A Phase 2/3 interventional study of BMN 333 and Vosoritide Injection [Voxzogo] in Achondroplasia, sponsored by BioMarin Pharmaceutical. Recruiting at 28 sites in 9 countries. Open to participants aged 2 Years to 17 Years. Per ClinicalTrials.gov, last updated 2026-10-22.
Sponsored by BioMarin Pharmaceutical · Phase 2/3, Interventional, and Treatment
This is a multicenter, multinational, randomized, active-controlled, operationally seamless Phase 2/3 study of BMN 333 in treatment-naïve pediatric participants with achondroplasia (ACH). The study consists of a Phase 2 part and a Phase 3 part.
The main purpose of this study is to evaluate the effects of BMN 333 on growth compared with vosoritide in participants with achondroplasia who have not received any growth-promoting treatments. The study includes 2 parts: the Phase 2 part will select the optimal BMN 333 dose to be used in Phase 3 and determine study continuation into Phase 3; the Phase 3 part will compare the effects of the selected dose of BMN 333 with vosoritide. Study details for either Phase 2 or Phase 3 include the following:
47 studies on the registry are indexed under Achondroplasia; 13 are open to participants now.
This study's planned enrollment of 160 is above the median of 74 across 28 interventional studies indexed under Achondroplasia.
Browse Achondroplasia studies →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.
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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.
Exclusion Criteria:
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.
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.
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
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.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Autoimmune disease
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hemoglobin (Hb)
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
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.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants will be randomized to receive different dose levels of BMN 333
Drug: BMN 333
Participants will be randomized to receive different dose levels of BMN 333
Drug: BMN 333
Participants will be randomized to receive different dose levels of BMN 333
Drug: BMN 333
weight band dosing, Modified recombinant human C-type natriuretic peptide Vosoritide
Drug: Vosoritide Injection [Voxzogo]
Drug: BMN 333
weight band dosing, Modified recombinant human C-type natriuretic peptide Vosoritide
Drug: Vosoritide Injection [Voxzogo]
Administration: Weekly subcutaneous injection
Administration: Daily subcutaneous injection
Phase 2: Predicted Annualized Growth Velocity (AGV) at Week 52 (based on AGV at Weeks 26, 39, and 52 [available cumulative data]
Time frame: 52 weeks
Phase 3: Annualized Growth Velocity (AGV) at Week 52
Time frame: 52 weeks
Phase 2: AGV at Weeks 26 and 52
Time frame: 26 and 52 weeks
Phase 2: Change from Baseline in standing height
Measured in centimeters
Time frame: 26 and 52 weeks
Phase 2: Change from Baseline in height Z-score
Time frame: 26 and 52 weeks
Phase 2: Change from Baseline in upper to lower body segment ratio
Time frame: 26 and 52 weeks
Phase 2: Incidence of adverse events (AEs)
Time frame: 52 weeks
Phase 2: Incidence of serious adverse events (SAEs)
Time frame: 52 weeks
Phase 2: Incidence of events of interest (EOIs)
Time frame: 52 weeks
Phase 2: Maximum concentration (Cmax) of BMN 333 in plasma
Time frame: 52 weeks
Phase 2: Maximum concentration (Cmax) of released vosoritide in plasma
Time frame: 52 weeks
Phase 2: Time to reach maximum concentration (Tmax) for BMN 333
Time frame: 52 weeks
Phase 2: Time to reach maximum concentration (Tmax) for released vosoritide
Time frame: 52 weeks
Phase 2: Lowest concentration (C trough) of BMN 333 in plasma
Time frame: 52 weeks
Phase 2: Lowest concentration (C trough) of released vosoritide in plasma
Time frame: 52 weeks
Phase 3: Change from Baseline in standing height
Measured in centimeters
Time frame: 52 weeks
Phase 3: Change from Baseline in height Z-score
Time frame: 52 weeks
Phase 3: Change from Baseline in upper to lower body segment ratio
Time frame: 52 weeks
Plan to share: Yes — The de-identified individual participant data that underlie reported results (including text, tables, figures, and appendices) will be made available together with the research protocol and data dictionaries, for non-commercial, academic purposes. Additional supporting documents may be available upon request. Investigators will be able to request access to these data and supporting documents via a data sharing portal beginning 6 months and ending 2 years after publication. Data associated with any ongoing development program will be made available within six (6) months after approval of relevant product. Requests must include a research proposal clarifying how the data will be used, including proposed analysis methodology. Research proposals will be evaluated relative to publicly available criteria available at www.BioMarin.com/patients/publication-data-request/ to determine if access will be given, contingent upon execution of a data access agreement with BioMarin.
No publications or documents are linked to this record.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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