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ENROLLING_BY_INVITATIONPHASE2/PHASE3

A Clinical Trial to Investigate Long-term Safety, Tolerability, and Efficacy of Weekly Subcutaneous Doses With TransCon CNP in Children and Adolescents With Achondroplasia

A Phase 2, Multicenter, Long-Term, Open Label Extension Trial Evaluating Safety, Tolerability, and Efficacy of Subcutaneous Doses of TransCon CNP Administered Once Weekly in Children and Adolescents With Achondroplasia

NCT05929807•Ascendis Pharma Growth Disorders A/S

View on ClinicalTrials.gov

Summary

TransCon CNP administered once-weekly in children and adolescents with achondroplasia who have completed a prior TransCon CNP clinical trial. Participants who complete a prior TransCon CNP trial and meet all eligibility criteria will be invited to continue into the long-term open label extension trial to receive 100 µg CNP/kg/week of TransCon CNP. Trial treatment will be completed when the participant reaches 16 years of age for females and 18 years of age for males and have femur and tibial epiphyseal closure. TransCon CNP treatment will continue if femur and tibial epiphyseal closure is not confirmed at the age of 16 years for females, and 18 years for males. Treatment with TransCon CNP will be completed once femur and tibial epiphyseal closure is confirmed by radiographic imaging. The trial duration is individual for each trial participant. Visits will occur every 12-14 weeks throughout the trial.

Eligibility

Age

3 - 15 years

Sex

ALL

Healthy Volunteers

Inclusion Criteria

•Written, signed informed consent of the parent(s) or legal guardian(s) of the participant, and as required by the institutional review board/human research ethics committee/independent ethics committee (IRB/HREC/IEC). For participants who are below the age of consent, a written assent will be obtained in accordance with applicable requirements as required by IRB/HREC/IEC. Upon reaching the legal age of consent, depending on applicable requirements, these participants will be asked to give their own written consent.
•Participants with achondroplasia who have completed a clinical trial with TransCon CNP.
•Parent(s)/legal guardian(s) willing and able to administer weekly SC injections of TransCon CNP and to follow the protocol.
•Considered eligible based on the safety evaluations performed for evaluating stopping/holding rule criteria during the prior TransCon CNP clinical trial.

Exclusion Criteria

•Known or suspected hypersensitivity to the investigational product or related products (trehalose, tris\[hydroxymethyl\]aminomethane, succinate, and methoxy polyethylene glycol \[mPEG\]).
•Have received any dose of prescription medications, investigational medicinal product (other than TransCon CNP).
•Sexually active female participants and female partners of male participants of childbearing potential not using a highly effective form of contraceptive (including oral, injectable, or implantable contraception, or intrauterine device (IUD)) for the entire trial period and for 90 days post end of the trial.
•Participants with serum 25-hydroxy-vitamin D (25OHD) levels of \<50 nmol/L (\<20 ng/mL) at Visit 1 must be on treatment regimen of Vitamin D supplementation.
•Any disease or condition that, in the opinion of the investigator, may make the participant unlikely to fully complete the trial, may confound interpretation of trial results, or may present undue risk from receiving trial treatment. This could include family situations, complications or manifestations, or medications that might impact safety or be considered confounding.

Locations (17)

Ascendis Pharma Investigational Site

Little Rock, Arkansas, United States

Ascendis Investigational Site

Aurora, Colorado, United States

Ascendis Investigational Site

Wilmington, Delaware, United States

Ascendis Investigational Site

Saint Paul, Minnesota, United States

Ascendis Pharma Investigational Site

Columbia Falls, Montana, United States

Ascendis Pharma Investigational Site

Buffalo, New York, United States

Ascendis Investigational Site

Houston, Texas, United States

Ascendis Pharma Investigational Site

Madison, Wisconsin, United States

Ascendis Pharma Investigational Site

Parkville, Victoria, Australia

Ascendis Investigational Site

Linz, Austria

Key Dates

Start Date

June 21, 2023

Primary Completion Date

January 1, 2039

Completion Date

March 1, 2039

Last Updated

October 27, 2025

Enrollment

140

ESTIMATED participants

Conditions

Achondroplasia

Interventions

TransCon CNP

DRUG

A Clinical Trial to Evaluate Efficacy and Safety of TransCon CNP Compared With Placebo in Infants (0 to <2 Years of Age) With Achondroplasia

NCT06079398

Achondroplasia

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ACTIVE_NOT_RECRUITINGPHASE2

An Extension Study to Evaluate Safety and Efficacy of BMN 111 in Children With Achondroplasia

NCT03989947

Achondroplasia

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TERMINATEDPHASE2

A Study Of Safety, Tolerability And Effectiveness Of Recifercept In Children With Achondroplasia

Data Source & Attribution

This clinical trial information is sourced from ClinicalTrials.gov, a service of the U.S. National Institutes of Health.

ClinicalTrials.gov last update: October 27, 2025Data synced to Clareo: March 29, 2026

Modifications: This data has been reformatted for display purposes. Eligibility criteria have been parsed into inclusion/exclusion sections. Location data has been geocoded to enable distance-based search. For the authoritative and most current information, please visit ClinicalTrials.gov.

Neither the United States Government nor Clareo Health make any warranties regarding the data. Check ClinicalTrials.gov frequently for updates.

View ClinicalTrials.gov Terms and Conditions

A Clinical Trial to Investigate Long-term Safety, Tolerability, and Efficacy of Weekly Subcutaneous Doses With TransCon CNP in Children and Adolescents With Achondroplasia

Inclusion Criteria

Exclusion Criteria

A Clinical Trial to Evaluate Efficacy and Safety of TransCon CNP Compared With Placebo in Infants (0 to <2 Years of Age) With Achondroplasia

An Extension Study to Evaluate Safety and Efficacy of BMN 111 in Children With Achondroplasia

A Study Of Safety, Tolerability And Effectiveness Of Recifercept In Children With Achondroplasia

A Study to Evaluate the Efficacy and Safety of Recombinant Human Growth Hormone in Children With Achondroplasia

Lifetime Impact Study for Achondroplasia

Radiological Analysis on Patients With Achondroplasia Disorder