Vosoritide Meets Primary Endpoint in Phase 3 Hypochondroplasia Trial, Prompting Planned sNDA Submission to FDA

BioMarin Pharmaceutical (BioMarin) announced on May 20, 2026, that the Phase 3 CANOPY-HCH-3 trial of vosoritide (Voxzogo) in children with hypochondroplasia met its primary endpoint, demonstrating a statistically significant improvement in annualized growth velocity (AGV) of 2.33 cm/yr over placebo at week 52 (p<0.0001). The findings represent the first positive pivotal trial result in hypochondroplasia, a rare skeletal dysplasia for which no therapies are currently approved by FDA or the European Medicines Agency (EMA). A supplemental new drug application (sNDA) submission to FDA is planned for the third quarter of 2026.¹

"As someone who treats children with hypochondroplasia, I find these positive results tremendously encouraging,” said Andrew Dauber, MD, lead study investigator and Chief of Endocrinology at Children's National Hospital in Washington, DC, in a company press release.¹ “Seeing these improvements in growth is a milestone we have hoped for after so many years without treatment options."

What did the CANOPY-HCH-3 trial design and primary efficacy results show?

CANOPY-HCH-3 (Study 111-303) is a global, randomized, double-blind, placebo-controlled phase 3 study enrolling 80 children aged 3 to 17 years with hypochondroplasia in a 1:1 treatment allocation. The primary endpoint was changed from baseline in AGV at 52 weeks. Vosoritide produced a least-squares mean difference of +2.33 cm/yr versus placebo (p<0.0001), accompanied by statistically significant improvements in standing height (p<0.0001) and height Z-score (p<0.0001). A prespecified secondary endpoint, arm span, also showed statistically significant improvement (p=0.004), a finding considered clinically relevant given its association with reach, daily activities, and functional independence. Participants will continue into a long-term extension study. Full data are expected to be presented at an upcoming medical meeting.¹

What is hypochondroplasia, and why has the condition historically lacked approved treatments?

Hypochondroplasia is a rare autosomal dominant skeletal dysplasia caused predominantly by gain-of-function variants in the fibroblast growth factor receptor 3 gene (FGFR3), most commonly the p.Asn540Lys substitution, though the genotype–phenotype relationship is variable.² The condition is characterized by disproportionate short stature, rhizomelic limb shortening, and potential complications including spinal stenosis, otolaryngologic involvement, and neurodevelopmental concerns.²

Clinical presentation is often milder and more heterogeneous than achondroplasia, which has contributed to diagnostic delays and historically complicated trial enrollment.³ No therapies have been approved by any regulatory agency for hypochondroplasia to date.¹

How does vosoritide's mechanism of action address FGFR3-mediated skeletal dysplasia?

Vosoritide is a C-type natriuretic peptide analogue that acts downstream of FGFR3 signaling by activating the natriuretic peptide receptor B pathway, thereby promoting endochondral bone growth.⁴ The drug is approved in the United States, European Union, Japan, and Australia for achondroplasia in children with open epiphyses, with US approval granted under accelerated approval based on AGV improvement.¹

BioMarin submitted an sNDA for full achondroplasia approval in April 2026. Because hypochondroplasia shares the same pathophysiological pathway, dysregulated FGFR3 signaling, vosoritide's mechanism provides a pharmacological rationale for its investigation in this related condition.⁴

What limitations apply to these results, and what regulatory and data disclosures are anticipated?

Full CANOPY-HCH-3 results have not yet been published or presented at a peer-reviewed forum, limiting independent assessment of the complete dataset, including subgroup analyses, health-related quality of life outcomes, and upper-to-lower body segment ratio changes. In addition to the planned sNDA submission to FDA in the 2026 third quarter, the company also expects to file regulatory submissions in this indication with EMA and other regional authorities.¹

References

1. BioMarin Pharmaceutical. biomarin announces positive phase 3 pivotal study results for Voxzogo (vosoritide) in children with hypochondroplasia. Published May 20, 2026. Accessed May 22, 2026. https://www.biomarin.com/news/press-releases/biomarin-announces-positive-phase-3-pivotal-study-results-for-voxzogo-vosoritide-in-children-with-hypochondroplasia/
2. Bober MB, Bellus GA, Nikkel SM, Tiller GE. Hypochondroplasia. In GeneReviews; Adam MP, Feldman J, Mirzaa GM, et al, eds.. University of Washington, Seattle; 1999. Updated Sept. 25, 2025. Accessed May 22, 2026. https://www.ncbi.nlm.nih.gov/books/NBK1477/
3. Hoover-Fong J, Scott CI, Jones MC; Committee on Genetics. Health supervision for people with achondroplasia. Pediatrics. 2020;145(6):e20201010. doi:10.1542/peds.2020-1010
4. Savarirayan R, Irving M, Bacino CA, et al. C-type natriuretic peptide analogue therapy in children with achondroplasia. N Engl J Med. 2019;381(1):25-35. doi:10.1056/NEJMoa1813446