Biohaven Stock Surges 37%: FDA Gives Vyglxia a Second Chance After Last Year's Rejection

Biohaven (NYSE: BHVN) stock surged as much as 39% in premarket trading on Thursday, October 22, 2026, after the U.S. Food and Drug Administration accepted the company's resubmitted application for Vyglxia, its experimental treatment for spinocerebellar ataxia — giving the drug a second chance less than a year after the FDA rejected it. Shares were recently up about 37% to around $16.20-$16.35 in premarket action, tracking what Stocktwits described as the stock's biggest single-day gain in more than four years.

What happened, in one paragraph

Biohaven said on Thursday that the FDA has accepted its resubmitted New Drug Application for Vyglxia and considers the resubmission a complete response to the agency's November 2025 rejection letter. The resubmission includes new positive supportive analyses. The FDA has set a target action date in the first quarter of 2027 and plans to hold an advisory committee meeting, with the date to be announced in the near term, to get input from external stakeholders.

The key facts

Stock move: Up 29% to 39% in premarket trading on October 22 — reports ranged from +29% (TipRanks/TheFly) to +39% at $16.35 (Morningstar/Dow Jones), versus a prior close of $11.75
The drug: Vyglxia, an experimental oral treatment for spinocerebellar ataxia (SCA)
The disease: Spinocerebellar ataxia is a rare, life-threatening inherited neurodegenerative disease marked by progressive loss of voluntary motor control and atrophy of the cerebellum and brainstem, affecting balance, coordination, walking and speech
The rejection: The FDA issued a Complete Response Letter in November 2025, declining to approve Vyglxia over concerns about the clinical evidence and study design
The new timeline: FDA target action date in Q1 2027, with an advisory committee meeting planned before then
Cash position: About $270.5 million in cash, marketable securities and restricted cash as of June 30, per Stocktwits

Why it's blowing up

For a clinical-stage biotech, a rejected lead drug is often an existential event — and that is how Biohaven's November 2025 rejection played out. The company had reported that Vyglxia slowed disease progression by 50% to 70% over a three-year period, but the FDA raised concerns about flaws in the study design. After the rejection, Biohaven announced plans to cut annual direct research and development spending by about 60%.

Thursday's acceptance changes the story in one specific, important way: the FDA is saying the updated filing is complete enough to review again. That restarts a review clock many investors had written off. Acceptance is not approval — the agency still has to weigh the evidence, and the planned advisory committee meeting means outside experts will publicly debate the data before the Q1 2027 decision date. But for a stock that closed at $11.75 on Wednesday, the difference between "rejected" and "under review again, with a date" is the entire rally.

The move also landed on a difficult day for the wider market, when tech and AI stocks were dragging the Nasdaq lower. A small-cap biotech jumping more than a third on hard regulatory news stood out sharply against that backdrop.

A second, separate piece of good news

Biohaven has also recently disclosed a regional licensing agreement with Japan's Ono Pharmaceutical covering its MoDE IgG degrader portfolio — BHV-1300, BHV-1310 and BHV-1320 — in Japan, South Korea, Taiwan and Southeast Asia. Reports put the deal at up to $100 million in near-term payments, including $80 million upfront and royalties of about 20% on net sales in the licensed territory, while Biohaven keeps rights in the United States, Europe and China. That is a different program from Vyglxia, but it adds non-dilutive cash and outside validation at the same moment the company's lead drug returns to review.

What's next

Two dates now matter. First, the FDA advisory committee meeting — its date is expected in the near term, and the tone of that public discussion will be the next major catalyst, in either direction. Second, the FDA's target action date in the first quarter of 2027, when the agency is due to decide on Vyglxia again. Until then, investors will also watch Biohaven's cash burn: the company is clinical-stage, loss-making, and funding several programs at once, which is why both the Ono cash and the earlier R&D cuts matter to the story.

This post reports what happened and how markets reacted. It is not financial advice, and it is not a recommendation to buy, sell or hold any security. FDA acceptance of a resubmission is not an approval.

FAQ

Why did Biohaven stock surge on October 22, 2026?

The FDA accepted Biohaven's resubmitted application for Vyglxia, its experimental spinocerebellar ataxia drug, calling it a complete response to the November 2025 rejection. Shares rose 29% to 39% in premarket trading.

What is Vyglxia and what does it treat?

Vyglxia is an experimental oral drug for spinocerebellar ataxia, a rare inherited neurodegenerative disease that progressively damages balance, coordination, walking and speech.

When will the FDA decide on Vyglxia?

The FDA has set a target action date in the first quarter of 2027 and plans to hold an advisory committee meeting before then. Acceptance of the resubmission does not guarantee approval.

Why did the FDA reject Vyglxia the first time?

In November 2025 the FDA issued a Complete Response Letter raising concerns about the clinical evidence and study design supporting the drug's effectiveness, despite Biohaven reporting 50% to 70% slowing of disease progression over three years.