FDA Rejects Sentynl’s Menkes Disease Therapy

Rare Daily Staff

The U.S. Food and Drug Administration said it would not approve Sentynl Therapeutics’ experimental therapy CUTX-101 as a treatment for the rare metabolic condition Menkes disease in children.

The agency notified the company that it found manufacturing deficiencies at the facility where CUTX-101 is produced. The facility recently provided responses to the FDA’s September 2025 reinspection, and Sentynl expects to request a meeting with the FDA to discuss resubmitting the CUTX-101 application. The agency’s notification did not identify any safety or efficacy data deficiencies.

Menkes disease is a genetic pediatric disorder caused by mutations in the copper transporter gene ATP7A. The condition is characterized by distinctive clinical features, including sparse, depigmented hair; connective tissue problems; and severe neurological symptoms such as seizures, hypotonia, failure to thrive, and neurodevelopmental delays. Mortality is high in untreated Menkes disease, with many patients dying between 2 and 3 years of age.

CUTX-101 is an experimental copper replacement therapy containing copper histidinate, designed to treat Menkes disease by providing bioavailable
copper to patients with the disorder. The FDA granted the therapy Priority Review.

In December 2023, Sentynl Therapeutics assumed full responsibility for the development and commercialization of CUTX-101 from Cyprium, a subsidiary of Fortress Biotech.

“We believe in the promise of our therapy and are prepared to address the feedback and pursue resubmission promptly,” said Matt Heck, CEO of Sentynl.