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Active, not recruitingNCT03989947Updated Mar 13, 2026

An Extension Study to Evaluate Safety and Efficacy of BMN 111 in Children With Achondroplasia

A Phase 2 interventional study of Active BMN 111: Subcutaneous injection of recommended dose of BMN 111 based on weight-band dosing once daily. in Achondroplasia, sponsored by BioMarin Pharmaceutical. Active, not recruiting at 16 sites in 4 countries. Open to participants aged 15 Months and older. Per ClinicalTrials.gov, last updated 2026-03-13.

Sponsored by BioMarin Pharmaceutical · Phase 2, Interventional, and Treatment

Phase
Phase 2
Study type
Interventional
Enrollment
73
Allocation
Not applicable
Ages
15 Months and older
Sex
All
01

Study summary

This is a Phase 2, open-label multi-center long-term extension study, with approximately 70 subjects, to evaluate the safety and efficacy of BMN111 in children with Achondroplasia until subjects reach near-adult final height. Eligible subjects will have completed 1 year of BMN111 or placebo treatment in the 111-206 study and once enrolled in the 111-208 extension study will receive a daily dose of BMN111 by subcutaneous injection according to their age as determined by 111-206.

02

Conditions studied

  • Achondroplasia

Keywords

  • Dwarfism
  • Bone Disease
  • ACH
  • Natriuretic Peptide C-Type
  • Musculoskeletal Diseases
  • Skeletal Dysplasias
03

In context

Achondroplasia

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

This study's enrollment of 73 is close to the median of 74 across 28 interventional studies indexed under Achondroplasia.

Browse Achondroplasia studies →

Lead sponsor

BioMarin Pharmaceutical is the lead sponsor of 112 studies on the registry; 13 are open to participants now.

Of its 17 completed or terminated interventional studies of FDA-regulated products, 12 (71%) have results posted.

Browse BioMarin Pharmaceutical studies →

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

04

Who can participate

Ages eligible
15 Months and older
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. Must have completed Study 111-206 on treatment (BMN 111 or placebo).
  2. Parent(s) or guardian(s) are willing and able to provide written, signed after the nature of the study has been explained and prior to performance of any research related procedure. Also, subjects under the age of majority are willing and able to provide written assent (if required by local regulations or the IRB/IEC) after the nature of the study has been explained and prior to performance of any research-related procedure. Subjects who reach the age of majority in their country while the study is ongoing will be asked to provide their own written consent again upon reaching the legal age of majority.
  3. Are willing and able to perform all study procedures

Exclusion criteria

Exclusion Criteria:

  1. Permanently discontinued BMN 111 or placebo prior to completion of Study 111-206
  2. Have a finding or arrhythmia on that indicates abnormal cardiac function or conduction or -F > 450 msec
  3. Require any agent (except BMN 111) prior to completion of study period
  4. Current therapy with antihypertensive medications, angiotensin-converting enzyme (ACE) inhibitors, angiotensin II receptor blockers, diuretics, beta-blockers, calcium-channel blockers, cardiac glycosides, systemic anticholinergic agents, GnRH agonists, any medication that may impair or enhance compensatory tachycardia, diuretics, or other drugs known to alter renal or tubular function
  5. Pregnant or planning to become pregnant (self or partner) at any time during the study
  6. Concurrent disease or condition that, in the view of the investigator, would interfere with study participation or safety evaluations, for any reason
  7. Have a condition or circumstance that, in the view of the investigator, places the subject at high risk for poor treatment compliance
Terms in these criteria, in plain language(5)

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.

Investigational drug or device

A drug or device being studied in a clinical trial.

It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.

Informed consent

Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.

You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.

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.

ECG (electrocardiogram)

A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.

QT and QTc

On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.

The study may name a correction formula and a limit in milliseconds, often around 450–480.

