FDA Grants Fast Track Designation to QRX003 for Peeling Skin Syndrome

The FDA has granted Fast Track designation to QRX003, an investigational topical serine protease inhibitor lotion, for the treatment of peeling skin syndrome (PSS), according to an announcement from Quoin Pharmaceuticals. The designation represents the first Fast Track designation granted for a therapy being developed for PSS.

The regulatory milestone follows the FDA’s July 2026 clearance of Quoin’s investigational new drug (IND) application for QRX003 in PSS. According to the company, the IND was the first submitted to the FDA for the rare genetic skin disorder.

PSS currently has no FDA-approved treatment. Quoin plans to initiate a phase 2/3 clinical study of QRX003 in pediatric and adult patients with PSS in the second half of 2026.

Second Fast Track Designation for QRX003

PSS is the second indication for which QRX003 has received Fast Track designation. In March 2026, the FDA granted Fast Track designation to QRX003 lotion 4% for the treatment of Netherton syndrome.

QRX003 has also received Rare Pediatric Disease designation from the FDA for PSS. For Netherton syndrome, the investigational therapy has received FDA Orphan Drug, Rare Pediatric Disease, and Fast Track designations, as well as Orphan Drug designation in the European Union and Japan.

The FDA’s Fast Track program is intended to facilitate development and expedite the review of therapies for serious conditions with unmet medical needs. The designation can allow for more frequent communication with the agency and rolling review of portions of a regulatory application. Therapies may also qualify for Accelerated Approval or Priority Review if applicable criteria are met.

Phase 2/3 Study Planned

Quoin’s planned phase 2/3 study is expected to enroll up to 12 pediatric and adult patients with PSS across the United States and Europe.

Participants are expected to apply QRX003 twice daily to more than 80% of their body surface area for 48 weeks. An interim data review is planned at 24 weeks.

The company stated that it is targeting a potential 2028 approval for QRX003 in PSS, although the candidate remains investigational and its safety and efficacy will need to be established through clinical development.

The IND application was supported by clinical observations from an ongoing investigator-led pediatric study involving a single patient. According to Quoin, treatment has been associated with improvements in objective disease severity measures, including the Modified Ichthyosis Area Severity Index and Investigator’s Global Assessment, as well as pruritus and the Children’s Dermatology Life Quality Index.

The patient has received QRX003 for more than 15 months, and the company reported that no adverse events have been observed to date. These findings are based on a single treated patient and will require evaluation in a larger clinical study.

“This is an important regulatory milestone for QRX003 and for a community that today has no approved treatment,” Michael Myers, PhD, CEO and cofounder of Quoin Pharmaceuticals, said in the announcement.

Addressing an Unmet Need in Peeling Skin Syndrome

Generalized inflammatory PSS is a rare autosomal recessive genodermatosis associated with loss-of-function variants in the CDSN gene, which encodes corneodesmosin. The resulting disruption of epidermal cohesion leads to excessive shedding of superficial epidermal layers.

Patients may experience chronic skin peeling alongside symptoms including severe pain and pruritus. With no currently approved treatment for PSS, management remains focused on supportive care and symptom control.

QRX003 is designed as a topical serine protease inhibitor and is also in late-stage clinical development for Netherton syndrome. Phase 2/3 whole-body studies of QRX003 lotion 4% are ongoing in patients with Netherton syndrome.

The planned PSS trial will extend the clinical development program into another rare inherited skin disorder with substantial unmet therapeutic need.

References

1. Quoin Pharmaceuticals. Quoin Pharmaceuticals announces FDA Fast Track designation for QRX003 for the treatment of peeling skin syndrome. Published September 22, 2026. The announcement reports the Fast Track designation, planned phase 2/3 trial, and current development status of QRX003.
2. US Food and Drug Administration. Fast Track. Updated January 4, 2024. Accessed September 22, 2026. FDA Fast Track
3. Alajlan G, Alsharif S, Alajlan S, et al. A novel pathogenic variant in the corneodesmosin gene causing generalized inflammatory peeling skin syndrome with marked eosinophilia and trichorrhexis invaginata. Clin Case Rep. 2022;10(7):e06075.