Mezzion Pharmaceuticals Inc, a US-based clinical-stage rare disease biopharmaceutical company developing the first treatment specifically for people born with single ventricle congenital heart disease (SV-CHD) who are living with Fontan circulation, announced on Wednesday that it has received a Notice of Allowance from the United States Patent and Trademark Office (USPTO) for a key US patent application from the company's 2020-filed FUEL patent family, covering the use of udenafil to improve exercise capacity in Fontan patients.

The allowed patent includes broad, age-agnostic method-of-use claims covering chronic, twice-daily oral administration of udenafil (or a pharmaceutically acceptable salt) in Fontan patients to improve exercise capacity, with important dependent claims extending to additional cardiopulmonary exercise testing (CPET) endpoints.

The patent is expected to have a baseline expiration date of 24 July 2040. Subject to FDA approval of udenafil and regulatory review, Mezzion anticipates that the patent will be eligible for listing in the FDA's 'Orange Book' and for patent term extension of up to five years, capped at 14 years from approval, with additional six-month paediatric exclusivity potentially extending US protection into the early 2040s.

Mezzion Pharmaceuticals Inc is a subsidiary of South Korea-based Mezzion Pharma Co Ltd (KOSDAQ:140410).