The FDA approved Zycubo (copper histidinate, CUTX‑101) as the first treatment for Menkes disease, a fatal pediatric copper‑absorption disorder; approval generated a pediatric rare disease priority review voucher transfer agreement tied to prior developer arrangements. The approval followed manufacturing questions earlier in the review and arrived just before the PDUFA target date. Separately, the FDA extended review of Travere Therapeutics’ supplemental NDA for FILSPARI (sparsentan) in focal segmental glomerulosclerosis (FSGS), moving the PDUFA action date out by three months to April 13, 2026, after requesting additional clinical‑benefit characterization. The extension signals the agency’s continued focus on benefit characterization for rare disease label expansions. Taken together, these actions show an active regulatory calendar for rare disease therapies: one first‑in‑class approval reached the market while another candidate awaits further agency‑requested evidence.