Drug Administration has granted Fast Track designation to QRX003 lotion (4%) for the treatment of Netherton syndrome, a genetic dermatologic disorder characterized by severe skin barrier dysfunction and chronic inflammation.¹ There are currently no FDA-approved therapies for this rare disease.

"We believe that the FDA's decision to grant Fast Track Designation to QRX003 reflects the urgent unmet need faced by patients and families living with Netherton Syndrome," said Michael Myers, PhD, CEO and Co-Founder of Quoin. "Fast Track status enables more frequent communication with the FDA and the potential for accelerated regulatory review pathways, which may help bring the first approved treatment for Netherton Syndrome to patients as quickly as possible."¹

Previous Designations and Data

The therapy has received Orphan Drug Designation from both the FDA and the European Medicines Agency for the treatment of Netherton Syndrome.² QRX003 has also been granted Pediatric Rare Disease Designation by the FDA, which may make the program eligible for a priority review voucher if the drug ultimately receives approval.³

In an open-label, 12-week study, clinical improvements observed during treatment were substantial. At the end of 12 weeks, the subject's Modified Ichthyosis Area of Severity Index (M-IASI) score improved from 18 at baseline to 3, and Worst Itch Numeric Rating Scale (WINRS) dropped from 7 to 2. The Investigator’s Global Assessment (IGA) also improved from “moderate” to “almost clear.”

In early 2025, Quoin shared positive whole-body data from the Investigator Pediatric Netherton Syndrome trial. A pediatric patient using QRX003 saw an improved disease state with visually healed skin and no adverse effects after just 2 weeks of twice-daily application. At baseline, the participant had an average itch score of 5 and an Investigator’s Global Assessment (IGA) score of 7, on scales of 0-10. After 2 weeks of treatment, this was reduced to 1 and 1-2, respectively.

Fulfilling an Unmet Need

Netherton Syndrome is a rare genetic disease caused by mutations in the SPINK5 gene, which encodes the serine protease inhibitor lymphoepithelial Kazal-type inhibitor (LEKTI). Loss of LEKTI function results in dysregulated protease activity in the epidermis, leading to compromised skin barrier integrity, persistent inflammation, and heightened susceptibility to infection. Clinically, patients typically present with widespread erythema, scaling, intense pruritus, and recurrent infections beginning early in life.

The disorder is often associated with atopic manifestations and allergic complications, and patients frequently experience significant impairment in quality of life due to chronic symptoms and systemic complications. Current management strategies largely rely on supportive care measures, including emollients, topical anti-inflammatory therapies, and off-label systemic agents aimed at controlling inflammation or immune dysregulation.

QRX003 is a topical investigational lotion containing a broad-spectrum serine protease inhibitor. Designed to inhibit the kallikrein proteases implicated in Netherton Syndrome pathology, QRX003 aims to restore skin barrier integrity and mitigate key symptoms. Early clinical data demonstrated encouraging therapeutic activity, including rapid and sustained skin healing, resolution of pruritus, and elimination of night-time sleep disturbances.

Next Steps

The drug is currently being evaluated in 2 late-stage clinical trials, recruiting 24 to 30 patients across 6 US and up to 6 international sites. It is designed to assess safety and efficacy across the entire body surface area in affected patients. If successful, the program could represent a significant advance in the management of this rare genetic skin disorder and potentially establish the first FDA-approved treatment specifically indicated for the condition.

References

1. Quoin Pharmaceuticals Announces FDA Grants Fast Track Designation for QRX003 for the Treatment of Netherton Syndrome. News release. Globe Newswire. Published March 11, 2026. Accessed March 11, 2026. https://www.globenewswire.com/news-release/2026/03/11/3253756/0/en/Quoin-Pharmaceuticals-Announces-FDA-Grants-Fast-Track-Designation-for-QRX003-for-the-Treatment-of-Netherton-Syndrome.html

2. Quoin Pharmaceuticals Announces U.S. FDA Grants Orphan Drug Designation for QRX003 in Netherton Syndrome. News release. Quoin Pharmaceuticals. Published October 21, 2025. Accessed March 11, 2026. https://investors.quoinpharma.com/news-releases/news-release-details/quoin-pharmaceuticals-announces-us-fda-grants-orphan-drug

3. Quoin Pharmaceuticals Announces FDA Grants Rare Pediatric Disease Designation for QRX003 in Netherton Syndrome. News release. Global Newswire. Published June 24, 2025. Accessed March 11, 2026. https://www.globenewswire.com/news-release/2025/06/24/3104239/0/en/Quoin-Pharmaceuticals-Announces-FDA-Grants-Rare-Pediatric-Disease-Designation-for-QRX003-in-Netherton-Syndrome.html