“We appreciate the Agency’s partnership and commitment to expeditiously reviewing our NDA resubmission,” said Matt Heck, CEO, Sentynl. “The acceptance of the application brings us one step closer to a milestone for patients and families who are living with Menkes disease.”

Sentynl resubmitted its revised NDA on November 14, 2025 after receiving a complete response letter (CRL) from the FDA on September 30, 2025, which cited observations regarding the manufacturing site’s cGMP compliance. The CRL did not cite any other approvability concerns, nor did it identify any deficiencies in CUTX-101’s efficacy and safety data, which demonstrate improvement in overall survival for Menkes disease subjects who received early treatment with the therapy.

Menkes disease is a rare X-linked recessive pediatric disease caused by gene mutations of the copper transporter ATP7A. The minimum birth prevalence for Menkes disease is believed to be 1 in 34,810 live male births, and potentially as high as 1 in 8,664 live male births, based on recent genome-based ascertainment. (Estimated birth prevalence of Menkes disease and ATP7A-related disorders based on the Genome Aggregation Database (gnomAD)). The condition is characterized by distinctive clinical features, including sparse and depigmented hair (“kinky 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 2-3 years of age. (Early clinical signs and treatment of Menkes disease – ScienceDirect). Milder versions of ATP7A mutations are associated with conditions other than Menkes Disease, such as Occipital Horn Syndrome and ATP7A-related Distal Motor Neuropathy.