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CompletedNCT04085523Updated Jul 2, 2026Results posted

A Dose Escalation Trial Evaluating Safety, Efficacy, and Pharmacokinetics of TransCon CNP Administered Once Weekly in Prepubertal Children With Achondroplasia

A Phase 2 interventional study of TransCon CNP and Placebo for TransCon CNP in Achondroplasia, sponsored by Ascendis Pharma A/S. Completed at 15 sites in 8 countries. Open to participants aged 2 Years to 10 Years. Per ClinicalTrials.gov, last updated 2026-07-02.

Sponsored by Ascendis Pharma A/S · Phase 2, Interventional, and Treatment

Phase
Phase 2
Study type
Interventional
Enrollment
57
Allocation
Randomized
Ages
2 Years to 10 Years
Sex
All
01

Study summary

The trial is a multicenter, double-blind, randomized, placebo-controlled, dose escalation trial of weekly TransCon CNP administered subcutaneously in prepubertal children 2 to 10 years old, inclusive, with Achondroplasia.

02

Conditions studied

  • Achondroplasia

Keywords

  • Achondroplasia
  • Dwarfism
03

In context

Achondroplasia

47 studies on the registry are indexed under Achondroplasia; 13 are open to participants now.

This study's enrollment of 57 is below the median of 74 across 28 interventional studies indexed under Achondroplasia.

Browse Achondroplasia studies →

Lead sponsor

Ascendis Pharma A/S is the lead sponsor of 17 studies on the registry; 7 are open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
2 Years to 10 Years
Sexes eligible
All
Accepts healthy volunteers
No

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  1. Clinical diagnosis of ACH with genetic confirmation
  2. Age between 2 to 10 years old (inclusive) at Screening Visit
  3. Prepubertal (Stage 1 breasts for girls or testicular volume \< 4ml for boys) at Screening Visit
  4. Able to stand without assistance
  5. Caregiver willing and able to administer subcutaneous injections of study drug

Exclusion criteria

Exclusion Criteria:

  1. findings at Screening that:

    • are expected to require surgical intervention during participation in the trial or
    • are musculoskeletal in nature, such as Salter-Harris fractures and severe hip pain or
    • otherwise are considered by investigator or Medical Monitor/Medical Expert to make a participant unfit to receive study drug or undergo trial related procedures
  2. Have received treatment (>3 months) of human growth hormone (hGH) or other medications known to affect stature or body proportionality at any time
  3. Have received any dose of medications intended to affect stature or body proportionality within the previous 6 months of Screening Visit
  4. Have received any study drug or device intended to affect stature or body proportionality at any time
  5. History or presence of injury or disease of the growth plate(s), other than Achondroplasia, that affects growth potential of long bones
Terms in these criteria, in plain language(1)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

Clinically significant

Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.

05

Study design

Phase
Phase 2
Primary purpose
Treatment
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Quadruple (Participant, Care provider, Investigator, Outcomes assessor)
Enrollment
57 participants (actual)

Study arms

  • Experimental
    TransCon CNP 6 mcg

    TransCon CNP 6 mcg CNP/kg delivered once weekly by subcutaneous injection.

    Drug: TransCon CNP

  • Experimental
    TransCon CNP 20 mcg

    TransCon CNP 20 mcg CNP/kg delivered once weekly by subcutaneous injection.

    Drug: TransCon CNP

  • Experimental
    TransCon CNP 50 mcg

    TransCon CNP 50 mcg CNP/kg delivered once weekly by subcutaneous injection.

    Drug: TransCon CNP

  • Experimental
    TransCon CNP 100 mcg

    TransCon CNP 100 mcg CNP/kg delivered once weekly by subcutaneous injection.

    Drug: TransCon CNP

  • Placebo comparator
    Placebo

    Placebo mimicking 6, 20, 50, or 100 mcg CNP/kg delivered once weekly by subcutaneous injection.

