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

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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 genetic condition that affects bone growth, leading to shorter stature and other physical differences. The trial will evaluate a treatment called TransCon CNP, which is a solution for injection. This treatment involves a special type of protein called C-type natriuretic peptide that is linked to a carrier molecule to help it work effectively in the body. The study will compare the effects of TransCon CNP with a placebo, which is a substance with no active medication, to understand its safety, tolerability, and impact on growth in infants with achondroplasia.

The purpose of the study is to assess how safe and well-tolerated TransCon CNP is, as well as its effect on growth in young children with achondroplasia. Participants in the study will receive weekly injections of either TransCon CNP or a placebo for a period of 52 weeks. After this period, there will be an open-label extension, where all participants may receive the actual medication. The study aims to observe any side effects and measure changes in growth over time.

Throughout the study, various assessments will be conducted to monitor the health and development of the participants. These assessments will include measuring growth rates and evaluating any potential side effects. The study will also use imaging techniques like MRI to examine changes in bone structure and other physical characteristics associated with achondroplasia. The goal is to gather comprehensive data on how TransCon CNP affects growth and overall health in children with this condition.

The research process

The trial runs in 4 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial treatment phase

    The trial begins with the administration of the investigational medication, TransCon CNP, or a placebo. This is done through a subcutaneous injection, which means the medication is injected under the skin.

    The injections are given once a week for a period of 52 weeks. This phase is designed to evaluate the safety and effectiveness of the treatment in infants with achondroplasia.

  2. Step 2

    Monitoring and assessment

    Throughout the 52-week period, regular monitoring is conducted to assess the participant's response to the treatment. This includes measuring growth and observing any side effects.

    The primary focus is on the occurrence of any adverse events and changes in growth patterns, specifically the length/height Z-score, which is a standardized measure of growth.

  3. Step 3

    Open label extension period

    After the initial 52 weeks, participants may enter an open label extension period. During this phase, all participants receive the TransCon CNP treatment, regardless of whether they initially received the placebo.

    This phase allows for continued monitoring of growth and development over an extended period, up to 104 weeks in total.

  4. Step 4

    Additional evaluations

    Additional assessments are conducted to evaluate various aspects of development, including motor and language skills, as well as imaging studies such as X-rays and MRIs to examine bone growth and spinal development.

    These evaluations help to provide a comprehensive understanding of the treatment's impact on the participant's overall health and development.

Who can join the trial?

7 criteria

  • The parent(s) or caregiver(s) must provide written and signed consent for the child to participate in the study.
  • The child must be younger than 2 years old at the time of joining the study.
  • The child must have a clinical diagnosis of achondroplasia, which is a condition affecting bone growth, confirmed by a genetic test.
  • The parent(s) or caregiver(s) must be willing to follow the study's instructions, including giving weekly injections under the skin as part of the treatment.
  • For infants aged 14 days to 1 year, they must take daily Vitamin D supplements. Children older than 1 year with low Vitamin D levels must start taking daily Vitamin D supplements before joining the study.
  • The child must be considered eligible based on their medical history, physical examination, and results from tests like heart monitoring (ECG), imaging, and lab tests done during the screening period.
  • The child must not be eligible for treatment with vosoritide, a medication for achondroplasia, for reasons such as it not being available in their country, the parent(s) or caregiver(s) not wanting to start this treatment, or not being able to afford it if not fully covered by insurance.

Who cannot join the trial?

7 criteria

  • Children and adolescents who do not have Achondroplasia, a condition affecting bone growth, cannot participate.
  • Participants who are not within the specified age range for the study cannot join.
  • Individuals who have other medical conditions that might interfere with the study cannot take part.
  • Participants who are currently taking medications that could affect the study results are not eligible.
  • Children and adolescents who have participated in another clinical trial recently may be excluded.
  • Individuals who have a history of allergic reactions to similar treatments cannot participate.
  • Participants who are unable to comply with the study procedures and visits are not eligible.
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Investigated drugs

TransCon CNP is a medication being studied for its potential to help infants with achondroplasia, a condition that affects bone growth. This medication is given as an injection under the skin once a week. The trial aims to see if TransCon CNP is safe and well-tolerated by the infants and to observe its effects on their growth over a period of 52 weeks.

What is already known about the treatment

TransCon CNP – This medication is administered through subcutaneous injections, typically given once a week. It is currently being studied in clinical trials, specifically in a Phase 2 trial, to assess its safety, tolerability, and effectiveness in promoting growth in infants with achondroplasia. The main therapeutic indication for TransCon CNP is to address growth deficiencies associated with achondroplasia in children and adolescents. At the molecular level, it works by releasing C-type natriuretic peptide (CNP) in a controlled manner, which helps regulate bone growth. Pharmacologically, it is classified as a growth modulator.

Investigated diseases

Achondroplasia – Achondroplasia is a genetic disorder that affects bone growth, leading to dwarfism. It is characterized by short stature with disproportionately short arms and legs, a large head, and distinctive facial features. 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 challenges with balance and coordination. Other common features include a prominent forehead, a flattened bridge of the nose, and spinal curvature. Despite these physical characteristics, individuals with achondroplasia typically have normal intelligence and life expectancy.
Trial detailsLast updated 7 Oct 2026
Age0-17PhasePhase IITrial ID2023-506091-27-00Protocol codeASND0030Estimated enrolment86 patientsSponsorAscendis Pharma Growth Disorders A/S

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