Vosoritide
A daily C-type natriuretic peptide analogue that speeds bone growth in children with achondroplasia
Vosoritide is a modified form of C-type natriuretic peptide, a growth-plate signal that counteracts the overactive FGFR3 receptor behind achondroplasia. Approved as Voxzogo in 2021 under accelerated approval, it adds about 1.6 cm a year of growth in children whose growth plates are still open; whether it changes adult height is not yet known.
What is it?
Achondroplasia, the most common form of dwarfism, is caused by a gain-of-function change in FGFR3, a receptor that brakes the growth plates at the ends of the long bones. C-type natriuretic peptide (CNP) works against that brake through its own receptor, NPR-B. Vosoritide is CNP modified to resist breakdown, given as a daily injection so that the growth plates stay under that counter-signal for as long as they are open. The label stops it permanently when they close.
The phase 3 trial that led to approval randomised 121 children aged 5 to under 18 to 15 micrograms per kilogram a day or placebo. After 52 weeks, yearly growth was 1.57 cm faster on vosoritide (95% CI 1.22 to 1.93). Adverse events were almost universal in both groups (98% each), mostly injection-site reactions, and none of the serious ones was judged treatment related. The authors wrote plainly that it was not known whether final adult height would increase or what the harms of long-term therapy might be.
The children kept growing faster. In the open-label extension, those randomised to vosoritide grew 4.26 cm a year at baseline, 5.39 at week 52 and 5.52 at week 104, and those switched from placebo rose from 3.81 to 5.43 cm a year. A later report compared 119 treated children with an external untreated cohort and found yearly growth higher by 1.84 cm in boys and 1.44 cm in girls across ages 6 to 16. A 2024 analysis of the same group, after about four years of treatment, found small improvements in physical and social quality-of-life scores, largest in children whose height gained most.
Younger children are a harder test. A placebo-controlled trial in 75 children under five (30 micrograms per kilogram under age two, 15 after) found a height Z-score difference of 0.25 at 52 weeks, which was not statistically significant, and injection-site reactions were common. Since an October 2023 supplement the label's indication carries no lower age limit, and its dose table starts at 3 kg.
Outside trials the effect holds. A 2026 meta-analysis of ten real-world studies covering 696 children found yearly growth 1.82 cm higher after 12 months of treatment and a height Z-score gain of 0.32, with side effects mostly limited to mild injection-site problems.
The same mechanism is being tested in hypochondroplasia, another FGFR3-related skeletal condition. An 18-month phase 2 study in 24 children found yearly growth up by 1.81 cm, and a phase 3 trial in 81 children, published in September 2026, found growth velocity 2.33 cm a year higher than placebo at 52 weeks with no serious adverse events. Vosoritide is not approved for hypochondroplasia.
Its main precaution is a short drop in blood pressure, which is why the label asks children to eat and drink about 240 to 300 mL of fluid in the hour before each injection. Children with significant heart or vascular disease and those on blood-pressure drugs were excluded from the trials, and the label does not recommend it when kidney function is below an eGFR of 60.
Mechanism of Action
Vosoritide stands in for C-type natriuretic peptide at the growth plate, where it works against the overactive FGFR3 signal that slows bone growth in achondroplasia.
NPR-B receptor
It binds natriuretic peptide receptor B on growth-plate cartilage cells, the receptor natural CNP uses.
Counters FGFR3
In achondroplasia FGFR3 is overactive and brakes cartilage cell growth; the NPR-B signal opposes that brake, so the growth plate lengthens bone faster.
Short-lived, daily
It peaks about 15 minutes after injection and has a half-life of about 21 to 28 minutes (label), so it is injected every day.
Blood-pressure effect
The label reports transient drops in blood pressure in the trials and asks for food and fluid before each dose; children on blood-pressure drugs were excluded.
Published Research
The studies behind vosoritide, read from their PubMed abstracts: the pivotal and infant trials, the long-term extensions, real-world data, and the newer hypochondroplasia trials.
The pivotal trial
In 121 children aged 5 to under 18, daily vosoritide 15 µg/kg increased annualised growth velocity by 1.57 cm a year more than placebo at 52 weeks. Adverse events were near-universal in both groups; none of the serious ones was treatment-related.
Two years on treatment
In the extension, children randomised to vosoritide grew 4.26 cm a year at baseline, 5.39 at week 52 and 5.52 at week 104, and those switched from placebo rose from 3.81 to 5.43 cm a year, with no new adverse effects.
Real-world outcomes: ten studies, 696 children
A meta-analysis of observational data found yearly growth 1.82 cm higher after 12 months (95% CI 1.46 to 2.18), height Z-score up 0.32 and a small fall in the sitting-height ratio, with adverse events mostly mild injection-site reactions.
Quality of life after about four years, 119 children
After a mean of four years on treatment, physical and social quality-of-life scores improved modestly, most in children whose height Z-score rose by one SD or more; the analysis compared them with modelled age effects in untreated people, not a randomised control.
Against untreated children
In 119 treated children compared with an external untreated cohort, annualised growth velocity was higher by 1.84 cm a year in boys and 1.44 in girls across ages 6 to 16.
