Troriluzole Is Back Under FDA Review for Spinocerebellar Ataxia, and This Time SCA Families May Get a Say

In August 2025, the FDA told Biohaven it no longer needed outside experts to review troriluzole, Investing.com reported from a company filing. Troriluzole is Biohaven's once-daily pill for spinocerebellar ataxia, or SCA. That meeting was not held, and on November 4, 2025 the FDA declined to approve the application.

On October 22, 2026, Biohaven announced that the FDA had accepted its resubmitted application and would decide in early 2027. This time, the company added, the FDA plans to hold an advisory committee meeting. If that meeting goes ahead, people living with SCA and their families can ask to speak in public before the decision.

What the FDA Accepted for Troriluzole on October 22, 2026

Investing.com reported from the company's filing that the FDA accepted the resubmission as a complete response to its November 4, 2025 letter. That acceptance starts a new review. Vyglxia is the brand name Biohaven has proposed. The agency set its goal date in the first quarter of 2027, and Biohaven has not disclosed the exact day.

The resubmission adds what Biohaven called new positive supportive analyses. Neither the company nor the FDA has described those analyses publicly, so outsiders cannot yet judge how well they answer the agency's concerns. Acceptance means the FDA found the file complete enough to review. The agency can still approve the drug, reject it again or extend the review.

Troriluzole was rejected because the FDA did not accept Biohaven's main evidence as an adequate and well-controlled study. That evidence compared 3 years on troriluzole with people in a separate study who were not taking it. The agency published its letter, which lists its reasons in detail.

That comparison came after a setback. Study 206, the placebo-controlled part of the Phase 3 program, followed 218 adults for 48 weeks (NCT03701399 on ClinicalTrials.gov). Both groups worsened by almost the same amount on f-SARA, a 16-point ataxia scale (Potashman et al., Cerebellum 2024). It scores 4 everyday skills: walking, standing, sitting and speech. Biohaven then compared patients who stayed on troriluzole for 3 years with matched patients from CRC-SCA. That US natural history study follows people who are not taking troriluzole, and Biohaven reported 50% to 70% slower worsening on the drug.

The FDA's letter listed several problems with that matched comparison.

• Of the 18 natural history sites, 12 were also troriluzole trial sites, which the FDA said could bias who was enrolled and how unblinded raters scored people.
• By year 3, scores were missing for 52% of treated patients and 79% of comparison patients, and a prespecified check for that gap erased statistical significance.
• Treated patients were scored about 336 days apart and comparison patients 365 days apart, and lining up the timing also erased significance.
• The analysis plan was written in 2024, after Biohaven had seen earlier comparisons, which the FDA said did not count as truly prespecified.
• A separate falls analysis was not prespecified, and inspections found falls had been under-reported and miscoded. Once the data were corrected, the difference was not statistically significant.

The letter called the year-3 difference, 0.79 points on f-SARA, of uncertain clinical meaningfulness. It asked for an adequate and well-controlled study showing an effect on a clinically meaningful endpoint, and it recommended that Biohaven meet with the agency. Biohaven said it was extremely disappointed on behalf of patients and asked for that meeting as soon as possible. Our January analysis walks through the letter in more depth.

How SCA Families Can Speak at the Troriluzole Advisory Committee

An FDA advisory committee is a panel of outside experts that reviews an application in public and votes on questions the FDA poses. The vote does not bind the FDA, though the agency says it generally follows its committees' advice.

The meeting notice will name a contact person and a regulations.gov docket where anyone can file a written comment. Each meeting sets aside time for an open public hearing, where people who register in time can speak briefly. The FDA may hold a lottery when more people ask to speak than the time allows. Briefing documents from the FDA and Biohaven generally go online no later than 2 business days before the meeting.

