BioMarin Reports Positive Data of Voxzogo in Kids with Hypochondroplasia

Rare Daily Staff

BioMarin Pharmaceutical said Voxzogo increased growth rates and improved several measures of skeletal growth in children with hypochondroplasia in a phase 3 study.

The company has submitted an application to the U.S. Food and Drug Administration seeking to expand the drug’s use to hypochondroplasia, a condition for which no medicines are currently approved in the United States or Europe.

Hypochondroplasia is a rare inherited skeletal disorder that impairs bone growth. It can cause disproportionate short stature and differences in the long bones and spine, and some children may experience effects on physical function and quality of life, as well as complications involving the ears, nose and throat or the nervous system. The condition varies widely among individuals and is often diagnosed during toddlerhood or the early school years.

Voxzogo, known chemically as vosoritide, is a daily injection designed to promote endochondral bone growth, the process through which much of the skeleton develops. The drug is a synthetic version of C-type natriuretic peptide, a naturally occurring signaling molecule. BioMarin says it works downstream of the FGFR3 pathway, which is involved in regulating bone growth. Voxzogo is already approved to increase linear growth in children with achondroplasia whose growth plates remain open, but it is not approved for hypochondroplasia.

The 52-week CANOPY-HCH-3 trial compared vosoritide with placebo in children with hypochondroplasia. The study met its primary endpoint, with children receiving the drug growing an average of 2.33 centimeters per year faster than those who received placebo, a statistically significant difference.

The company also reported statistically significant advantages for vosoritide over placebo in several other measurements, including standing height, height Z-score, a measure comparing a child’s height with that of children of the same age and sex, and arm span.

Children treated with vosoritide also showed numerical, though not necessarily statistically significant, improvements in quality-of-life measures, BioMarin said. The company plans to continue following participants to evaluate longer-term effects.

“The changes we observed in annualized growth velocity and arm span provide encouraging evidence of how children with hypochondroplasia responded to treatment throughout the study,” said Andrew Dauber, chief of endocrinology at Children’s National in Washington and the study’s lead investigator.

The results were published in NEJM Evidence and presented in a late-breaking oral session at the European Society for Paediatric Endocrinology’s 2026 annual meeting.

The safety findings in the study were consistent with vosoritide’s established profile in achondroplasia, according to BioMarin. Most adverse events were mild, and investigators identified no treatment-related serious adverse events.

The drug carries important safety considerations in its currently approved use. Vosoritide can temporarily lower blood pressure, potentially causing dizziness, tiredness or nausea. Caregivers are instructed to ensure that a child eats a meal and drinks 8 to 10 ounces of fluid within an hour before the injection to reduce that risk. Common side effects include injection-site reactions, vomiting, joint pain, low blood pressure and stomach pain.