Study to Evaluate the Efficacy and Safety of BMN 333 Versus Vosoritide in Children With Achondroplasia
ASPEN
A Multicenter, Randomized, Operationally Seamless Phase 2/3 Study to Evaluate the Efficacy and Safety of BMN 333 Versus Vosoritide in Children With Achondroplasia
1 other identifier
interventional
160
9 countries
19
Brief Summary
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.
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
participants targeted
Target at P75+ for phase_2
Started Apr 2026
Typical duration for phase_2
19 active sites
Health score is calculated from publicly available data and should be used for screening purposes only.
Trial Relationships
Click on a node to explore related trials.
Study Timeline
Key milestones and dates
First Submitted
Initial submission to the registry
February 11, 2026
CompletedFirst Posted
Study publicly available on registry
March 2, 2026
CompletedStudy Start
First participant enrolled
April 20, 2026
CompletedPrimary Completion
Last participant's last visit for primary outcome
June 1, 2029
ExpectedStudy Completion
Last participant's last visit for all outcomes
September 1, 2029
July 24, 2026
July 1, 2026
3.1 years
February 11, 2026
July 23, 2026
Conditions
Keywords
Outcome Measures
Primary Outcomes (2)
Phase 2: Predicted Annualized Growth Velocity (AGV) at Week 52 (based on AGV at Weeks 26, 39, and 52 [available cumulative data]
52 weeks
Phase 3: Annualized Growth Velocity (AGV) at Week 52
52 weeks
Secondary Outcomes (16)
Phase 2: AGV at Weeks 26 and 52
26 and 52 weeks
Phase 2: Change from Baseline in standing height
26 and 52 weeks
Phase 2: Change from Baseline in height Z-score
26 and 52 weeks
Phase 2: Change from Baseline in upper to lower body segment ratio
26 and 52 weeks
Phase 2: Incidence of adverse events (AEs)
52 weeks
- +11 more secondary outcomes
Study Arms (6)
Phase 2: Low Dose
EXPERIMENTALParticipants will be randomized to receive different dose levels of BMN 333
Phase 2: Medium Dose
EXPERIMENTALParticipants will be randomized to receive different dose levels of BMN 333
Phase 2: High Dose
EXPERIMENTALParticipants will be randomized to receive different dose levels of BMN 333
Phase 2: Vosoritide
ACTIVE COMPARATORweight band dosing, Modified recombinant human C-type natriuretic peptide Vosoritide
Phase 3: BMN 333 at selected dose after Phase 2
EXPERIMENTALPhase 3: Vosoritide
ACTIVE COMPARATORweight band dosing, Modified recombinant human C-type natriuretic peptide Vosoritide
Interventions
Administration: Weekly subcutaneous injection
Administration: Daily subcutaneous injection
Eligibility Criteria
You may qualify if:
- Participants must be aged ≥ 2 to \< 11 years (Phase 2) or ≥ 2 to \< 18 years (Phase 3), at the time of signing the informed consent
- Participants must have ACH (confirmed by documented genetic testing) and open epiphyses
- Are Tanner Stage I (Phase 2) or any Tanner stage (Phase 3)
- Are ambulatory and able to stand without assistance
You may not qualify if:
- Have any short stature condition other than ACH (eg, hypochondroplasia, trisomy 21, pseudoachondroplasia, GH deficiency)
- Have any of the following disorders: Hypothyroidism or hyperthyroidism, unless treated with evidence of normalized thyroid-stimulating hormone (TSH) levels, diabetes mellitus, unless considered well-controlled, autoimmune inflammatory disease, inflammatory bowel disease, autonomic neuropathy, anemia defined as hemoglobin \< 10 g/dL, vitamin D deficiency, significant hip pathology.
- Have history of any renal insufficiency or cardiac/ cardiovascular disease that places the participant at increased risk of an adverse cardiac outcome in the setting of hypotension.
- Have had bone fractures of the long bones or spine within 6 months prior to screening.
- Have used vosoritide, any other approved product (except GH, as detailed below), investigational product, or investigational medical device for the treatment of ACH or short stature at any time
- Have been treated with GH, insulin-like growth factor 1, or anabolic steroids in the 6 months prior to treatment start
Contact the study team to confirm eligibility.
Sponsors & Collaborators
Study Sites (19)
UCSF Benioff Children's Hospital Oakland
Oakland, California, 94609, United States
Nemours Children's Health
Wilmington, Delaware, 19803, United States
Ann & Robert H. Lurie Children's Hospital of Chicago
Chicago, Illinois, 60611, United States
Johns Hopkins Medicine
Baltimore, Maryland, 21205, United States
Cincinnati Children's Hospital Medical Center
Cincinnati, Ohio, 45229, United States
Children's Hospital of Philadelphia
Philadelphia, Pennsylvania, 19104, United States
University of Texas Southwestern Medical Center
Dallas, Texas, 75207, United States
Texas Children Hospital, Baylor College of Medicine
Houston, Texas, 77030, United States
Consano Clinical Research, LLC
San Antonio, Texas, 78231, United States
Murdoch Children's Research Institute
Parkville, Victoria, 3052, Australia
Universite de Montreal - Centre Hospitalier Universitaire Sainte-Justine
Montreal, Quebec, H3T 1C5, Canada
Irccs Ospedale Gaslini Di Genova
Genova, 16147, Italy
Osaka City General Hospital
Osaka, 534-0021, Japan
Uniwersytecki Szpital Kliniczny im. J. Mikulicza-Radeckiego we Wroclawiu Klinika Pediatrii i Chorob Infekcyjnych
Wroclaw, Poland
Institutul National de Endocrinologie C.I.Parhon
Bucharest, Romania
Craiova Emergency Clinical County
Craiova, 200642, Romania
Seoul National University Hospital
Seoul, South Korea
Pusan National University Yangsan Hospital
Yangsan, 50612, South Korea
University Hospitals Bristol NHS Foundation Trust - Bristol Royal Hospital for Children
Bristol, United Kingdom
MeSH Terms
Conditions
Interventions
Condition Hierarchy (Ancestors)
Study Officials
- STUDY DIRECTOR
Medical Director, PhD
BioMarin Pharmaceutical
Central Study Contacts
Study Design
- Study Type
- interventional
- Phase
- phase 2
- Allocation
- RANDOMIZED
- Masking
- SINGLE
- Who Masked
- OUTCOMES ASSESSOR
- Purpose
- TREATMENT
- Intervention Model
- PARALLEL
- Sponsor Type
- INDUSTRY
- Responsible Party
- SPONSOR
Study Record Dates
First Submitted
February 11, 2026
First Posted
March 2, 2026
Study Start
April 20, 2026
Primary Completion (Estimated)
June 1, 2029
Study Completion (Estimated)
September 1, 2029
Last Updated
July 24, 2026
Record last verified: 2026-07
Data Sharing
- IPD Sharing
- Will share
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.