Biohaven Pharmaceutical Holding Co Ltd. (BHVN) saw its stock price plummet 14.50% in pre-market trading on Thursday, as investors reacted to news of a delay in the regulatory review process for one of the company's key drug candidates.

The U.S. Food and Drug Administration (FDA) has extended the Prescription Drug User Fee Act (PDUFA) date for Biohaven's New Drug Application (NDA) for troriluzole, a potential treatment for the rare genetic disease spinocerebellar ataxia. The FDA's Office of Neuroscience informed the company that it plans to hold an advisory committee meeting, although no date has been set. As a result of this extension, the FDA's decision regarding the NDA is now expected in the fourth quarter of 2025, a three-month delay from the original timeline.

This setback for troriluzole, a crucial drug in Biohaven's pipeline, has clearly unsettled investors. The extended review period not only postpones potential revenue from the drug but also introduces additional uncertainty into the approval process. It's worth noting that the FDA did not raise any new safety concerns in its communication with the company. However, for a pharmaceutical company like Biohaven, delays in drug approvals can significantly impact financial projections and market confidence, which is reflected in the sharp stock decline. The company's shares have already experienced substantial losses this year, highlighting the challenges Biohaven faces in bringing its novel treatments to market.