FDA Extends Review for Ascendis Pharma's TransCon CNP, Decision Pushed to 2026
Ascendis Pharma's novel therapeutic candidate, TransCon CNP (navepegritide), aimed at treating achondroplasia in pediatric patients, faces a prolonged evaluation period from the U.S. Food & Drug Administration. The FDA has extended its review of the New Drug Application (NDA) by three months, rescheduling the final decision to February 28, 2026. This extension is a direct consequence of a substantial amendment to the NDA, specifically concerning post-marketing requirements. Despite this regulatory deferral, previous clinical findings have highlighted the drug's potential, offering a glimmer of hope for children affected by this rare genetic disorder.
Achondroplasia, a prevalent form of skeletal dysplasia, is characterized by disproportionate short stature, specifically short limbs, alongside a normal trunk size and an enlarged head. This condition originates from a mutation in the FGFR3 gene, which critically impairs the transformation of cartilage into bone, particularly impacting the long bones of the extremities. The FDA's decision to extend the review period underscores the rigorous scrutiny applied to new therapeutic agents, especially those targeting pediatric populations and rare diseases.
Jan Mikkelsen, President and CEO of Ascendis Pharma, confirmed that all outstanding inquiries from the FDA, including a request for a revised post-marketing study protocol, have been addressed. This indicates the company's commitment to fulfilling regulatory requirements and ensuring the comprehensive evaluation of TransCon CNP's safety and efficacy. The extension, while delaying market access, allows for thorough consideration of all submitted data.
Previously, in November, Ascendis Pharma announced the publication of pivotal 52-week results from its ApproaCH Trial in JAMA Pediatrics. The study's findings revealed that treatment with once-weekly TransCon CNP significantly increased annualized growth velocity in children with achondroplasia compared to a placebo. Furthermore, the trial demonstrated improvements in lower-limb alignment, body proportionality, and health-related quality of life, maintaining a safety and tolerability profile comparable to that of the placebo group.
In other developments, earlier in November, the company presented a new aggregated analysis of TransCon PTH (palopegteriparatide) for adults suffering from hypoparathyroidism. This data indicated sustained and clinically meaningful improvements in renal function over a three-year period in both Phase 2 PaTH Forward and Phase 3 PaTHway trials. At the three-year mark, a significant majority of patients were able to forgo conventional therapy, with most achieving normocalcemia, and observing notable improvements in their estimated glomerular filtration rate (eGFR).
The extended review period for TransCon CNP, while a temporary setback, is a standard part of the drug approval process, emphasizing patient safety and long-term effectiveness. The positive results from earlier studies for both TransCon CNP and TransCon PTH suggest a promising future for Ascendis Pharma's pipeline, potentially bringing innovative solutions to patients with rare endocrine disorders.