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Evaluating a new treatment for infants with achondroplasia

A Phase 2, Multicenter, Double-Blind, Randomized, Placebo-controlled Trial, Evaluating Safety, Tolerability, and Efficacy of Subcutaneous Doses of TransCon CNP Administered Once Weekly for 52 Weeks in Infants (0 to <2 Years of Age) With Achondroplasia Followed by an Open Label Extension (OLE) Period

PHASE2 · Ascendis Pharma A/S · NCT06079398

This study is testing a new treatment for infants with achondroplasia to see if it helps them grow better compared to a placebo.

Quick facts

PhasePHASE2
Study typeInterventional
Enrollment72 (estimated)
Ages0 Years to 2 Years
SexAll
SponsorAscendis Pharma A/S (industry)
Locations18 sites (Saint Paul, Minnesota and 17 other locations)
Trial IDNCT06079398 on ClinicalTrials.gov

What this trial studies

This Phase 2 clinical trial is designed to assess the safety, tolerability, and efficacy of Navepegritide (TransCon CNP) in infants diagnosed with achondroplasia. The study involves a multicenter, double-blind, randomized approach where participants will receive either the treatment or a placebo once a week for 52 weeks. Infants aged 0 to less than 2 years with genetically confirmed heterozygous achondroplasia will be included in the trial. The primary goal is to determine how well the treatment works compared to a placebo.

Who should consider this trial

Good fit: Ideal candidates for this study are infants under 2 years of age with a clinical diagnosis of achondroplasia confirmed by genetic testing.

Not a fit: Patients who do not have a confirmed diagnosis of heterozygous achondroplasia or are older than 2 years will not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could significantly improve growth and development outcomes for infants with achondroplasia.

How similar studies have performed: Previous studies on similar growth factor treatments have shown promise, but this specific approach is novel.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

* Written, signed informed consent by the parent(s)/caregiver(s) of the participant, and as required by the institutional review board/human research ethics committee/independent ethics committee (IRB/HREC/IEC).
* Male or female younger than 2 years of age at the time of randomization; or for open label sentinel participants, at the time of first administration of IMP.
* Clinical diagnosis of achondroplasia (ACH) with genetic confirmation of heterozygous genotype present during screening.
* Parent(s)/caregiver(s) willing to follow the protocol and instructions provided, including being able to administer weekly subcutaneous injections of trial treatment.
* Compliance to daily Vitamin D supplementation for infants aged 14 days to 1 year. All participants older than 1 year of age with serum 25-hydroxyvitamin D (25OHD) measured below lower limit of reference range at screening should start daily Vitamin D supplementation prior to randomization.
* Considered eligible based on the medical history, physical examination, and the results of vital signs, ECG, imaging, and clinical laboratory tests performed during the screening period.

Exclusion Criteria:

* Known or suspected hypersensitivity to the investigational product or related products (trehalose, tris\[hydroxymethyl\]aminomethane, succinate, and polyethylene glycol \[PEG\]).
* Genetic confirmation of ACH homozygous genotype.
* Premature birth with gestational age \< 32 weeks.
* Premature birth with gestational age 32 to 37 weeks, unless time from birth is \> 6 months at the time of screening and the child is in good nutritional status, defined as gain in body weight expected for age and diagnosis of ACH, as determined by the Investigator and confirmed with the Medical Monitor.
* Anticipated, as assessed by Investigator and confirmed with Medical Monitor, to undergo surgical intervention during trial participation, including cervicomedullary decompression. Evaluation of immediate risk of requiring cervicomedullary decompression surgery will rely on the following assessments:

  * Physical examination (e.g., neurologic findings of clonus, opisthotonus, exaggerated reflexes, dilated facial veins)
  * Evidence of uncontrolled sleep apnea as confirmed by local standard of care assessment (e.g. polysomnography or simple sleep test) performed within 6 months prior to screening.
  * MRI performed at screening indicating presence of severe cervicomedullary compression (CMC) or spinal cord damage. Presence of abnormal MRI T2 signal intensity at and immediately above and below the cervicomedullary junction should be considered high risk for requiring surgery and the participant is not eligible for trial participation.

Common surgeries, such as insertion of grommets, adenoidectomy, tonsillectomy, or myringotomy tube placement are permitted during trial participation.

* Have a growth disorder or medical condition, other than ACH, resulting in short stature or abnormal growth as determined by the Investigator and confirmed with the Medical Monitor.
* Have received any dose of prescription medications and/or investigational medicinal product or device intended to affect stature, growth, or body proportionality (including human growth hormone or vosoritide) at any time.
* Requires or anticipated to require chronic (\> 4 weeks) or repeated treatment (more than twice/year) with oral corticosteroids, or high-dose inhaled corticosteroids during trial participation.
* History or presence of injury or disease of the growth plate(s), other than ACH, affecting growth potential of long bones, including Salter-Harris fracture and recent bone-related surgery, as determined by Investigator and confirmed with the Medical Monitor.
* Have a clinically significant finding indicating abnormal cardiac function, including but not limited to:

  * Repaired or unrepaired coarctation.
  * Moderate or greater complexity congenital heart disease including tetralogy of Fallot, atrioventricular septal defects, truncus arteriosus, total anomalous pulmonary venous return, double outlet right ventricle, or single ventricle heart disease.
  * QTcF ≥ 450 msec on screening 12-lead ECG.
* History or presence of a condition impacting hemodynamic stability (such as autonomic dysfunction and orthostatic intolerance).
* History or presence of the following:

  * Chronic anemia.
  * Chronic renal insufficiency.
  * Chronic or recurrent illness that can affect hydration or volume status, including conditions associated with decreased nutritional intake or increased volume loss.
* History or presence of malignant disease.
* Any disease or condition that, in the opinion of the Investigator, may make the participant unlikely to fully complete the trial, not adhering to trial procedures, may confound interpretation of trial results, or may present undue risk from receiving trial treatment. This could include family situations, comorbid conditions, or medications that might impact safety or be considered confounding.

Where this trial is running

Saint Paul, Minnesota and 17 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Achondroplasia

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.