AchondroplasiaPhase 3cAtCHNCT07924059
Phase 3 Clinical Trial Evaluating the Efficacy and Safety of Navepegritide and Lonapegsomatropin in Achondroplasia
A Phase 3 study testing Dual therapy with navepegritide and lonapegsomatropin in people with Achondroplasia, run by Ascendis Pharma A/S.
Trial summary
This pivotal trial is being conducted to evaluate the efficacy, safety and tolerability of dual therapy with navepegritide and lonapegsomatropin administered as separate subcutaneous (SC) injections once weekly in children with achondroplasia (ACH) aged 2 to 17 years. Read more about this study
- Who is it for?
- Ages 2 to 17 years
- Conditions the study is for
- Achondroplasia
- What is being tested?
- Dual therapy with navepegritide and lonapegsomatropin
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 144 participants
- Where
- No sites listed yet
- Study dates
- Nov 2026to Sep 2029
- Phase
- Phase 3
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 2 to 17 years
- All sexes
- No healthy volunteers
- Child
Who may be able to join
- 1. Age 2 to <18 years at randomization
- 2. Clinical diagnosis of ACH with historical genetic confirmation
- 3. At least 1 height measurement available from medical records
Who cannot join
- 1. Treatment with growth hormone within 1 year prior to randomization
- 2. Prior treatment with certain medication(s) which potentially could have affected growth (prior treatment with vosoritide is not exclusive)
- 3. History of any surgery intended to affect stature, growth, or body proportionality except procedures for leg bowing
- 4. Unable to stand without assistance
- 5. Known or suspected medical conditions other than achondroplasia that could affect growth
- 6. Known history or presence of injury of the growth plates that affects growth potential of long bones
- 7. Known history or presence of malignant disease
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
About this study
Official title: A Phase 3, Randomized, Double-blind, Active Controlled, Multi-center Trial Investigating the Efficacy and Safety of Dual Therapy With Once-weekly Navepegritide and Once-weekly Lonapegsomatropin Compared to Navepegritide Monotherapy and Lonapegsomatropin Monotherapy in Children and Adolescents With Achondroplasia
This pivotal trial is being conducted to evaluate the efficacy, safety and tolerability of dual therapy with navepegritide and lonapegsomatropin administered as separate subcutaneous (SC) injections once weekly in children with achondroplasia (ACH) aged 2 to 17 years.
- Conditions
- Achondroplasia
- Being tested
- Dual therapy with navepegritide and lonapegsomatropin, Dual therapy with navepegritide and placebo for lonapegsomatropin, Dual therapy with lonapegsomatropin and placebo for navepegritide
- Medical subject headings
- Achondroplasia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Dual therapy with navepegritide and lonapegsomatropinDrug
Administered weekly as two separate SC injections. Treatment duration of up to 104 weeks
Dual therapy with navepegritide and placebo for lonapegsomatropinDrug
Administered as two separate SC injections. Treatment duration of up to 52 weeks of navepegritide and placebo for lonapegsomatropin followed by 52 weeks of navepegritide and lonapegsomatropin.
Dual therapy with lonapegsomatropin and placebo for navepegritideDrug
Administered as two separate SC injections. Treatment duration of up to 52 weeks of lonapegsomatropin and placebo for navepegritide followed by 52 weeks of navepegritide and lonapegsomatropin.
| Study group | Role | What they receive |
|---|---|---|
| Once weekly navepegritide SC and lonapegsomatropin SC | Experimental | Not described Receives: Drug: Dual therapy with navepegritide and lonapegsomatropin |
| Once weekly navepegritide SC and placebo for lonapegsomatropin SC | Experimental | Not described Receives: Drug: Dual therapy with navepegritide and placebo for lonapegsomatropin |
| Once weekly lonapegsomatropin SC and placebo for navepegritide SC | Experimental | Not described Receives: Drug: Dual therapy with lonapegsomatropin and placebo for navepegritide |
What is being measured
The primary outcome is the main question the study is designed to answer.
Annualized Growth Velocity (AGV)
To evaluate the AGV, cm per year, of dual therapy with navepegritide and lonapegsomatropin compared to navepegritide alone
Measured: 52 weeks
Secondary outcomes (10)
Annualized Growth Velocity (AGV)
To evaluate the AGV, cm per year, of dual therapy with navepegritide and lonapegsomatropin compared to lonapegsomatroptin alone
Measured: 52 weeks
Annualized Growth Velocity (AGV) change from baseline
To evaluate the change from baseline in AGV, cm per year
Measured: 52 weeks
ACH-specific height Z-score
To evaluate the change from baseline in ACH-specific height Z-score
Measured: 52 weeks
CDC-based height Z-score
To evaluate the change from baseline in CDC-based height Z-score
Measured: 52 weeks
Treatment-emergent Adverse Events (AE)
Number of events
Measured: Throughout trial duration 104 weeks
Bone safety
Qualitative assessment with radiology
Measured: Throughout trial duration 104 weeks
Arm span Z-score
Change from baseline in arm span Z-score.
Measured: 52 weeks
Upper to lower body segment ratio
Change from baseline in upper to lower body segment ratio.
Measured: 52 weeks
Arm span
Change from baseline in arm span, cm.
