Daily close, T-120 (3/14/25) through T+5. Run-up high $150.71 on 3/14/25, low $113.38 on 4/16/25 (T-120 to T-1). FDA decision 8/29/25. Historical price action, not a forecast.
Positioning before the decision
On Aug 15, 2025, 14 days before the decision date, at-the-money options priced a move of ±6.3% through Sep 5, 2025 (the first listed expiry after the decision; ATM implied volatility 33%). The stock closed -0.3% at the first close across the decision and +6.0% 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 LEQEMBI IQLIK (lecanemab-irmb) - (Maintenance Dosing) approved by the FDA?
Yes. The FDA approved the application for LEQEMBI IQLIK (lecanemab-irmb) - (Maintenance Dosing) on August 29, 2025. The primary source is linked on this page.
What was LEQEMBI IQLIK (lecanemab-irmb) - (Maintenance Dosing) under FDA review for?
The application covered Early Alzheimer's Disease. The FDA approved the application on August 29, 2025.
How did BIIB stock react to the FDA decision?
On the decision day BIIB moved -0.3%. That is the recorded reaction to this specific event -- historical measurement, not a prediction, and not investment advice.