FDA’s ‘surprising’ uniQure reversal drags down Biohaven

Shares of BioHaven (BHVN) are sliding on Monday after uniQure (QURE) announced that the Food and Drug Administration no longer agrees AMT-130 data is “adequate” to support a Biologics License Application, or BLA. Shares of uniQure have also plunged following the unexpected news regarding its Huntington’s disease gene therapy. Commenting on the setback, Citi says that Biohaven comparison to uniQure may not be applicable, an opinion shared by Raymond James. The latter argues that Biohaven’s troriluzole has “key differences” from the uniCure case.

FDA SETBACK: uniQure received feedback from the U.S. Food and Drug Administration during a recent pre-Biologics License Application meeting regarding AMT-130, an investigational gene therapy for Huntington’s disease. Though final meeting minutes have not yet been received, based on the discussions at the meeting, uniQure believes that the FDA currently no longer agrees that data from the Phase I/II studies of AMT-130 in comparison to an external control, as per the prespecified protocols and statistical analysis plans shared with the FDA in advance of the analyses, may be adequate to provide the primary evidence in support of a BLA submission. This is a key shift from prior communications with the FDA in multiple Type B meetings over the past year. Consequently, the timing of the BLA submission for AMT-130 is now unclear. uniQure expects to receive final minutes within 30 days of the meeting and plans to urgently interact with the FDA to find a path forward for the timely accelerated approval of AMT-130. The FDA granted AMT-130 Breakthrough Therapy designation based upon data from the Phase I/II studies compared to external controls in April 2025 and Regenerative Medicines Advanced Therapy designation in May 2024.

“We are surprised by the FDA’s feedback at the recent pre-BLA meeting, which is a drastic change from the guidance the FDA provided in November 2024 that data from the ongoing Phase I/II studies, compared to a natural history external control, may serve as the primary basis for a BLA submission under the Accelerated Approval pathway,” said Matt Kapusta, CEO. “This news is unexpected, and we are truly disappointed for people living with HD, who have no disease-modifying treatment options for this devastating disease. We strongly believe that AMT-130 has the potential to bring substantial benefit to patients, and we remain fully committed to working with the FDA to determine the best path forward to rapidly bring AMT-130 to patients and their families in the U.S.” In addition to continuing to partner with the FDA on progressing AMT-130 for the treatment of Huntington’s disease, uniQure plans in parallel to progress discussions with other regulatory agencies, including in the European Union and United Kingdom.

COMPARISON NOT APPLICABLE: Citi notes Biohaven is trading lower after uniQure announced the FDA will no longer accept the Phase 1/2 data for AMT-130 in Huntington’s disease compared to an external control as the basis of an application submission. The firm points out that Biohaven’s troriluzole is under review at the FDA’s Center for Drug Evaluation and Research while AMT-130 is under review at the agency’s Center for Biologics Evaluation and Research. This makes a direct comparison potentially not applicable, the firm contends. Citi still views troriluzole’s approval as a “coin flip” but sees added risk following recent updates. The firm has a Buy rating on Biohaven with a $28 price target.

KEY DIFFERENCES: Biohaven shares fell about 25% pre-market amid concern that the FDA’s reversal on uniCure’s Huntington’s gene therapy signals trouble for Biohaven’s troriluzole new drug application in spinocerebellar ataxia, but key distinctions exist, UBS tells investors in a research note. The firm, which has a Strong Buy rating on Biohaven shares, says Biohaven’s filing is under the Center for Biologics Evaluation and Research’s Neurology I division with priority review already granted, while uniCure’s program falls under CBER and has not yet filed, and Biohaven’s oral prodrug of riluzole poses far lower safety and procedural risk than uniCure’s invasive gene therapy approach.

UNLIKELY TO IMPACT REGENXBIO: Stifel analyst Annabel Samimy says that the news regarding FDA’s reversal on the approvability of uniQure’s AMT-130 on Phase 1/2 data on the surface injects another layer of uncertainty into the workings of FDA and their receptivity to gene therapy more specifically. The natural response is to draw parallels for the broader gene therapy space, which encompasses Regenxbio’s (RGNX) rare disease programs. Stifel says that while it is not surprised by the pressure on Regenxbio’s shares, it stands by the quality of the program designs, the data generated to date, and the company’s modernized, scalable, and reproducible manufacturing capacity, of which FDA already completed both the required Pre-License Inspection and Bioresearch Monitoring inspections with no observations or issues, which the firm calls “a relatively unprecedented outcome” in the gene therapy space. The firm has a Buy rating on Regenxbio.

PRICE ACTION: In Monday morning trading, shares of uniQure have plunged almost 56% to $29.83, while Biohaven has dropped about 14% to $14.81.