    Drug: Placebo for TransCon CNP

  • Experimental
    Open-Label Extension Period: TransCon CNP

    Participants who completed the 52-week blinded treatment period continued into the 104-week open-label extension period and received treatment with TransCon CNP (navepegritide) doses escalated up to a maximum of 100 mcg/kg delivered once weekly by subcutaneous injection.

    Drug: TransCon CNP

Interventions

  • DrugTransCon CNP

    TransCon CNP drug product is a lyophilized powder in a single-use vial containing either TransCon CNP 3.9 mg CNP-38/vial or TransCon CNP 0.80 mg CNP-38/vial. Prior to use, the lyophilized powder is reconstituted with sterile water for injection and administered by subcutaneous injection via syringe and needle.

  • DrugPlacebo for TransCon CNP

    Weekly subcutaneously injection of placebo.

06

What researchers measure

Primary outcomes

  1. Annualized Height Velocity (cm/Year) After 52 Weeks of Double-blind Treatment

    The primary efficacy analysis compared the difference in the primary efficacy endpoint between the TransCon CNP treatment group and the pooled placebo group using an ANCOVA model with the annualized height velocity (AHV) at Week 52 as the response variable, treatment (dose groups and placebo) and sex as factors, baseline age and baseline height SDS as the covariates, and based on the Full Analysis Set.

    Time frame: 52 weeks

07

Results

Posted Mar 7, 2024

Participant flow

Double-Blind Period (Weeks 0 to 52)
Participant flow — Double-Blind Period (Weeks 0 to 52)
MilestoneTransCon CNP 6 mcgTransCon CNP 20 mcgTransCon CNP 50 mcgTransCon CNP 100 mcgPlaceboOpen-Label Extension Period: TransCon CNP
Started10111011150
Completed10111011150
Not completed000000
Open-Label Period (Weeks 52 to 156)
Participant flow — Open-Label Period (Weeks 52 to 156)
MilestoneTransCon CNP 6 mcgTransCon CNP 20 mcgTransCon CNP 50 mcgTransCon CNP 100 mcgPlaceboOpen-Label Extension Period: TransCon CNP
Started0000057
Completed0000055
Not completed000002
Withdrew: Withdrawal by subject000002

Outcome measures

PrimaryAnnualized Height Velocity (cm/Year) After 52 Weeks of Double-blind Treatment

The primary efficacy analysis compared the difference in the primary efficacy endpoint between the TransCon CNP treatment group and the pooled placebo group using an ANCOVA model with the annualized height velocity (AHV) at Week 52 as the response variable, treatment (dose groups and placebo) and sex as factors, baseline age and baseline height SDS as the covariates, and based on the Full Analysis Set.

Time frame:
52 weeks
Reported as:
Least squares mean · cm/year
Annualized Height Velocity (cm/Year) After 52 Weeks of Double-blind Treatment
cm/yearTransCon CNP 6 mcgTransCon CNP 20 mcgTransCon CNP 50 mcgTransCon CNP 100 mcgPlacebo
Annualized Height Velocity (cm/Year) After 52 Weeks of Double-blind Treatment4.09 (3.34 to 4.84)4.52 (3.82 to 5.22)5.16 (4.43 to 5.90)5.42 (4.74 to 6.11)4.35 (3.75 to 4.94)
Statistical analysis
  • TransCon CNP 6 mcg vs Placebo · ANCOVA · p = = 0.6004
  • TransCon CNP 20 mcg vs Placebo · ANCOVA · p = = 0.7022
  • TransCon CNP 50 mcg vs Placebo · ANCOVA · p = = 0.0849
  • TransCon CNP 100 mcg vs Placebo · ANCOVA · p = = 0.0218

Adverse events

Collected over From Week 0 to Week 52 for double-blind treatment period and up to Week 156 for OLE Period. Non-serious events are listed at a 5% frequency threshold.

