Study to Evaluate the Efficacy and Safety of BMN 333 Versus Vosoritide in Children With Achondroplasia

Short name ASPEN

NCTNCT07441876Other id333-301

Open at ClinicalTrials.govAsk about this trial

Overview

Status: Recruiting
Phase: Phase 2/3
Enrollment: 160 participants (estimated)
Sponsor: BioMarin Pharmaceutical · Industry
Design: Randomized · Single masking
Countries: 9 countries
United States, Australia, Canada, Italy, Japan, Poland, Romania, South Korea, United Kingdom
Start: 20 Apr 2026
Primary completion: Jun 2029 (estimated)
Completion: Sept 2029 (estimated)
First posted: 2 Mar 2026
Last update posted: 22 Oct 2026
Conditions: Achondroplasia

Timeline

1 trial · 1 ongoing

Completed
Ongoing
Not yet recruiting
Stopped
Estimated dates (est.)
Results posted

20262027202820292030

Ph 2/3
ASPEN
NCT07441876
20 Apr 2026 to est. Sept 2029

Registry summary

Text and fields below are the sponsor's entries at ClinicalTrials.gov, shown as posted.

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.

Interventions

BMN 333Drug
Vosoritide Injection [Voxzogo]Drug

Arms6

Experimental
Phase 2: Low Dose
Participants will be randomized to receive different dose levels of BMN 333
Experimental
Phase 2: Medium Dose
Participants will be randomized to receive different dose levels of BMN 333
Experimental
Phase 2: High Dose
Participants will be randomized to receive different dose levels of BMN 333
Active comparator
Phase 2: Vosoritide
weight band dosing, Modified recombinant human C-type natriuretic peptide Vosoritide
Experimental
Phase 3: BMN 333 at selected dose after Phase 2
Active comparator
Phase 3: Vosoritide
weight band dosing, Modified recombinant human C-type natriuretic peptide Vosoritide

Primary outcomes2

Outcomes the sponsor listed as primary.

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

Secondary outcomes(16)

Phase 2: AGV at Weeks 26 and 52
Time frame · 26 and 52 weeks
Phase 2: Change from Baseline in standing height
Time frame · 26 and 52 weeks
Registry description
Measured in centimeters
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
Time frame · 52 weeks
Registry description
Measured in centimeters
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

Posted results

Values are shown as posted at ClinicalTrials.gov, with their units. PepBank has not converted, pooled or compared them.

No results are posted for this trial.

A trial that is still running, or that stopped early, may post results later.

Registry data comes from ClinicalTrials.gov. Study results come from studies, not from the registry. How PepBank works

Studies0

Studies that cite this trial.

No study cites this trial.

Eligibility

Who could join, as posted.

Sex: All
Age: from 2 Years up to 17 Years
Healthy volunteers: Not accepted

Inclusion and exclusion criteria, as posted

Inclusion Criteria: 1. 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 2. Participants must have ACH (confirmed by documented genetic testing) and open epiphyses 3. Are Tanner Stage I (Phase 2) or any Tanner stage (Phase 3) 4. Are ambulatory and able to stand without assistance Exclusion Criteria: 1. Have any short stature condition other than ACH (eg, hypochondroplasia, trisomy 21, pseudoachondroplasia, GH deficiency) 2. 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. 3. 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. 4. Have had bone fractures of the long bones or spine within 6 months prior to screening. 5. 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 6. Have been treated with GH, insulin-like growth factor 1, or anabolic steroids in the 6 months prior to treatment start

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