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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

Status
Enrolling by invitation
Phases
Phase 2Phase 3
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT05929807
Acronym
AttaCH
Enrollment
140
Registered
2023-07-03
Start date
2023-06-21
Completion date
2039-03-01
Last updated
2026-08-17

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Achondroplasia

Keywords

Achondroplasia, Dwarfism

Brief 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.

Interventions

TransCon CNP drug product is a lyophilized powder in a single-use vial. Prior to use, the lyophilized powder is reconstituted with sterile water for injection and administered by subcutaneous injection via syringe and needle.

Sponsors

Ascendis Pharma Growth Disorders A/S
Lead SponsorINDUSTRY

Study design

Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE

Intervention model description

Patients will roll over from previous TransCON CNP clinical trials

Eligibility

Sex/Gender
ALL
Age
3 Years to 15 Years
Healthy volunteers
No

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.

Design outcomes

Primary

MeasureTime frameDescription
Safety and TolerabilityThrough trial completion, an average of 10 yearsIncidence of Treatment-Emergent Adverse Events
Height Z-scoresThrough trial completion, an average of 10 yearsNumber of standard deviations

Secondary

MeasureTime frameDescription
Annualized Growth VelocityThrough trial completion, an average of 10 yearscm per year

Countries

Australia, Austria, Canada, Denmark, France, Germany, Ireland, New Zealand, Portugal, Spain, United Kingdom, United States

Contacts

STUDY_DIRECTORMedical Director, MD

Ascendis Pharma A/S

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Aug 18, 2026