Adverse event summary by group
GroupDeathsSeriousOther
TransCon CNP 6 mcg0/10 (0%)1/10 (10%)9/10 (90%)
TransCon CNP 20 mcg0/11 (0%)0/11 (0%)11/11 (100%)
TransCon CNP 50 mcg0/10 (0%)1/10 (10%)10/10 (100%)
TransCon CNP 100 mcg0/11 (0%)0/11 (0%)10/11 (90.9%)
Placebo0/15 (0%)0/15 (0%)14/15 (93.3%)
Open-Label Extension Period: TransCon CNP0/57 (0%)2/57 (3.5%)57/57 (100%)
Most frequent serious events
Most frequent serious events
EventTransCon CNP 6 mcgTransCon CNP 20 mcgTransCon CNP 50 mcgTransCon CNP 100 mcgPlaceboOpen-Label Extension Period: TransCon CNP
Febrile ConvulsionNervous system disorders0/100/111/100/110/150/57
Viral infectionInfections and infestations1/100/110/100/110/150/57
InfluenzaInfections and infestations1/100/110/100/110/151/57
Obstructive sleep apnoea syndromeRespiratory, thoracic and mediastinal disorders0/100/110/100/110/151/57
Tonsillar hypertrophyRespiratory, thoracic and mediastinal disorders0/100/110/100/110/151/57
Most frequent other events
Showing 10 of 52
Most frequent other events
EventTransCon CNP 6 mcgTransCon CNP 20 mcgTransCon CNP 50 mcgTransCon CNP 100 mcgPlaceboOpen-Label Extension Period: TransCon CNP
Upper respiratory tract infectionInfections and infestations3/101/115/100/112/1514/57
NasopharyngitisInfections and infestations1/100/115/102/111/1520/57
PyrexiaGeneral disorders1/104/112/102/115/1523/57
CoughRespiratory, thoracic and mediastinal disorders4/103/114/102/113/1521/57
COVID-19Infections and infestations0/101/111/103/111/1520/57
HeadacheNervous system disorders0/101/113/102/112/1517/57
Pain in extremityMusculoskeletal and connective tissue disorders1/101/113/103/111/157/57
ArthralgiaMusculoskeletal and connective tissue disorders1/100/113/101/111/159/57
GastroenteritisInfections and infestations0/102/113/101/112/1510/57
Respiratory tract infectionInfections and infestations0/100/113/100/110/150/57

Baseline characteristics

Age, Continuous
Age, Continuous(years)TransCon CNP 6 mcgTransCon CNP 20 mcgTransCon CNP 50 mcgTransCon CNP 100 mcgPlaceboTotal
Mean6.52 ± 2.5936.29 ± 2.8965.20 ± 2.9915.79 ± 2.6135.89 ± 3.1095.94 ± 2.800
Sex: Female, Male
Sex: Female, Male(Participants)TransCon CNP 6 mcgTransCon CNP 20 mcgTransCon CNP 50 mcgTransCon CNP 100 mcgPlaceboTotal
Female7336524
Male38751033
Ethnicity (NIH/OMB)
Ethnicity (NIH/OMB)(Participants)TransCon CNP 6 mcgTransCon CNP 20 mcgTransCon CNP 50 mcgTransCon CNP 100 mcgPlaceboTotal
Hispanic or Latino102216
Not Hispanic or Latino911691449
Unknown or Not Reported002002
Race (NIH/OMB)
Race (NIH/OMB)(Participants)TransCon CNP 6 mcgTransCon CNP 20 mcgTransCon CNP 50 mcgTransCon CNP 100 mcgPlaceboTotal
American Indian or Alaska Native000000
Asian211026
Native Hawaiian or Other Pacific Islander001001
Black or African American000112
White8108101248
More than one race000000
Unknown or Not Reported000000
Height
Height(cm)TransCon CNP 6 mcgTransCon CNP 20 mcgTransCon CNP 50 mcgTransCon CNP 100 mcgPlaceboTotal
Mean90.63 ± 8.97392.29 ± 12.10386.61 ± 12.96789.23 ± 12.82290.85 ± 14.92090.03 ± 12.434
Height SDS
Height SDS(standard deviation score)TransCon CNP 6 mcgTransCon CNP 20 mcgTransCon CNP 50 mcgTransCon CNP 100 mcgPlaceboTotal
Mean-5.45 ± 1.046-4.87 ± 0.673-4.85 ± 0.801-4.92 ± 0.829-4.85 ± 0.958-4.97 ± 0.873
Weight
Weight(kg)TransCon CNP 6 mcgTransCon CNP 20 mcgTransCon CNP 50 mcgTransCon CNP 100 mcgPlaceboTotal
Mean17.49 ± 3.67719.67 ± 6.60215.67 ± 4.39917.03 ± 4.69917.99 ± 5.54217.64 ± 5.129
Body Mass Index (BMI)
Body Mass Index (BMI)(kg/m^2)TransCon CNP 6 mcgTransCon CNP 20 mcgTransCon CNP 50 mcgTransCon CNP 100 mcgPlaceboTotal
Mean21.10 ± 1.66422.52 ± 2.59920.61 ± 1.49621.11 ± 1.61221.39 ± 1.85321.36 ± 1.930
08