Infants and toddlers
In 75 children under five (30 µg/kg under age two, 15 µg/kg after), injection-site reactions were common; the height Z-score difference against placebo at 52 weeks was 0.25, not statistically significant.
Hypochondroplasia: phase 3, 81 children
Children took vosoritide or placebo for 52 weeks. Growth velocity rose 1.95 cm a year against a fall of 0.39 on placebo, a difference of 2.33 cm a year (95% CI 1.85 to 2.82). Adverse events occurred in 87.8% against 72.5%, none grade 3 or higher, with no discontinuations or deaths.
Hypochondroplasia: phase 2, 24 children
In an 18-month single-arm study against an observation period, yearly growth rose by 1.81 cm and height SDS by 0.36. Injection-site reactions occurred in 83.3%; there were no treatment-related serious adverse events and no discontinuations.
First approval
A drug review describing vosoritide as a modified recombinant CNP analogue from BioMarin that restores chondrogenesis by binding NPR-B, opposing the FGFR3 signalling that causes achondroplasia.
Dosing Data
Vosoritide is injected under the skin once a day at a dose set by the child's actual body weight, after food and fluids, and stopped when the growth plates close.
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Side Effects & Contraindications
Reported Side Effects
From the trials above and the label.
Contraindications & Cautions
From the label (version 16).
Legal Status
Approved in the US under accelerated approval and authorised in the EU.
Frequently Asked Questions
?What is vosoritide used for?
To increase growth in children with achondroplasia whose growth plates are still open. It is a daily injection sold as Voxzogo.
?How much faster do children grow?
About 1.6 cm a year faster than on placebo in the pivotal trial, and real-world studies found a similar gain of about 1.8 cm a year.
?Does it increase adult height?
Not shown yet. Approval is based on growth velocity, and the label says continued approval may depend on confirmatory trials.
?Does it work in toddlers?
The under-five trial's height difference at one year (Z-score 0.25) was not statistically significant, although the label's indication has no lower age limit and its dose table starts at 3 kg.
?Why eat and drink before the injection?
Vosoritide can briefly lower blood pressure; the label asks for adequate food and about 240 to 300 mL of fluid in the hour before.
?How is the dose chosen?
From the child's actual body weight using the label's table, from 0.096 mg at 3 kg up to 0.8 mg at 90 kg or more, adjusted as the child grows.
?Is it used for other conditions?
Trials in hypochondroplasia found faster growth, including a phase 3 trial published in 2026, but it is not approved for that use.
?How does it relate to CNP?
It is a modified CNP that resists breakdown, though its half-life is still only about 21 to 28 minutes.
References
- [fda-pi] Voxzogo (vosoritide) for injection US prescribing information (DailyMed version 16, effective November 25, 2025); read October 1, 2026.
- [clinical-trial] Savarirayan R, et al. "Once-daily, subcutaneous vosoritide therapy in children with achondroplasia: a randomised, double-blind, phase 3, placebo-controlled, multicentre trial." Lancet, 2020;396(10252):684-692. PMID: 32891212.
- [clinical-trial] Savarirayan R, et al. "Safe and persistent growth-promoting effects of vosoritide in children with achondroplasia: 2-year results from an open-label, phase 3 extension study." Genet Med, 2021;23(12):2443-2447. PMID: 34341520.
- [pubmed] Albuquerque ALB, et al. "Real-world outcomes of vosoritide in achondroplasia: A systematic review and meta-analysis of multinational clinical evidence." Genet Med, 2026;28(3):101670. PMID: 41424367.
- [pubmed] Savarirayan R, et al. "Persistent growth-promoting effects of vosoritide in children with achondroplasia are accompanied by improvements in physical and social aspects of health-related quality of life." Genet Med, 2024;26(12):101274. PMID: 39305160.
- [clinical-trial] Savarirayan R, et al. "Sustained growth-promoting effects of vosoritide in children with achondroplasia from an ongoing phase 3 extension study." Med, 2025;6(5):100566. PMID: 39740666.
- [clinical-trial] Savarirayan R, et al. "Vosoritide therapy in children with achondroplasia aged 3-59 months: a multinational, randomised, double-blind, placebo-controlled, phase 2 trial." Lancet Child Adolesc Health, 2024;8(1):40-50. PMID: 37984383.
- [clinical-trial] Dauber A, et al. "A Phase 3 Trial of Vosoritide in Children with Hypochondroplasia." NEJM Evid, 2026:EVIDoa2600257. PMID: 42713641.
- [clinical-trial] Dauber A, et al. "Vosoritide treatment for children with hypochondroplasia: a phase 2 trial." EClinicalMedicine, 2024;71:102591. PMID: 38813446.
- [pubmed] Duggan S. "Vosoritide: First Approval." Drugs, 2021;81(17):2057-2062. PMID: 34694597.
- [other] EMA medicines dataset: Voxzogo (vosoritide), authorised August 26, 2021. Read October 5, 2026.
Sources & Citations
Studies were read from their PubMed records (October 5, 2026); the label, Drugs@FDA and the EMA database are listed below with their read dates.
Medical Disclaimer: This content is for educational and informational purposes only. It is not medical advice, and nothing here is an instruction to obtain or use any compound. Talk to a licensed clinician about your own situation.