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# FDA Complete Response on Menkes Disease Drug
- URL: https://www.fdaweb.com/fda-complete-response-on-menkes-disease-drug/
- Published: 2025-10-01T12:00:00.000Z
- Updated: 2026-09-14T15:23:09.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5159965

FDA has issued a complete response letter to Fortress Biotech and its majority-owned subsidiary, Cyprium Therapeutics, regarding their NDA for CUTX-101, a copper histidinate therapy for treating Menkes disease in pediatric patients. The letter cited manufacturing and GMP concerns at the facility producing CUTX-101, according to the companies, adding that no issues were raised with the drug’s clinical efficacy or safety data, which had previously shown improved survival in children treated early with the therapy.

The companies say Sentynl Therapeutics assumed full responsibility 12/2023 for CUTX-101’s development and commercialization. Sentynl is expected to meet with FDA soon to discuss the letter and resubmission plans, following last month’s re-inspection of the manufacturing site.

The companies note that CUTX-101 had been granted a priority review by FDA, reflecting the urgent medical treatment need for Menkes disease, a rare and often fatal genetic disorder affecting copper metabolism. They say the condition occurs in up to one in 8,600 male births and is marked by severe neurological decline, connective tissue problems, and high mortality within the first few years of life.