05

Study design

Phase
Phase 2
Primary purpose
Treatment
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrollment
73 participants (actual)

Study arms

  • Experimental
    Active BMN 111

    Once daily subcutaneous injections of recommended dose of BMN 111 based on weight-band dosing.

    Drug: Active BMN 111: Subcutaneous injection of recommended dose of BMN 111 based on weight-band dosing once daily.

Interventions

06

What researchers measure

Primary outcomes

  1. Evaluate the incidence of Treatment-Emergent Adverse Events [Safety and Tolerability]

    Number of study participants with treatment-emergent adverse events or serious adverse events

    Time frame: "Through study completion, an average of 5 years"

  2. Evaluate change in height/length z-score in children with ACH treated with BMN 111

    Time frame: "Through study completion, an average of 5 years"

Secondary outcomes

  1. Evaluate the change from baseline of mean annualized growth velocity (AGV)

    Time frame: "Through study completion, an average of 5 years"

  2. Characterize maximum concentration (Cmax) of BMN 111 in plasma

    Time frame: "Through study completion, an average of 5 years"

  3. Characterize the area under the plasma concentration time-curve from time 0 to infinity (AUC0-∞)

    Time frame: "Through study completion, an average of 5 years"

  4. Characterize the elimination half-life of BMN 111 (t½)

    Time frame: "Through study completion, an average of 5 years"

  5. Characterize the apparent clearance of drug

    Time frame: "Through study completion, an average of 5 years"

  6. Characterize the apparent volume of distribution based upon the terminal phase (Vz/F)

    Time frame: "Through study completion, an average of 5 years"

  7. Characterize the amount of time BMN 111 is present at maximum concentration (Tmax)

    Time frame: "Through study completion, an average of 5 years"

  8. Evaluate the change from baseline on body proportion ratios of the extremities

    Time frame: "Through study completion, an average of 5 years"

  9. Effect of BMN 111 on bone morphology and quality by XRay

    Time frame: "Through study completion, an average of 5 years"

  10. The effect of BMN 111 on bone morphology/quality will be assessed by measuring bone mineral density via Dual X-ray Absorptiometry

    Time frame: "Through study completion, an average of 5 years"

  11. Potential Changes in health-related quality of life as measured by the quality of life in Short- statured youth

    Evaluate the long-term effect of BMN 111 on health-related quality of life, developmental status and functional independence, using age-specific QoL and functional independence questionnaires (Bayley-III, WeeFIM, ITQOL, QoLISSY, PedsQL, Child Behavior Checklist 1.5-5 \[CBCL 1.5-5\], Child Behavior Checklist 6-18 \[CBCL 6-18\]).

    Time frame: "Through study completion, an average of 5 years"

  12. BMN 111 activity will be assessed by measuring bone and collagen metabolism

    Time frame: "Through study completion, an average of 5 years"

  13. Describe the incidence of surgical and medical interventions related to achondroplasia

    Time frame: "Through study completion, an average of 5 years"

  14. Assess effect on sleep disordered breathing by polysomnography in patients up to 5 years old.

    Time frame: "Through study completion, an average of 1 year"

  15. Evaluate the effect of BMN 111 on skull and brain morphology, including foramen magnum, ventricular and brain parenchymal dimensions by MRI in patients up to 3 years old.

    Time frame: "Through study completion, an average of 1 year"

07

Study locations

16 sites
08

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Mar 13, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
09

Registry details

Key details

Study ID
NCT03989947
Lead sponsor
BioMarin Pharmaceutical
Responsible party
Sponsor
First posted
Jun 18, 2019
Start date
Jun 12, 2019
Primary completion
May 2038 (estimated)
Completion
May 2038 (estimated)
Last update
Mar 13, 2026

Study contacts

Medical Director MD
study director · BioMarin Pharmaceutical

Oversight

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

Not currently enrolling

This study is active, not recruiting, as verified in Mar 2026. You cannot join it, but the record below documents what was studied.

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