What is an FDA adcom?

An adcom, shorthand for an FDA advisory committee meeting, is a session where a panel of outside experts convened by the agency discusses a pending application and, usually, votes on a question the agency has put to them.

The vote does not approve a drug, reject one, or oblige the agency to do anything. The regulation governing these meetings says so in a single sentence: "The Commissioner has sole discretion concerning action to be taken and policy to be expressed on any matter considered by an advisory committee."

Worth stating plainly, because the headlines read the other way. "FDA panel rejects" is the standard construction and it describes something that did not happen. The agency decides separately, afterwards, on a record that includes far more than the meeting.

Two meetings from this July make the gap concrete, because they went opposite ways and neither one settled anything.

Two votes, one committee, two days apart

On 29 July the Cellular, Tissue and Gene Therapies Advisory Committee considered Capricor's deramiocel for cardiomyopathy in Duchenne muscular dystrophy. The committee voted 3 for, 9 against, 0 abstain.

The next day the same committee took up Replimune's RP1 in advanced melanoma and voted 10 to 3 the other way. Both meetings were announced ahead of time in the Federal Register. Capricor's and Replimune's notices each name the product, the application number and the agenda.

What happened next did not follow the votes the way the headlines implied it would.

RP1 was granted accelerated approval on 6 August, four days after its goal date of 2 August had passed with no announcement at all. We wrote about that absence at the time. Deramiocel's goal date is 22 August, the day this went up, and as of publication the agency had announced nothing. A favorable vote produced four days of silence. An unfavorable vote produced an application still under review three weeks later.

Neither committee voted on approval

This is the part that gets lost, and both companies said so in their own releases.

Replimune's question, verbatim from the meeting: "Are the efficacy results from IGNYTE evaluable and clinically meaningful?" That is a question about whether a single-arm trial can be read at all — not about whether the drug should be sold.

Capricor's panel was asked whether the evidence supported effectiveness in DMD cardiomyopathy. The company's release notes that the question "addressed a narrower indication than Capricor had proposed and did not include a vote on Deramiocel's overall benefit-risk profile", and that a separate discussion of upper limb function went the company's way.

So one panel voted on whether a trial was interpretable, and the other on effectiveness in a slice of the indication the sponsor had asked for. Neither voted on approval, because neither was asked to. The wording of these questions is published in the Federal Register notice before the meeting, which means you can read the actual question yourself before anyone tells you what the vote meant.

How often does the agency follow the advice?

Researchers matched advisory committee votes from 2010 to 2021 against the FDA actions that followed, through 30 November 2022, and found the agency's action aligned with the committee's vote in 262 of 298 cases — published in JAMA Health Forum in 2023.

Two things inside that number matter more than the number.

The first is the direction of the exceptions. When the agency and its advisors diverged, the FDA was more likely than the panel to favor approval, not less. A negative vote is not the ceiling on the outcome that most people assume it is. The same study found the agency usually did not reconvene advisors before approving drugs that had received a negative vote.

The second is what the figure cannot do. It is a base rate across a decade of applications. It is not the probability that any particular drug follows its panel, and treating it that way is how a general statistic gets mistaken for a specific forecast.

Where you read this for yourself

Advisory committee meetings are among the best-documented events in the whole regulatory calendar, and almost all of it is free.

• Before. 21 CFR 14.20(a) requires a Federal Register notice at least 15 days in advance, listing every agenda item and whether it will be heard in open or closed session. The notices are concrete: the amended notice for the Replimune meeting gave the running time, 9:30 a.m. to 4:30 p.m. Eastern, and a YouTube link to watch it live.
• After. 21 U.S.C. 355(n)(7) gives the agency 90 days from a panel's recommendation to review its conclusions and notify the affected persons of the final decision — or of the reasons no decision has been reached.

Read that last one carefully, because it is narrower than it first appears. "Affected persons" means the applicant. The clock is real and the documentation requirement is real, but neither is a promise that you will hear anything on day 90.

The vote is not the last checkpoint either

Avacopan, sold as TAVNEOS, was approved on 7 October 2021 after a contentious advisory committee meeting that May. In April 2026 the FDA's drug center proposed to withdraw that approval, on the grounds that there is a lack of substantial evidence of effectiveness and that the application "contains untrue statements of material fact" about how the pivotal study's data were analyzed. The applicant has an opportunity for a hearing; a proposal to withdraw is not a withdrawal.

The narrow lesson for someone holding the stock is not the misconduct allegation. It is that the notice describes reviewers who had "identified a variety of issues that might preclude approval" during the original review, aired publicly at that 2021 meeting, and it cites the transcript of the meeting as a reference. The doubts were on the record five years before they became a withdrawal proposal. The meeting was where they became readable.

What to watch

• The voting question, published in the notice before the meeting. It is usually narrower than the headline the vote will generate, and the gap between the two is the whole story.
• Whether the agency reconvenes advisors after a negative vote. Usually it does not.
• Goal dates, as goals. Deramiocel's is today. One can pass without anything happening, as RP1's did three weeks ago.

An advisory committee is the one day when the FDA's own reviewers argue in public about a drug you can buy shares in. The tally at the end is the least informative thing that happens in the room.

This is analysis, not investment advice. Nothing here is a recommendation to buy or sell any security.