BioMarin's Strategic Move: Voxzogo Label Expansion Insights

Key Takeaways

• FDA expanded Voxzogo's indication to children under 5 on October 20, 2023, based on Study 111-206 efficacy and safety data.
• Phase 2 trial in 75 children aged 4 months to under 5 demonstrated 0.8 cm greater height gain versus placebo at 52 weeks with a safety profile matching older pediatric patients.
• BioMarin guides 2026 Voxzogo revenue at $975 million–$1.025 billion, with approximately 73% coming from markets outside the U.S. according to Q1 2026 earnings.
• Voxzogo is the only FDA-approved therapy for achondroplasia, a rare genetic condition affecting endochondral bone growth through FGFR3 pathway overactivation.
• BioMarin expects Phase 3 hypochondroplasia data in H1 2026, with potential regulatory submissions in H2 2026 for a second indication expansion.

What Approval Did Voxzogo Receive?

The FDA granted a supplemental New Drug Application (sNDA) approval for Voxzogo on October 20, 2023. This expanded the indication from children aged 5 years and older to include all pediatric patients with open epiphyses (growth plates).

The approval was based on data from Phase 2 Study 111-206, which enrolled 75 children aged 4 months to under 5 years with achondroplasia. Results showed treated children grew 0.8 cm more than placebo recipients over 52 weeks (95% CI: 0.02–1.54). Height Z-score improvements were consistent with findings in older children from the Phase 3 trial.

The European Medicines Agency (EMA) had previously approved Voxzogo on August 26, 2021, for patients aged 4 months and older. This broader initial indication meant the U.S. approval effectively harmonized the eligible population across major regulatory markets.

How Does Voxzogo Work?

Voxzogo (vosoritide) is a C-type natriuretic peptide (CNP) analog developed to counteract the underlying molecular defect in achondroplasia. The condition results from a gain-of-function mutation in the fibroblast growth factor receptor 3 (FGFR3) gene, which produces excessive signaling that inhibits endochondral bone growth.

By binding to natriuretic peptide receptor-B (NPR-B), vosoritide activates the cyclic guanosine monophosphate (cGMP) pathway and suppresses extracellular signal-regulated kinases 1 and 2 (ERK1/2) signaling. This counteracts FGFR3 overactivity and promotes chondrocyte proliferation and differentiation, enabling linear growth in children with open growth plates.

FDA prescribing information identifies urinary cGMP and serum collagen type X marker (CXM) as biomarkers of vosoritide pharmacologic activity.

What Clinical Data Supports the Label Expansion?

The pediatric under-5 approval rested primarily on Study 111-206, a Phase 2 trial evaluating vosoritide's safety and efficacy in younger children. Key metrics from this and related studies include:

Table: Voxzogo Clinical Trial Summary

Study	Phase	Population	Primary Endpoint Result
111-206	2	4 months to <5 years (n=75)	+0.8 cm height vs. placebo (52 weeks)
111-301	3	5–15 years (n=121)	+1.57 cm height vs. placebo (AGV)
111-302	3 Extension	Long-term follow-up	Sustained growth through 4 years

Injection site reactions occurred in 86% of patients, while rash affected 28%. The safety profile in children under 5 mirrored that observed in older pediatric populations. ClinicalTrials.gov NCT03583697 lists the Phase 2 study protocol.

What Is the Commercial Impact?

Voxzogo generated $220 million in Q1 2026, a 3% increase from $214 million in Q1 2025 according to BioMarin's earnings report. The drug now reaches patients across 55 commercial markets globally.

Approximately 73% of Voxzogo revenue originates from markets outside the United States. BioMarin has guided full-year 2026 Voxzogo revenue at $975 million to $1.025 billion, reflecting continued penetration in incident and established growth markets.

The company reports patient counts increased by more than 20% year-over-year in Q1 2026, driven by expanded diagnosis and treatment initiation programs. International market access negotiations remain active, with short-term pricing considerations potentially traded for broader patient access.

What Pipeline Extensions Are Under Development?

BioMarin is advancing Voxzogo into additional indications beyond achondroplasia. The Phase 3 program for hypochondroplasia—a related skeletal dysplasia characterized by milder short stature—expects topline data in the first half of 2026.

If positive, regulatory submissions for hypochondroplasia would follow in the second half of 2026, with potential approval in 2027. This would mark Voxzogo's second approved indication and could expand the treatable population significantly.

The company is also evaluating vosoritide in other growth disorders, including studies for idiopathic short stature, Noonan syndrome, Turner syndrome, and SHOX deficiency.

What Is the Competitive Position?

Voxzogo remains the sole FDA-approved pharmacotherapy for achondroplasia. No direct competitors have reached the market, though several programs are in development including antibody and gene therapy approaches.

Key competitive factors include:

• First and only approved therapy with real-world evidence spanning multiple years
• Subcutaneous once-daily dosing that families can administer at home
• Broad label covering ages 4 months and older in Europe, with aligned U.S. approval
• Established reimbursement pathways in major markets

The expansion to younger patients enables earlier treatment initiation, potentially maximizing growth velocity improvements before epiphyseal closure. This positions BioMarin to capture incident patients earlier in the treatment journey.

Frequently Asked Questions

Primary Sources

1. BioMarin Press Release: FDA Approves Voxzogo for Children Under 5 (October 20, 2023)
2. FDA Prescribing Information for Voxzogo (vosoritide) (Updated Label, 2024)
3. ClinicalTrials.gov: Phase 2 Study of Vosoritide in Children <5 Years (NCT03583697)
4. EMA: Voxzogo European Public Assessment Report (August 26, 2021)
5. BioMarin Q1 2026 Earnings Release and Financial Guidance
6. ClinicalTrials.gov: Phase 3 Study of Vosoritide in Achondroplasia (NCT03197766)