Ascendis Pharma Shares Dip on FDA Delay for Key Dwarfism Drug
The U.S. regulator has extended the review period for TransCon CNP by three months, pushing a potential approval to late February 2026 and creating uncertainty for a cornerstone of the company's growth strategy.
Shares of Ascendis Pharma (NASDAQ: ASND) fell in Tuesday trading after the company announced that U.S. regulators have delayed the review of its highly anticipated drug for achondroplasia, the most common form of dwarfism. The stock slipped approximately 1.1% to $206.65 after the Danish biopharmaceutical firm disclosed that the Food and Drug Administration (FDA) extended the Prescription Drug User Fee Act (PDUFA) goal date for TransCon CNP by three months to February 28, 2026.
The delay introduces a significant pause in the company’s plans to launch what analysts expect to be a "blockbuster" therapy, a designation for drugs generating over $1 billion in annual sales. TransCon CNP is a cornerstone of Ascendis's "Vision 2030," a long-term strategy aiming for over €5 billion in yearly product revenue. The setback postpones a critical potential revenue stream and creates near-term uncertainty for investors who had been anticipating an approval by the original November 30, 2025 deadline.
According to a company press release, the FDA classified information submitted by Ascendis on November 5 regarding post-marketing requirements as a "major amendment" to its New Drug Application (NDA), automatically triggering the three-month extension to allow for a full review of the new data.
"We have responded to all outstanding requests from the FDA, including the request for a revised protocol for the post-marketing study," said Jan Mikkelsen, Ascendis Pharma's President and CEO, in a statement. "We are committed to working diligently with the FDA to finalize elements of the post-marketing requirement, with the goal of bringing this innovative therapy to patients in the U.S. as soon as possible."
TransCon CNP is designed to treat children with achondroplasia and, if approved, would enter a market currently dominated by BioMarin Pharmaceutical's Voxzogo, the only FDA-approved therapy for the condition. Ascendis aims to differentiate its product with a once-weekly dosing schedule, compared to Voxzogo's daily injection, which could offer a significant convenience advantage for patients and caregivers. Clinical trial data from the pivotal ApproaCH study showed TransCon CNP led to a superior annualized growth velocity compared to a placebo.
Analysts have been largely bullish on Ascendis, with an average price target of $255.97, reflecting high expectations for its pipeline. Just a day before the announcement, analysts at TD Cowen reiterated a Buy rating on the stock, citing confidence in the drug's eventual approval. The unexpected delay, while procedural, tests investor patience and slightly de-risks the competitive position of BioMarin for at least another quarter.
The market capitalization of Ascendis stands at approximately $12.77 billion, and the company's financial performance has been closely watched. In its third-quarter results reported on November 12, Ascendis posted revenues that narrowly beat forecasts, but also a wider-than-expected loss per share, underscoring the company's reliance on future product launches to achieve profitability.
While the delay is a setback, the FDA's request for more information on post-marketing studies, rather than efficacy or safety data, may suggest the core application remains solid. Investors and analysts will now be closely watching for a final decision in late February, an event that remains a pivotal catalyst for Ascendis Pharma's long-term valuation and its ambition to become a major player in the rare disease market.