FDA grants accelerated approval to Ascendis’s once-weekly YUVIWEL for achondroplasia

Ascendis Pharma won accelerated approval from the U.S. Food and Drug Administration on Feb. 27 for YUVIWEL (navepegritide; developed as TransCon CNP), a once-weekly injectable indicated to increase linear growth in children aged 2 years and older with achondroplasia who have open epiphyses. The company said it expects to make the therapy available to U.S. prescribing physicians in the early part of the second quarter of 2026.

Ascendis described YUVIWEL as the "first and only once-weekly treatment indicated to increase linear growth in children 2 years of age and older with achondroplasia with open epiphyses and the only one to provide continuous systemic exposure to CNP over the weekly dosing interval." Regulators granted approval under the FDA’s Accelerated Approval Program, meaning continued approval may depend on verification of clinical benefit in post-approval confirmatory trials.

The FDA’s decision was based on improvements in annualized growth velocity measured in Ascendis’ clinical package, which the company says included three randomized, double-blind, placebo-controlled trials and up to three years of open-label extension data. The pivotal ApproaCH trial was published in JAMA Pediatrics, and Ascendis cited a 52-week randomized study in children aged 2 to 11 that showed a statistically significant improvement in annualized growth rate versus placebo.

Achondroplasia, the most common form of short-limbed dwarfism, is caused by a mutation in the FGFR3 gene and affects an estimated 1 in 15,000 to 40,000 newborns, according to the National Institutes of Health. For families and clinicians the new approval expands therapeutic choices: BioMarin’s Voxzogo remains the only other FDA-approved drug for the condition but requires daily dosing, a difference Ascendis and analysts say may influence prescribing patterns.

The company also announced that the FDA issued a Rare Pediatric Disease Priority Review Voucher with the approval. "With this approval, the FDA also issued a Rare Pediatric Disease Priority Review Voucher (PRV), which confers priority review to a subsequent drug application that would not otherwise qualify for priority review," Ascendis’ release said, noting the program is designed to encourage development of new drugs for rare pediatric diseases.

Safety considerations will shape the rollout. Ascendis posted the following "IMPORTANT SAFETY INFORMATION": "YUVIWEL may cause serious side effects, including risk of low blood pressure. If your child experiences a decrease in blood pressure or symptoms of low blood pressure (dizziness, feeling tired, and/or nausea) while being treated with YUVIWEL, call your child’s healthcare provider. The most common side effects of YUVIWEL include injection site reactions (redness, itching, skin discoloration, bleeding, swelling, bruising, pain, and blistering)."

Ascendis plans to support patients through its Ascendis Signature Access Program, offering treatment navigation and financial assistance for eligible families. The company faces the practical task of ensuring specialty prescribing pathways, insurer prior authorization, and equitable access for a rare pediatric population that already encounters systemic barriers to care.

Market watchers signaled commercial potential but cautioned on clinical tradeoffs. "Around 20% of patients do not do well on Voxzogo and could consider switching," TD Cowen analyst Yaron Werber said, and he estimated peak sales of 772 million euros for YUVIWEL in 2032.

Because the approval is accelerated and hinged on a surrogate endpoint of growth velocity, public health experts will watch confirmatory trials closely for evidence that height gains translate into meaningful long-term benefits in function, respiratory health, or quality of life. For families and clinicians, the new option widens the conversation about medical management of achondroplasia while underscoring the ongoing need for transparent data, affordable access, and equity in rare pediatric care.