The U.S. Food and Drug Administration approved Zycubo (copper histidinate, CUTX‑101) as the first treatment for Menkes disease, granting Sentynl Therapeutics the initial U.S. approval for a rare pediatric disorder of copper absorption. The approval delivered a Rare Pediatric Disease priority review voucher to the sponsor; Cyprium Therapeutics (Fortress Biotech) remains involved under prior agreements. The clearance followed a manufacturing‑related complete response letter last year and arrived two days ahead of the PDUFA date. For clinicians and developers, the approval establishes regulatory precedent for treating inborn errors of metal metabolism and underscores the continuing role of PRVs in rare‑disease deal economics.