Daily close, T-120 (6/27/25) through T+5. Run-up high $27.44 on 12/5/25, low $20.06 on 10/13/25 (T-120 to T-1). FDA decision 12/12/25. Historical price action, not a forecast.
Positioning before the decision
On Nov 28, 2025, 14 days before the decision date, at-the-money options priced a move of ±7.3% through Dec 19, 2025 (the first listed expiry after the decision; ATM implied volatility 38%). The stock closed +1.8% at the first close across the decision and -0.3% five trading days on. A straddle priced weeks out covers ordinary movement plus the event, so this is the move the options market priced through that expiry, not the event-implied move alone. How this compares across 1,000+ decisions.
Was DAYBUE STIX (trofinetide) approved by the FDA?
Yes. The FDA approved the application for DAYBUE STIX (trofinetide) on December 12, 2025. The primary source is linked on this page.
What was DAYBUE STIX (trofinetide) under FDA review for?
The application covered Rett Syndrome. The FDA approved the application on December 12, 2025.
How did ACAD stock react to the FDA decision?
On the decision day ACAD moved +1.8%. That is the recorded reaction to this specific event -- historical measurement, not a prediction, and not investment advice.