The U.S. FDA approved Zycubo (copper histidinate, CUTX‑101) as the first treatment for Menkes disease, a fatal pediatric disorder of copper absorption. The approval granted Sentynl Therapeutics a rare pediatric disease priority review voucher (PRV), with the voucher’s economic arrangements assigned under prior agreements to Cyprium Therapeutics and Fortress Biotech. The approval arrived ahead of the PDUFA date after the sponsor addressed prior manufacturing concerns cited in a complete response letter. Sentynl will lead commercialization; financial terms of the PRV transfer and milestone provisions were disclosed in company filings. Regulatory and commercial materials note the therapy’s potential to alter the natural history of Menkes disease in infants and the strategic value of the PRV for the sponsor and its partners.