Atossa Therapeutics recently announced that the US Food and Drug Administration (FDA) has granted Rare Pediatric Disease (RPD) designation to (Z)-endoxifen for the treatment of McCune-Albright Syndrome (MAS) in females.

RPD designation is granted 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 RPD designation may be eligible for a Priority Review Voucher (PRV), which can be used to obtain priority review for a future application or may be sold or transferred to another sponsor.

In the last 18-24 months, disclosed PRV sales have ranged from approximately USD 100-USD 205 million.

Steven Quay, M.D., Ph.D., President and Chief Executive Officer (CEO), Atossa Therapeutics, said, "This designation is an important regulatory milestone for Atossa and provides further validation of the potential of (Z)-endoxifen beyond oncology. McCune-Albright Syndrome is a rare and serious pediatric disorder with significant unmet medical need, particularly in young girls affected by hormone dysregulation and early puberty. We believe (Z)-endoxifen has the potential to address key disease drivers and improve outcomes for these patients, while also creating potential non-dilutive value through the Rare Pediatric Disease program.

Dr. Quay continued, "We are pleased to have participated in the Fibrous Dysplasia, McCune-Albright Syndrome Alliance (FD/MAS Alliance) Research Priorities Workshop at Children's Hospital of Philadelphia, with leading clinicians, researchers, and patients, their caregivers, and patient advocacy groups. This workshop was structured to inform and shape the FD/MAS research agenda by integrating the perspectives and challenges faced by patients and their care givers with insight from clinicians and researchers into the current state of science, identifying unmet medical needs and fostering collaboration to accelerate development of new therapeutic options for patients.

Our engagement in this forum underscores our commitment to collaborating with the clinical and patient community as we advance development of (Z)-endoxifen for MAS."

Janet Rea, Senior Vice President, Research and Development, Atossa, said, “RPD designation provides a valuable regulatory pathway and opportunities for enhanced engagement with the FDA as we evaluate development strategies for MAS. We are encouraged by the scientific rationale supporting (Z)-endoxifen in this setting, particularly given its mechanism as a potent SERM/D and its potential to modulate estrogen-driven disease manifestations. We look forward to advancing this program as we further define the clinical development path."