What is the anticipated timeline for results from the EMPEROR study and subsequent FDA approval?

Timeline outlook

• EMP EROR study read‑out: The pivotal Phase 3 trial will run for a full 52‑week (≈12‑month) treatment period. Assuming the first patient is dosed this month, the primary efficacy and safety data are not expected until mid‑2026 (roughly 12–14 months from the start‑up).
  
• FDA decision: If the data are positive and the company proceeds with a rolling‑submission of the NDA, the agency’s standard “priority” review clock is about 6 months. In the best‑case scenario—fast‑track designation, no major regulatory hurdles—Biogen could see an approval late 2026 to early 2027.

Trading implications

• Near‑term (next 3‑6 months): The market will likely price‑in the “clinical‑trial‑risk” premium. Expect the stock to trade in a tight range around the current level, with modest upside on any early‑phase read‑outs or safety updates.
  
• Mid‑term (12‑18 months): As the 52‑week endpoint approaches, the catalyst‑effect will intensify. A clear efficacy signal could trigger a 30‑45 % rally on the prospect of a first‑in‑class disease‑modifying therapy for Dravet syndrome—an indication with a very small, high‑need patient base and limited competition. Conversely, ambiguous or negative data would likely precipitate a 15‑20 % sell‑off and compress the stock’s valuation multiples back toward historic biotech averages.
  
• Long‑term (post‑approval): Assuming FDA clearance, the drug could command premium pricing and generate a multi‑year revenue runway, supporting a higher valuation (EV/EBITDA > 15×) relative to Biogen’s existing portfolio. Position sizing should therefore be weighted toward a buy on pull‑back after any modest negative data, while taking profits on the upside if the 52‑week read‑out confirms a robust efficacy signal.
  

Bottom line: Anticipate the first meaningful data in mid‑2026, with FDA approval potentially by early 2027. The stock will be highly sensitive to those milestones—plan for a long‑duration, high‑volatility trade, buying on dips and trimming gains as the study progresses toward its endpoint.