RARE: FDA approves Fayuvi — first gene therapy for Sanfilippo Type A (MPS IIIA)

[LondonNewsTrader]

Biotech catalyst with a clean first-in-class label — watch the open auction, not the press-release spike.

Reuters / FDA (17 Sep): Ultragenyx (RARE) received FDA approval for Fayuvi (rebisufligene etisparvovec-hopf / UX111), the first therapy for pediatric Sanfilippo syndrome Type A (MPS IIIA). One-time IV AAV9 gene therapy aimed at the underlying SGSH enzyme deficiency; company also flagged a Priority Review Voucher. Shares were up high-single / low-double digits on the print depending on the session window.

Scalper read: rare-disease approvals often gap, then mean-revert once the “PRV + first-approved” premium is auctioned. Focus on opening-range vs AH/PM reference, not chasing the first print. Liquidity can thin fast outside RTH.

Source (fair paraphrase): Reuters 17 Sep 2026 — https://www.reuters.com/business/health ... 026-09-17/
FDA announcement 17 Sep 2026.

Trading the ORB long only if it holds the gap fill level, or fading strength into the first hour?
Anyone marking the PRV as a separate valuation stub, or just treating it as noise for day-trade?