What Is Vosoritide?

1. What is achondroplasia, and how does vosoritide work?

Achondroplasia is caused by a gain-of-function change in the FGFR3 gene. FGFR3 is a receptor that acts as a brake on the growth plate, the cartilage at the ends of long bones where children grow. In achondroplasia that brake is stuck on, which slows growth and causes disproportionately short arms and legs. As Högler and Ward describe, it also causes serious medical problems such as narrowing at the base of the skull and in the spine, and airway narrowing.

CNP is the body’s own counterweight. It binds natriuretic peptide receptor B (NPR-B) on growth plate cells and raises cGMP, which blocks the signaling pathway FGFR3 uses (Ago et al., 2026). According to the Voxzogo label, vosoritide binds NPR-B and inhibits the ERK1/2 arm of the MAPK pathway at the level of RAF-1, which lets cartilage cells multiply and mature again.

Even with that resistance, vosoritide clears fast: it peaks about 15 minutes after an injection and has a half-life under half an hour. A daily injection gives the growth plate a daily pulse of CNP signaling.

2. What did the trials show in achondroplasia?

Phase 2 dose finding

Savarirayan and colleagues’ phase 2 study gave 35 children aged 5 to 14 daily doses from 2.5 to 30 mcg/kg. The 15 mcg/kg dose was the one carried into the phase 3 trial.

The phase 3 trial

The pivotal phase 3 trial randomized 121 children aged 5 to under 18 at 24 hospitals in seven countries to vosoritide 15 mcg/kg or placebo for 52 weeks. All had spent at least 6 months in a baseline growth study first, so their own growth rate before treatment was known.

Results from the label and the trial paper. A height Z-score compares a child with average-stature peers of the same age and sex. The authors wrote that “it is not known whether final adult height will be increased, or what the harms of long-term therapy might be.”

Longer follow-up

In the ongoing phase 3 extension, 119 children on daily vosoritide were compared with untreated children from a natural history study called CLARITY. Before puberty, treated children grew at about the rate of average-stature children. Over 3 years, they gained 5.75 cm (95% CI 4.93–6.57) more height than untreated peers, and body proportions improved in younger children. A 2025 review notes extension data out to seven years, real-world studies from France, Germany and Japan with similar growth gains, and early reports of less leg bowing and lower-back curvature. Comparisons with external controls are weaker evidence than a randomized trial.

Infants and young children

A randomized phase 2 trial in 75 children aged 3 to 59 months used 30 mcg/kg for those under 2 and 15 mcg/kg for those 2 to 5. Height Z-score improved by 0.25 more than placebo, with a confidence interval that just crossed zero (−0.02 to 0.53). Injection site reactions were very common. One infant in the vosoritide group died of sudden infant death syndrome, recorded among the serious adverse events. FDA used this trial to extend the label to all ages in October 2023 (Drugs@FDA).

3. What is Voxzogo approved for?

Sources: Drugs@FDA, EMA, BioMarin, July 2026.

The US label states that the indication “is approved under accelerated approval based on an improvement in annualized growth velocity.” That means FDA accepted growth rate as a surrogate and required confirmatory evidence of clinical benefit. BioMarin’s July 2026 application for full approval draws on long-term data from three ongoing studies, including growth, proportionality and adult height outcomes. BioMarin says Voxzogo is also approved in Japan and Australia for all ages, and that more than 5,000 children in over 50 countries have been treated.

4. How is vosoritide dosed?

The label sets the dose by actual body weight, once a day by injection under the skin. Selected weight bands:

Other label points:

• Before each dose, the child should have eaten adequately and drunk about 240 to 300 mL (8 to 10 oz) of fluid within the hour.
• Timing. About the same time each day, rotating sites and not using the same site two days in a row.
• Missed dose. Give it within 12 hours; after that, skip it.
• Monitoring. Weight, growth and development every 3 to 6 months, with the dose adjusted to current weight.
• Stopping. Permanently, once the growth plates close.
• Kidneys. Not recommended with an eGFR below 60.

The vials contain powder that a caregiver mixes with the supplied sterile water before injection.

5. What are the side effects and warnings?

From the 52-week phase 3 trial in the label:

Raised alkaline phosphatase, an enzyme from active bone, occurred in 17% against 7%. In children under 5, injection site reactions affected 86% and rash 28%. Excess hair growth has been reported since approval. Antibodies to vosoritide developed in about a third of children, none of them neutralizing, with no clear effect on safety or growth.

Low blood pressure

In the phase 3 trial, drops in blood pressure occurred in 13% on vosoritide and 5% on placebo. They began a median of 31 minutes after injection and lasted a median of 31 minutes. Two children had symptoms such as vomiting or dizziness. The trials excluded children with significant heart or vascular disease and those taking blood pressure medicines, so there is little data in those groups.

Slipped hip growth plates in other conditions

A 2026 case series by Kanakatti Shankar and colleagues reported slipped capital femoral epiphysis (SCFE), where the top of the thigh bone slips at the growth plate, in five participants in two investigator-run trials. In a trial covering several genetic short stature conditions, it occurred in 2 of 12 children with ACAN variants and 1 of 11 with a RASopathy, but in none of 7 with NPR2 variants or 24 with hypochondroplasia. In a Turner syndrome trial, 2 of 5 girls on vosoritide developed it. All had been treated for more than 12 months and all had the rare valgus type. The authors said vosoritide may raise SCFE risk in some genetic forms of short stature. This is not a labeled warning for achondroplasia, but it matters for the newer indications below.

