Daily close, T-120 (6/4/25) through T+5. Run-up high $343.99 on 11/18/25, low $271.18 on 9/25/25 (T-120 to T-1). FDA decision 11/19/25. Historical price action, not a forecast.
Positioning before the decision
On Nov 5, 2025, 14 days before the decision date, at-the-money options priced a move of ±4.3% through Nov 21, 2025 (the first listed expiry after the decision; ATM implied volatility 26%). The stock closed -0.5% at the first close across the decision and -0.1% 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 Tarlatamab (AMG 757) - (DeLLphi-304) approved by the FDA?
Yes. The FDA approved the application for Tarlatamab (AMG 757) - (DeLLphi-304) on November 19, 2025. The primary source is linked on this page.
What was Tarlatamab (AMG 757) - (DeLLphi-304) under FDA review for?
The application covered Small cell lung cancer (SCLC). The FDA approved the application on November 19, 2025.
How did AMGN stock react to the FDA decision?
On the decision day AMGN moved -0.5%. That is the recorded reaction to this specific event -- historical measurement, not a prediction, and not investment advice.