What a Useful Comment Can Add

Panels hear plenty of statistics in a day of testimony. They hear far less about what a small change on a rating scale means at home. Think of climbing stairs, sitting without support or being understood on the phone. A comment that ties daily life to those 4 f-SARA areas speaks directly to the FDA's question about clinical meaningfulness.

Ataxia families have done this work before. The National Ataxia Foundation and CureDRPLA held a patient-led Patient-Focused Drug Development meeting on September 25, 2020. People with SCA3 also spoke with FDA staff at a listening session on September 22, 2023.

“In neurodegenerative ataxias, stability represents meaningful therapeutic success.”

Jeremy Schmahmann, MD, Massachusetts General Hospital Ataxia Center, written Senate testimony, February 26, 2026. He is a site investigator for Biohaven's troriluzole study and for the CRC-SCA natural history study, and he consults for Biohaven.

Can You Still Get Troriluzole Through Expanded Access?

Possibly, though its status needs checking first. ClinicalTrials.gov lists troriluzole's expanded access program (NCT06034886) as available to adults with confirmed SCA and adequate liver function. That record was last updated on January 9, 2026.

In written testimony to the Senate Special Committee on Aging on February 26, 2026, Dr. Schmahmann said nearly 300 patients were taking troriluzole through the program. He also said the program was about to end. We could not find a public update from Biohaven on the program since then. A neurologist can contact Early Access Care, the program contact listed on ClinicalTrials.gov, at Troriluzole.EAP@earlyaccesscare.com to ask whether it is still accepting patients.

Spinocerebellar Ataxia Trials Open Now, by SCA Type

Only 3 recruiting SCA treatment studies on ClinicalTrials.gov had a US site on October 22, 2026, and all 3 are open to people with SCA6. One is a Phase 3 trial at 3 US hospitals of N-acetyl-L-leucine for SCA6 and other CACNA1A conditions, open to ages 4 and up. IntraBio already sells the drug as Aqneursa for other diseases. The other 2 are small deep brain stimulation studies at UCSF and the University of Florida.

We counted the 217 people treated in Study 206 by SCA type, using its posted results. We then lined those types up against every recruiting SCA study on ClinicalTrials.gov and the types CRC-SCA is enrolling.

For the other types, the CRC-SCA natural history study (NCT01060371) is the main US option, with 14 recruiting US sites and 1 in Montreal. It gives no treatment, but studies like it supply the comparison data SCA drug applications have relied on, including Biohaven's. The SCA trials page lists every open study with its locations.

SCA Treatment Hope in 2027, From Troriluzole to Gene-Silencing Drugs

No medicine is FDA-approved to slow any spinocerebellar ataxia. Troriluzole is the only SCA drug under FDA review, according to our FDA calendar. The agency accepted the resubmission for a full review and chose to put the evidence in front of outside experts in public. Neither step predicts the outcome, but both give the ataxia community a clearer view of how the decision gets made.

Newer programs aim at the faulty genes themselves. Vico Therapeutics is testing VO659, an antisense drug given by spinal injection, in people with SCA1 or SCA3 and in Huntington's disease. Vico said in February 2026 that the FDA had cleared it to begin US testing. Arrowhead's ARO-ATXN2, an RNA-silencing drug for SCA2, has enrolled 39 people in a Phase 1 study with an estimated primary completion of December 2026. Neither has reported results on ataxia symptoms.

Physical therapy is the option with the most trial evidence behind it, though that evidence is weak. A review published in January 2025 found 18 randomized trials with 398 people who had degenerative cerebellar ataxias (Matsugi et al., Frontiers in Neurology). In the 315 people scored on SARA, physiotherapy lowered scores by about 1.4 points, and the authors rated the evidence low to very low certainty. The National Ataxia Foundation's Ataxia Centers of Excellence can connect families with therapists and genetic counselors who know these diseases.

Questions About Troriluzole and SCA

When the Federal Register notice appears, the countdown to register for the open public hearing begins. Families who have already written down what a year of change looks like at home will be ready to use it.