Atossa Therapeutics Inc. (NASDAQ: ATOS) received Rare Pediatric Disease designation from the U.S. Food and Drug Administration for its drug candidate (Z)-endoxifen to treat McCune-Albright Syndrome in females, the company announced.

The designation applies to drug candidates intended to treat serious or life-threatening diseases that primarily affect individuals from birth to 18 years of age. Upon approval of a qualifying marketing application, drugs with this designation may be eligible for a Priority Review Voucher, which can be used to obtain priority review for a future application or sold to another sponsor.

In the last 18-24 months, disclosed Priority Review Voucher sales have ranged from approximately $100 million to $205 million, according to the press release.

"This designation is an important regulatory milestone for Atossa and provides further validation of the potential of (Z)-endoxifen beyond oncology," said Steven Quay, Atossa's president and chief executive officer.

McCune-Albright Syndrome is a rare genetic disorder caused by activating mutations in the GNAS gene, leading to mosaic endocrine dysregulation. The disease is characterized by polyostotic fibrous dysplasia, café-au-lait skin spots, and hyperfunctioning endocrinopathies including precocious puberty in children, particularly girls who may begin puberty as early as age two.

Atossa previously received Orphan Drug Designation and Rare Pediatric Disease designation for (Z)-endoxifen for the treatment of Duchenne Muscular Dystrophy from the FDA. The company is a clinical-stage biopharmaceutical company developing novel therapies in oncology and other areas.

(Z)-endoxifen is described as a potent Selective Estrogen Receptor Modulator/Degrader that is currently in development across several clinical settings. The drug is not approved for any indication.