Measured: 52 weeks
Interpedicular distance (IDP)
Change from baseline in IDP (L1-L4 average), mm
Measured: 52 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted9 Nov 2026
- Study startNov 2026 (estimated)
- Primary completionSep 2028 (estimated)
- Study completionSep 2029 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for AchondroplasiaStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 3
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 144 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Ascendis Pharma A/S
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Medical Director, MD, Study director, Ascendis Pharma A/S
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07924059
- Sponsor's protocol ID
- ASND0053
- Acronym
- cAtCH
- Status last verified
- Nov 2026
- First submitted
- 30 Oct 2026
- Last updated
- 9 Nov 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 9 Nov 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 3, Randomized, Double-blind, Active Controlled, Multi-center Trial Investigating the Efficacy and Safety of Dual Therapy With Once-weekly Navepegritide and Once-weekly Lonapegsomatropin Compared to Navepegritide Monotherapy and Lonapegsomatropin Monotherapy in Children and Adolescents With Achondroplasia
- ClinicalTrials.gov ID
- NCT07924059
- Acronym / sponsor ID
- cAtCH / ASND0053
- Conditions
- Achondroplasia
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 144 participants (estimated)
- Lead sponsor
- Ascendis Pharma A/SIndustry (pharma, biotech, devices)
- Study start
- Nov 2026 (estimated)
- Primary completion
- Sep 2028 (estimated)
- Study completion
- Sep 2029 (estimated)
- First posted
- 9 Nov 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This pivotal trial is being conducted to evaluate the efficacy, safety and tolerability of dual therapy with navepegritide and lonapegsomatropin administered as separate subcutaneous (SC) injections once weekly in children with achondroplasia (ACH) aged 2 to 17 years.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Once weekly navepegritide SC and lonapegsomatropin SC | Experimental | Drug: Dual therapy with navepegritide and lonapegsomatropin |
| Once weekly navepegritide SC and placebo for lonapegsomatropin SC | Experimental | Drug: Dual therapy with navepegritide and placebo for lonapegsomatropin |
| Once weekly lonapegsomatropin SC and placebo for navepegritide SC | Experimental | Drug: Dual therapy with lonapegsomatropin and placebo for navepegritide |
Who may qualify
- Ages
- 2 to 17 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child
Key inclusion criteria (3 listed)
- 1. Age 2 to <18 years at randomization
- 2. Clinical diagnosis of ACH with historical genetic confirmation
- 3. At least 1 height measurement available from medical records
Key exclusion criteria (7 listed)
- 1. Treatment with growth hormone within 1 year prior to randomization
- 2. Prior treatment with certain medication(s) which potentially could have affected growth (prior treatment with vosoritide is not exclusive)
- 3. History of any surgery intended to affect stature, growth, or body proportionality except procedures for leg bowing
- 4. Unable to stand without assistance
- 5. Known or suspected medical conditions other than achondroplasia that could affect growth
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Dual therapy with navepegritide and lonapegsomatropinAdministered weekly as two separate SC injections. Treatment duration of up to 104 weeks | Drug | Once weekly navepegritide SC and lonapegsomatropin SC |
| Dual therapy with navepegritide and placebo for lonapegsomatropinAdministered as two separate SC injections. Treatment duration of up to 52 weeks of navepegritide and placebo for lonapegsomatropin followed by 52 weeks of navepegritide and lonapegsomatropin. | Drug | Once weekly navepegritide SC and placebo for lonapegsomatropin SC |
| Dual therapy with lonapegsomatropin and placebo for navepegritideAdministered as two separate SC injections. Treatment duration of up to 52 weeks of lonapegsomatropin and placebo for navepegritide followed by 52 weeks of navepegritide and lonapegsomatropin. | Drug | Once weekly lonapegsomatropin SC and placebo for navepegritide SC |
Primary outcome
Annualized Growth Velocity (AGV)
Time frame: 52 weeks
To evaluate the AGV, cm per year, of dual therapy with navepegritide and lonapegsomatropin compared to navepegritide alone
10 secondary outcomes
Annualized Growth Velocity (AGV)
Time frame: 52 weeks
Annualized Growth Velocity (AGV) change from baseline
Time frame: 52 weeks
ACH-specific height Z-score
Time frame: 52 weeks
CDC-based height Z-score
Time frame: 52 weeks
Treatment-emergent Adverse Events (AE)
Time frame: Throughout trial duration 104 weeks
Bone safety
Time frame: Throughout trial duration 104 weeks
Arm span Z-score
Time frame: 52 weeks
Upper to lower body segment ratio
Time frame: 52 weeks
Arm span
Time frame: 52 weeks
Interpedicular distance (IDP)
Time frame: 52 weeks
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 9 Nov 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Medical Director, MD study director
Ascendis Pharma A/S
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing Dual therapy with navepegritide and lonapegsomatropin in people with Achondroplasia, run by Ascendis Pharma A/S.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 9 Nov 2026. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Ascendis Registry Inquiries (+45 61242484, asnd_registryinquiries@ascendispharma.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Annualized Growth Velocity (AGV) (time frame: 52 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 9 Nov 2026; AzTrials last refreshed its copy on 9 Nov 2026.