Ascendis Pharma A/S announced on March 31, 2025, the submission of its New Drug Application (NDA) to the U.S. Food and Drug Administration for TransCon CNP (navepegritide), a novel treatment for children with achondroplasia. The company's innovative therapy has demonstrated multiple clinical benefits beyond simply increasing linear growth.
TransCon CNP is an investigational prodrug of C-type natriuretic peptide (CNP) designed to provide continuous exposure of active CNP to receptors throughout the body, including growth plates and skeletal muscle. The treatment is administered once weekly, potentially offering a more convenient dosing schedule than existing therapies.
Comprehensive Clinical Evidence
The NDA submission is supported by data from three randomized, double-blind, placebo-controlled clinical trials, including the pivotal ApproaCH Trial, with up to three years of open-label extension data. According to the company, the clinical data demonstrates that TransCon CNP treatment was associated with:
- Increased growth velocity
- Reduced health-related burden
- Stronger muscle function
- Straightening of abnormal leg bowing in the majority of treated children
"We are pleased to share clinical data with the FDA demonstrating that, in addition to increased growth velocity, treatment with TransCon CNP was associated with reduced health-related burden, stronger muscle function, and straightening of abnormal leg bowing for the majority of treated children," said Aimee Shu, M.D., Executive Vice President and Chief Medical Officer at Ascendis Pharma.
Dr. Shu further emphasized that the once-weekly administration, combined with these positive outcomes and a safety and tolerability profile comparable to placebo, supports TransCon CNP's potential to be recognized as a best-in-class treatment for achondroplasia.
Understanding Achondroplasia
Achondroplasia is a rare genetic condition affecting more than 250,000 people worldwide. It arises from a systemic fibroblast growth factor receptor 3 (FGFR3) variant that leads to an imbalance in the effects of the FGFR3 and CNP signaling pathways.
While historically viewed primarily as a bone growth disorder, achondroplasia is now understood to have much broader impacts. The FGFR3 variant is expressed in tissues throughout the body, causing serious complications beyond skeletal dysplasia, including:
- Muscular issues: Impaired strength and stamina
- Neurological complications: Enlarged brain ventricles
- Cardiorespiratory problems: Upper airway obstructions and sleep-disordered breathing
- Skeletal issues: Spinal deformities, hip problems, and leg bowing
- Quality of life impacts: Chronic pain, hearing deficits, and chronic ear infections
These complications often persist or worsen into adulthood, significantly affecting quality of life, physical functioning, and psychosocial wellbeing. Many individuals with achondroplasia require multiple surgeries and procedures throughout their lives to address these complications.
Global Regulatory Strategy
Following the U.S. submission, Ascendis Pharma plans to submit a Marketing Authorisation Application (MAA) to the European Medicines Agency (EMA) during the third quarter of 2025, reflecting the company's global approach to bringing this therapy to patients.
TransCon Technology Platform
TransCon CNP is developed using Ascendis Pharma's proprietary TransCon technology platform, which is designed to create new therapies that optimize efficacy, safety, and dosing frequency. The platform enables the creation of prodrugs that predictably release unmodified parent drugs in a sustained manner.
For TransCon CNP specifically, this technology allows for once-weekly administration while maintaining continuous therapeutic levels of CNP, potentially addressing a key limitation of previous approaches to treating achondroplasia.
Potential Clinical Impact
If approved, TransCon CNP would offer a new therapeutic option for children with achondroplasia, potentially addressing multiple aspects of the condition beyond just height. The demonstrated improvements in muscle function and leg bowing suggest that the therapy may help reduce the need for certain surgical interventions and improve overall quality of life.
The safety profile, reported to be comparable to placebo, is particularly important for a therapy that would be administered to children over extended periods during critical developmental stages.
Ascendis Pharma's submission represents a significant step forward in addressing the complex medical needs of children with achondroplasia, potentially offering a comprehensive approach to managing this multifaceted genetic condition.
