FDA Accepts Biohaven Ataxia Drug Resubmission, Targets Decision in Early 2027
Key Facts
Biohaven said the U.S. Food and Drug Administration had accepted for review its resubmitted new drug application for VYGLXIA, known as troriluzole, to treat spinocerebellar ataxia, according to a company filing with the U.S. Securities and Exchange Commission. The move returns the application to regulatory review following an earlier letter that concluded the treatment's efficacy had not been established. The company said the resubmitted application includes "new positive supportive analyses," describing the additions submitted to support the application. It added that the FDA had informed it that it considers the resubmission a "complete response" to its previous regulatory letter. The announced action concerns acceptance of the application for review, while a decision on the application remains a later step in the regulatory process.
The FDA had said in its previous letter that "substantial evidence of effectiveness had not been established" for troriluzole in treating spinocerebellar ataxia. The letter included a specific observation about missing functional scale data at the third-year follow-up point. According to the FDA, these data were missing for 52% of participants who received troriluzole. The corresponding proportion of missing data was 79% among members of the U.S. natural history comparison group used in the study. The missing data thus affected both the treatment group and the comparison group, with a higher proportion in the latter at the same assessment point.
Troriluzole targets a disease Biohaven described in an earlier statement as a rare, inherited, life-threatening neurodegenerative disorder for which it said no treatment is available. In a February 2025 statement, the company estimated that about 15,000 people in the United States had spinocerebellar ataxia. It estimated the number of people affected in Europe and the United Kingdom at about 24,000. As for the drug itself, Biohaven explains in its annual report that it is a prodrug cleaved by blood enzymes in the body into riluzole. On the European regulatory front, the company said it decided in March 2025 to withdraw the marketing authorization application for troriluzole. In a separate historical market reaction, Investing.com reported in an article published on 25 April 2025 that Biohaven shares fell as much as 21% following the withdrawal of the European application for "Dazluma."
The U.S. application's return to review comes against a backdrop of high operating spending at Biohaven, according to its financial disclosures. Net cash used in operating activities totaled $609.4 million during 2025, according to the annual report filed with the U.S. Securities and Exchange Commission. That compares with $582.5 million used in operating activities during 2024, reflecting an increase in operating cash outflows between the two years. In a subsequent financial disclosure, the company said cash and cash equivalents totaled $238.0 million as of 30 June 2026. It added that its portfolio of marketable securities totaled $29.8 million on the same date.
As part of reprioritizing its operations following the earlier regulatory rejection, Biohaven had announced a target to reduce annual direct research and development spending by about 60%. The company excluded personnel costs and stock-based compensation from the spending base covered by the reduction target. On commercial funding, its agreement with Ono, announced in October 2026, provides for an $80 million payment at closing. The agreement includes an additional $20 million payment tied to achieving a contractual milestone. Biohaven said achievement of that milestone was expected within a year, according to the agreement announcement. In the next regulatory step for troriluzole, the FDA plans to convene a meeting of its Peripheral and Central Nervous System Drugs Advisory Committee to obtain outside views, according to the company filing. The FDA set the first quarter of 2027 as the target date for action on the resubmitted application.