FDA accepts Biohaven’s troriluzole resubmission

The Food and Drug Administration accepted Biohaven's resubmitted new drug application for troriluzole, proposed as Vyglxia, in spinocerebellar ataxia, according to the company's October 22 Securities and Exchange Commission filing. Biohaven shares jumped 25% to as much as 36% Thursday morning.

The agency considers the resubmission a complete response to its November 4, 2025 complete response letter, and it assigned a user fee goal date in the first quarter of 2027. The FDA also plans to convene the Peripheral and Central Nervous System Advisory Committee; the committee meeting date will be forthcoming in the near term. The resubmission includes new positive supportive analyses.

Troriluzole is meant for spinocerebellar ataxia, a group of rare genetic disorders characterized by progressive loss of control over movement, including balance, coordination and speech. No FDA-approved therapy currently exists for the condition. The original application was rejected in November 2025. In its complete response letter, the FDA cited "issues that can be inherent to real-world evidence and external control studies including potential bias".

Before the Phase 3 study design was finalized, the FDA had told Biohaven that "a large and robust treatment effect would be needed to overcome the biases of an externally controlled trial, in order for it to be used as the primary basis for substantial evidence for effectiveness," according to a Biohaven press release. Biohaven believed it achieved that goal. After the rejection, the company said it believes "the statistical significance and clinical meaningfulness achieved on the primary endpoint and eight consecutive secondary endpoints in 206-RWE . . . clearly met criteria of 'a large and robust treatment effect'".

Biohaven CEO Vlad Coric said after the rejection: "We are extremely disappointed on behalf of patients by this action from the Office of Neuroscience at FDA. Beyond substantial evidence of safety and efficacy, patients with rare diseases also deserve an efficient, fair and flexible regulatory process that aligns with the urgency of their high unmet medical needs".

The submission relies on study 206-RWE, a three-year real-world evidence study that compared troriluzole with a natural history database. The Phase 3 portion missed its primary endpoint, f-SARA, a modified scale for spinocerebellar ataxia that focuses on sitting, standing, walking and talking. However, comparisons to natural history controls showed a 50% to 70% slower rate of decline for patients taking 200 mg, representing a delay of 1.5 to 2.2 years over three years, according to William Blair.

Analysts welcomed the advisory committee plan. TD Cowen's Tyler Van Buren wrote that the meeting "substantially increases the probability of approval." RBC Capital Markets' Leonid Timashev said the FDA's recent shift toward more flexible rare disease reviews "opens a real possibility" Vyglxia could reach market, though he cautioned that its chances depend "largely on how extensive those flexibility changes have been".

Biohaven has faced regulatory setbacks elsewhere. The company withdrew a European marketing application after evaluators there questioned its supportive evidence. After the U.S. rejection, Biohaven cut research and development spending by 60%.

Update, October 23, 2026

AllSci reported that the November 2025 complete response letter also cited design flaws and unmeasured confounding factors, in addition to potential bias. AllSci said about a year passed between the letter and the resubmission acceptance, and it noted Arrowhead Pharmaceuticals’ ARO-ATXN2 is in Phase 1 testing for spinocerebellar ataxia type 2 (NCT06672445). AllSci also wrote that Biohaven was spun off from the original Biohaven in October 2022, when Pfizer acquired its migraine-focused CGRP business for about $11.6 billion; the independent company kept troriluzole.

Yahoo Finance reported Biohaven closed at $14.69, up 25.02%, and that Baird reiterated an outperform rating and raised its price target to $48 from $42. Biohaven also announced a licensing and collaboration agreement with Ono Pharmaceutical for its MoDE pan IgG degrader portfolio in Japan, South Korea, Taiwan and ASEAN countries, with $100 million in near-term payments ($80 million at closing and $20 million upon a milestone) plus 20% royalties on net sales in the territory. Insider Monkey data cited by Yahoo Finance showed 47 hedge funds held Biohaven in the second quarter, unchanged from the first quarter, but combined holdings rose 94% year over year to $667 million from $343 million.

Update, October 23, 2026

Simply Wall St reported that Biohaven has almost no current revenue, is loss-making, and its research-heavy model spans immunology, neuroscience, and oncology; it also has cash runway under one year, minimal sales, recent stock dilution, and share-price volatility. The firm said the Ono Pharmaceutical MoDE pan IgG degrader licensing deal helps define regional responsibilities and may lessen pressure on Biohaven to finance every program itself. Its community fair-value estimates for Biohaven range from $22.73 to $69.82, based on only two individual views.