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Study on the Safety and Effectiveness of TransCon CNP for Children and Adolescents with Achondroplasia

Verified siteInvestigationalNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on studying achondroplasia, a condition that affects bone growth, leading to shorter stature in children and adolescents. The treatment being tested is called TransCon CNP, which is a special type of medication given as a solution for injection. It contains a substance known as C-type natriuretic peptide, which is linked to a carrier molecule to help it work effectively in the body. The purpose of the study is to evaluate the safety, tolerability, and effectiveness of this treatment in promoting growth over a long period.

Participants in the study will receive TransCon CNP through a subcutaneous injection, which means it is injected under the skin. This will be done once a week. The study is designed to observe how well the treatment is tolerated by the participants and to monitor any side effects that may occur. Additionally, the study aims to assess the impact of the treatment on the growth of children and adolescents with achondroplasia.

The trial will continue for an extended period to gather comprehensive data on the long-term effects of TransCon CNP. Throughout the study, various health assessments will be conducted, including physical examinations and other safety checks, to ensure the well-being of the participants. The ultimate goal is to determine if TransCon CNP can be a safe and effective option for improving growth in individuals with achondroplasia.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Consent and eligibility

    Provide written, signed consent from a parent or legal guardian. If under the age of consent, provide written assent. Upon reaching the legal age of consent, provide personal written consent.

    Ensure completion of a previous clinical trial with TransCon CNP and meet safety evaluations for eligibility.

  2. Step 2

    Weekly medication administration

    Receive a subcutaneous injection of TransCon CNP once a week. This is a solution injected under the skin.

    Parents or legal guardians must be willing and able to administer these weekly injections.

  3. Step 3

    Safety and growth assessments

    Undergo regular safety assessments, including laboratory tests, vital signs checks, physical examinations, ECG (a test that records the heart's electrical activity), and radiographic assessments.

    Monitor growth through height measurements and calculate height Z-scores throughout the trial.

  4. Step 4

    Monitoring and analysis

    Measure annual growth velocity (AGV) in centimeters per year and assess height at the end of treatment.

    Analyze plasma concentrations of total CNP, free CNP, and mPEG (a component of the medication).

    Detect and analyze anti-drug antibodies (ADA) to evaluate the body's response to the medication.

  5. Step 5

    Trial completion

    The trial is expected to continue until March 1, 2039, with ongoing assessments and monitoring throughout the duration.

Who can join the trial?

4 criteria

  • Written, signed informed consent from the parent(s) or legal guardian(s) of the participant. If the participant is old enough, they will also need to agree in writing. Once the participant reaches the legal age of consent, they will need to provide their own written consent.
  • Participants must have achondroplasia and have completed a previous clinical trial with TransCon CNP.
  • Parent(s) or legal guardian(s) must be willing and able to give weekly injections under the skin (called subcutaneous injections) of TransCon CNP and follow the study rules.
  • Participants must be considered eligible based on safety checks done during the previous TransCon CNP clinical trial.

Who cannot join the trial?

10 criteria

  • Patients who have a medical condition other than Achondroplasia that could interfere with the study.
  • Patients who have had a serious allergic reaction to any of the ingredients in the study medication.
  • Patients who are currently participating in another clinical trial.
  • Patients who have a history of significant heart problems.
  • Patients who have uncontrolled high blood pressure.
  • Patients who have a history of cancer.
  • Patients who have a history of liver or kidney disease.
  • Patients who are pregnant or breastfeeding.
  • Patients who have a history of drug or alcohol abuse.
  • Patients who are unable to comply with the study procedures.
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Investigated drugs

TransCon CNP is a medication being tested in this clinical trial. It is designed to help children and adolescents with a condition called achondroplasia, which affects bone growth and can lead to shorter stature. The medication is given as an injection under the skin once a week. The goal of using TransCon CNP is to see if it can safely and effectively help improve growth in those with achondroplasia over a long period. The trial is focused on understanding how well the medication works and how well it is tolerated by the patients who use it.

What is already known about the treatment

TransCon CNP – TransCon CNP is administered as a subcutaneous injection, meaning it is given under the skin, once a week. It is currently being studied in clinical trials for its safety, tolerability, and effectiveness in promoting growth in children and adolescents with achondroplasia, a condition that affects bone growth. The medication works by releasing a molecule called C-type natriuretic peptide (CNP) in a controlled manner, which helps regulate bone growth at the molecular level. TransCon CNP is classified as a growth regulator in pharmacology.

Investigated diseases

Achondroplasia – Achondroplasia is a genetic disorder that affects bone growth, leading to dwarfism. It is characterized by an average-sized trunk, short arms and legs, and a larger head with a prominent forehead. The condition is caused by a mutation in the FGFR3 gene, which affects the conversion of cartilage to bone, particularly in the long bones. As children with achondroplasia grow, they may experience delayed motor development and may have difficulty with certain physical activities. The progression of the disease involves disproportionate growth, which can lead to complications such as spinal stenosis and ear infections. Despite these challenges, individuals with achondroplasia typically have normal intelligence and life expectancy.
Trial detailsLast updated 7 Oct 2026
Age0-17PhasePhase IITrial ID2022-502202-33-00Protocol codeASND0039Estimated enrolment208 patientsSponsorAscendis Pharma Growth Disorders A/S

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