Quoin Wins Second FDA RPD Designation for QRX003 in PSS

Quoin Pharmaceuticals has secured its second Rare Pediatric Disease (RPD) Designation from the US Food and Drug Administration (FDA) for its lead asset QRX003 in the treatment of Peeling Skin Syndrome (PSS). Announced on 8 September 2026, the designation positions Quoin to potentially secure two Priority Review Vouchers (PRVs), with aggregate non-dilutive cash value that CEO Dr Michael Myers estimated could exceed $300 million at current PRV trading values.

QRX003 is a lotion comprising a broad-spectrum serine protease inhibitor. Quoin’s first RPD designation for QRX003 was granted in June 2025 for Netherton Syndrome, with the drug now known under the brand name Qyleki in that indication after meeting its primary endpoint in a Phase II/III trial in August 2026. Quoin has cleared an Investigational New Drug (IND) application with the FDA and expects to initiate a Phase II trial for PSS before the end of 2026, enrolling up to 12 paediatric and adult patients across the US and Europe. Peeling Skin Syndrome causes continual shedding of the top layer of skin, with no currently approved treatments.

The FDA’s RPD program was recently reactivated after a lengthy period in regulatory limbo, restoring the PRV mechanism as a strategic commercial lever for rare paediatric therapeutics. A PRV can be redeemed for priority FDA review of another marketing application or sold to another sponsor, with recent trading prices in the range of $100-150 million per voucher. If Quoin secures both potential PRVs through NDA approvals in Netherton Syndrome and Peeling Skin Syndrome, the two vouchers combined could deliver over $300 million in non-dilutive cash.

The commercial signal is a substantial reinforcement of Quoin’s rare paediatric dermatology positioning and the broader commercial value of the FDA’s reinstated RPD/PRV framework. Non-dilutive PRV monetisation is emerging as a key strategic financing route for small-cap rare disease specialists. Expect Krystal Biotech (Vyjuvek), Amryt Pharma/Chiesi, Castle Creek Biosciences and other rare dermatology specialists to sharpen their positioning through 2027.

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