Daily close, T-120 (4/23/25) through T+5. Run-up high $614.79 on 5/26/25, low $483.07 on 6/10/25 (T-120 to T-1). FDA decision 10/8/25. Historical price action, not a forecast.
Positioning before the decision
On Sep 24, 2025, 14 days before the decision date, at-the-money options priced a move of ±6.1% through Oct 10, 2025 (the first listed expiry after the decision; ATM implied volatility 36%). The stock closed -3.3% at the first close across the decision and -1.8% 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.
Decision facts
FDA decision date2025-10-08
DrugLibtayo (cemiplimab-rwlc)
IndicationHigh-risk cutaneous squamous cell carcinoma (CSCC) after surgery
Was Libtayo (cemiplimab-rwlc) approved by the FDA?
Yes. The FDA approved the application for Libtayo (cemiplimab-rwlc) on October 8, 2025. The primary source is linked on this page.
What was Libtayo (cemiplimab-rwlc) under FDA review for?
The application covered High-risk cutaneous squamous cell carcinoma (CSCC) after surgery. The FDA approved the application on October 8, 2025.
How did REGN stock react to the FDA decision?
On the decision day REGN moved -3.3%. That is the recorded reaction to this specific event -- historical measurement, not a prediction, and not investment advice.