6. What other conditions is vosoritide being studied for?

Because CNP signaling acts on the growth plate in general, BioMarin and academic groups are testing vosoritide in other causes of short stature. Status as listed on ClinicalTrials.gov and in company releases checked November 2026:

Hypochondroplasia

Hypochondroplasia is the furthest along. An earlier single-center phase 2 trial in 24 children found a 1.81 cm a year rise in growth rate over their own baseline, similar to achondroplasia. In the phase 3 trial published in NEJM Evidence, growth velocity rose by 1.95 cm a year on vosoritide and fell by 0.39 cm a year on placebo. There were no grade 3 or higher adverse events, discontinuations for side effects, or deaths. BioMarin reported height Z-score gains of 0.39 and said a US application had been submitted, with submissions to the EMA and others on track (BioMarin, September 2026). In 13 children followed for three years in the phase 2 extension, height Z-score improved by 0.72 (BioMarin, June 2026).

7. What are the alternatives and next-generation drugs?

Vosoritide is no longer the only targeted option for achondroplasia:

In the APPROACH trial of 84 children aged 2 to 11, weekly navepegritide improved growth over placebo; BioSpace reports the difference as 1.49 cm a year. In PROPEL 3, 114 children aged 3 to 17 grew 1.74 cm a year more on infigratinib than on placebo; in the published paper, the upper-to-lower body segment ratio did not differ significantly from placebo. These trials enrolled different children, so their numbers cannot be compared directly, and no head-to-head trial has reported. BioMarin’s ASPEN trial, with primary completion estimated for June 2029, will compare its weekly BMN 333 directly with daily vosoritide.

8. Does vosoritide have anything to do with GLP-1 drugs?

Not directly. Vosoritide and GLP-1 drugs such as semaglutide are both injected peptides, but they act on unrelated receptors. Vosoritide works on NPR-B in growth plate cartilage and is used only in children who are still growing. It has no known effect on appetite, blood sugar or weight, and no study has examined it alongside GLP-1 medicines. The label lists no drug interaction studies.

A few practical overlaps are worth knowing for families:

• Weight-based dosing. The vosoritide dose follows actual body weight in bands. Any change in weight, for whatever reason, can move a child into a different band at the next check.
• Food and fluid before doses. The label’s advice to eat and drink before each injection assumes normal appetite. Anything that sharply reduces intake, including illness or appetite-suppressing medicines, makes that harder; this combination has not been studied.
• Not a height drug for adults. Vosoritide acts on open growth plates, and the label says to stop it permanently once they close. It has not been tested to add height in adults.

For peptides that act on the growth hormone axis instead, see the HGH guide and the somapacitan page.

9. What can families track on vosoritide?

The trials measured growth rate, height and body proportions, so those records matter most:

• Height and growth velocity. Measured on the same stadiometer where possible, with dates, so annualized growth velocity can be calculated.
• Weight. To keep the dose in the right band; the label calls for checks every 3 to 6 months.
• Dose log. Daily injection time and site, missed doses and whether the 12-hour window was used.
• Pre-dose food and fluid. Especially early in treatment or during illness.
• Reactions. Dizziness, vomiting or pallor within the first hour, and injection site reactions.
• Bones and joints. Joint pain, limping, or hip or knee pain, which should be reported promptly given the SCFE reports in other conditions.
• Specialist results. Growth plate assessments and any orthopedic or sleep study findings.

A peptide tracker or spreadsheet can keep that history organized for clinic visits. Decisions about starting, dosing and stopping vosoritide belong with the child’s specialist team.

10. Vosoritide FAQ

• What is vosoritide used for?

  It is approved to increase linear growth in children with achondroplasia whose growth plates are still open. In the US that covers children of all ages, under accelerated approval. In the EU it covers children from 4 months whose diagnosis has been confirmed by genetic testing. It is not approved for other conditions as of November 2026.

• How much taller does vosoritide make children?

  In the phase 3 trial, children grew 1.57 cm a year more than on placebo over 52 weeks. In the extension, 3-year height gain was 5.75 cm more than in untreated children from a natural history study. Whether this adds up to a taller final adult height has not yet been confirmed in published data.

• Does vosoritide work in adults?

  No. It acts on the growth plates at the ends of long bones, which close after puberty. The label says to stop permanently once the growth plates have closed, and it has not been tested to increase height in adults.

• What are the side effects of vosoritide?

  Injection site reactions such as redness, swelling and hives are the most common. Vomiting, joint pain, dizziness, diarrhea and a brief drop in blood pressure were more frequent than on placebo. Raised alkaline phosphatase, a bone enzyme, was also more common.

• Why must children eat and drink before a vosoritide injection?

  Vosoritide can briefly lower blood pressure, usually around 30 minutes after an injection. The label asks for adequate food and about 240 to 300 mL (8 to 10 oz) of fluid in the hour before each dose to reduce the chance of dizziness or vomiting.

• Is vosoritide approved for hypochondroplasia?

  Not yet. A phase 3 trial of 81 children found 2.33 cm a year more growth than placebo, and BioMarin said in September 2026 that it had submitted an application to the FDA, with a possible US launch in 2027 if approved. No regulator has approved it for hypochondroplasia as of November 2026.

• How does vosoritide compare with navepegritide and infigratinib?

  Navepegritide (Yuviwel, Ascendis) is a weekly CNP prodrug that FDA approved in February 2026 for children 2 and older. Infigratinib (BridgeBio) is an oral FGFR3 inhibitor with a positive phase 3 trial. Vosoritide is a daily injection. No head-to-head trials between them have been published.

• Is vosoritide related to GLP-1 drugs?

  No. Both are peptide drugs, but vosoritide acts on the CNP receptor NPR-B in growth plates and has no known effect on appetite or blood sugar. No study has looked at vosoritide in combination with GLP-1 medicines.

11. Sources