BioMarin Pharmaceutical Inc. has presented new data demonstrating that VOXZOGO® (vosoritide) treatment significantly reduces tibial bowing in children with achondroplasia, addressing a key orthopedic complication that causes pain and often requires surgical intervention.
The findings, presented at the 2025 Joint Congress of the European Society for Paediatric Endocrinology (ESPE) and the European Society of Endocrinology (ESE) in Copenhagen, Denmark, and at the Pediatric Endocrine Society Annual Meeting (PES) in Maryland, highlight the drug's impact beyond height increase.
VOXZOGO Shows Significant Impact on Tibial Bowing
Analysis from the Phase 2 CANOPY clinical studies revealed that children receiving VOXZOGO experienced a significant reduction in tibial bowing compared to those on placebo. Importantly, this improvement was sustained in children who received treatment for several years.
"Tibial bowing can be painful and often requires surgical intervention," said Dr. Klane White, pediatric orthopedic surgeon and Rose Brown Endowed Chair of Pediatric Orthopedics at Children's Hospital Colorado. "Through my clinical practice, I have observed meaningful improvements that early treatment initiation with VOXZOGO has offered children with achondroplasia, including in proportionality, quality of life and now tibial bowing, which have the potential to improve physical well-being for these children into adulthood."
Michael Hughes, Chair of Little People of America's Biotech Industry Liaison Committee, noted the significance of these findings: "Outcomes beyond height have long been prioritized by the dwarfism community. Tibial bowing can be a source of pain and surgical intervention for some children with achondroplasia, and this research reflects an encouraging shift toward addressing a meaningful outcome to the community."
Long-Term Growth Benefits Demonstrated
The latest results from VOXZOGO's Phase 3 clinical trial, representing the longest follow-up to date, demonstrated that continuous and early treatment was associated with sustained increases in annualized growth velocity (AGV).
For the first time, researchers modeled potential final height gain for children with achondroplasia if treated early and continuously from 6 months until final adult height. The modeling indicated that VOXZOGO treatment could result in a height increase of 21.7 centimeters (95% CI, 18.7-24.6) in girls and 26.4 centimeters (95% CI, 22.9-29.8) in boys compared to untreated children.
Expanding Research to Other Skeletal Conditions
BioMarin also presented data on hypochondroplasia, another genetically defined form of skeletal dysplasia for which VOXZOGO is currently being evaluated in clinical trials. A retrospective study of more than 600 adults and children with hypochondroplasia found significantly higher rates of comorbidities, surgeries, and doctor visits compared to people without the condition.
"This research is critical to shaping a deeper understanding of hypochondroplasia and underscores the importance of early diagnosis, which allows physicians to begin working with children and their families as soon as possible," said Dr. Greg Friberg, Executive Vice President and Chief Research & Development Officer at BioMarin.
In a separate Phase 2 open-label clinical study in girls with Turner syndrome, researchers found that treatment with VOXZOGO was associated with a promising increase in annualized growth velocity at 6 months compared to baseline. Notably, growth velocity increased even in children who had previously been treated with human growth hormone and discontinued due to suboptimal results.
Safety Profile Remains Consistent
A study in Japan, presented at the 2025 American College of Medical Genetics and Genomics Annual Clinical Genetics Meeting, showed strong treatment adherence with VOXZOGO in children with achondroplasia under the age of 3, with no reported treatment-related adverse events nor any dose interruptions among 63 children followed for up to 23.7 months.
Across all studies, VOXZOGO was well-tolerated with safety results consistent with its known profile in achondroplasia. The most common side effects include injection site reactions, elevated blood alkaline phosphatase levels, vomiting, joint pain, decreased blood pressure, and stomachache.
Advancing the CANOPY Clinical Program
BioMarin continues to advance its CANOPY clinical program for VOXZOGO across multiple conditions, including hypochondroplasia, idiopathic short stature, Noonan syndrome, Turner syndrome, and SHOX deficiency.
In April, the company completed enrollment in its pivotal Phase 3 study of VOXZOGO in hypochondroplasia and is on track to share topline data in 2026, with potential launch in 2027.
About Achondroplasia and VOXZOGO
Achondroplasia, the most common form of skeletal dysplasia, is characterized by impaired bone growth caused by a change in the FGFR3 gene. The condition affects approximately one in 25,000 live births worldwide, with more than 80% of cases resulting from spontaneous gene mutations in children with parents of average stature.
VOXZOGO is a C-type natriuretic peptide (CNP) analog that acts as a positive regulator of the signaling pathway downstream of FGFR3 to promote endochondral bone growth. It is approved in the U.S., Japan, Australia, and the EU for children with achondroplasia with open epiphyses, though age indications vary by region.
In the U.S., VOXZOGO's indication is approved under accelerated approval based on improvement in annualized growth velocity, with continued approval contingent upon verification of clinical benefit in confirmatory trials.
As BioMarin expands its research into additional skeletal conditions, the company remains committed to addressing the broader needs of patients with skeletal dysplasias beyond height alone, focusing on outcomes that can meaningfully improve quality of life and reduce the need for surgical interventions.