Study locations

15 sites
  • Ascendis Pharma Investigational Site
    Little Rock, Arkansas 72211, United States
  • Ascendis Pharma Investigational Site
    Aurora, Colorado 80045, United States
  • Ascendis Pharma Investigational Site
    Saint Paul, Minnesota 55102, United States
  • Ascendis Pharma Investigational Site
    Columbia, Missouri 65212, United States
  • Ascendis Pharma Investigational Site
    Buffalo, New York 14203, United States
  • Ascendis Pharma Investigational Site
    Houston, Texas 77030, United States
  • Ascendis Pharma Investigational Site
    Seattle, Washington 98105, United States
  • Ascendis Pharma Investigational Site
    Madison, Wisconsin 53705, United States
  • Ascendis Pharma Investigational Site
    Parkville, Victoria 3052, Australia
  • Ascendis Pharma Investigational Site
    Linz, 4020, Austria
  • Ascendis Pharma Investigational Site
    Copenhagen, 2100, Denmark
  • Ascendis Pharma Investigational Site
    Berlin, 13353, Germany
  • Ascendis Pharma Investigational Site
    Dublin, D01 YC76, Ireland
  • Ascendis Pharma Investigational Site
    Auckland, 1023, New Zealand
  • Ascendis Pharma Investigational Site
    Coimbra, 3000-602, Portugal
09

References and documents

Publications

  • Savarirayan R, Hoernschemeyer DG, Ljungberg M, Zarate YA, Bacino CA, Bober MB, Legare JM, Hogler W, Quattrin T, Abuzzahab MJ, Hofman PL, White KK, Ma NS, Schnabel D, Sousa SB, Mao M, Smith A, Chakraborty M, Giwa A, Winding B, Volck B, Shu AD, McDonnell C. Once-weekly TransCon CNP (navepegritide) in children with achondroplasia (ACcomplisH): a phase 2, multicentre, randomised, double-blind, placebo-controlled, dose-escalation trial. EClinicalMedicine. 2023 Oct 2;65:102258. doi: 10.1016/j.eclinm.2023.102258. eCollection 2023 Nov. PubMed 37823031 ↗
  • Brod M, McLeod L, Smith A. Assessing signs and impacts of achondroplasia: psychometric evaluation of the Achondroplasia Child Experience Measures. J Patient Rep Outcomes. 2026 Jun 19. doi: 10.1186/s41687-026-01123-z. Online ahead of print. PubMed 42319555 ↗

Study documents

PDFs hosted by the registry, ClinicalTrials.gov.

10

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Jul 2, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
11

Registry details

Key details

Study ID
NCT04085523
Lead sponsor
Ascendis Pharma A/S
Responsible party
Sponsor
First posted
Sep 11, 2019
Start date
Jun 24, 2020
Primary completion
Sep 27, 2022
Completion
Oct 1, 2024
Results posted
Mar 7, 2024
Last update
Jul 2, 2026

Study contacts

Study Director, MD
study director · Ascendis Pharma, Inc.

Oversight

Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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