An FDA Advisory Committee meeting — usually shortened to "AdCom" — is a one-day public hearing where a panel of independent experts reviews a drug application and votes on whether the agency should approve it.
The vote is non-binding. The FDA can override its own AdCom (and occasionally does). But in practice, the agency follows the committee's recommendation roughly 75–85% of the time.
When does an AdCom happen
Not every drug gets an AdCom. The FDA calls one when there is genuine clinical uncertainty — a novel mechanism, a controversial trial design, mixed efficacy data, or significant safety questions. Routine approvals skip the committee step.
When called, an AdCom is typically scheduled 6–12 weeks before the PDUFA action date. The agency posts the date on its Advisory Committee Calendar and publishes a Federal Register notice 15+ days in advance.
The day-of structure
A typical AdCom day:
- Morning: FDA staff presents the agency's review of the application
- Late morning: Sponsor presents efficacy + safety case
- Lunch break: Committee deliberates internally
- Afternoon: Public comment period (patients, advocates, sometimes researchers)
- Late afternoon: Committee votes on specific questions
The briefing documents are the alpha
Two days before the AdCom, the FDA publishes both its own briefing document and the sponsor's. These often contain new analyses not previously disclosed — most importantly, the FDA's own perspective, which is frequently more skeptical than the sponsor's.
The briefing-doc drop is one of the most volatile moments in biotech trading. Stocks routinely move 20–40% in either direction on the morning the documents post.
What traders watch for
- The FDA's tone in its briefing doc (questioning vs. neutral vs. supportive)
- The specific questions the agency poses to the committee (the framing predicts the vote)
- Historical track record of the specific division reviewing the drug
- Composition of the committee — some committees are known to be more conservative
Common AdCom outcomes
- Unanimous yes — usually leads to approval; modest stock pop
- Split yes (e.g., 8–6, 12–4) — most common; nervous approval
- Split no (e.g., 4–10) — usually leads to CRL; large stock drop
- Unanimous no — almost always CRL; stock can drop 40–70%
Recent examples worth knowing
The committee structure and tone shifts over time. Recent AdComs that meaningfully reset expectations:
- June 2021 — Aduhelm (Biogen) AdCom voted 10–0 against approval; FDA approved anyway, prompting three committee resignations
- September 2022 — Spinraza expansion AdCom voted positively despite mixed data
- 2024+ — Increasing FDA willingness to convene AdComs on accelerated-approval confirmatory data
The Yeji catalyst feed surfaces every confirmed AdCom date and links to the FDA's briefing-document page when posted.