Vosoritide
Verdict card (component)
✓ Established | for achondroplasia in children
A C-type natriuretic peptide (CNP) analog approved for height growth in children with achondroplasia. FDA-approved 2021 (Voxzogo) and EMA-approved same year. Phase 3 trials showed approximately 1.6 cm/year increase in growth velocity over placebo in children aged 5–18. The approval ended a 20-year period in which there was no disease-modifying therapy for achondroplasia — the most common form of dwarfism, affecting ~1 in 25,000 births. Daily subcutaneous injection.
Evidence signal row
- ✓ Phase 3 RCT evidence in children aged 5–18 with achondroplasia
- ✓ First disease-modifying therapy for achondroplasia
- ! Long-term outcomes (final adult height, function) still maturing
Our verdict (4 sentences)
Vosoritide is a real disease-modifying therapy for a condition that previously had none. The Phase 3 evidence is solid for the surrogate endpoint (annualized growth velocity), and the FGFR3-pathway mechanism is well-characterized. The remaining open question — whether the height gain translates to meaningful long-term functional benefit (joint, spinal, neurologic outcomes that drive quality of life in achondroplasia) — is being studied but won’t have multi-decade answers for a while. We rate it Established with the standard caveat that the Established verdict applies to growth velocity in childhood; the longer-term clinical-outcome story is still developing.
Mechanism
Vosoritide is a recombinant 39-amino-acid peptide modeled on native C-type natriuretic peptide (CNP). Native CNP has a half-life of ~3 minutes in serum; vosoritide is engineered for protease resistance, extending the half-life to ~28 minutes — enough for once-daily subcutaneous dosing.
Achondroplasia is caused by an activating mutation in FGFR3 (fibroblast growth factor receptor 3), almost always at position G380R. The mutation increases FGFR3 signaling at the cartilage growth plate, suppressing chondrocyte proliferation and reducing endochondral bone growth — the mechanism that produces the characteristic short-limbed phenotype.
CNP signaling counteracts FGFR3 activation. Vosoritide binds the natriuretic peptide receptor B (NPR-B) on chondrocytes, activating cGMP-dependent signaling that inhibits the MAPK pathway downstream of FGFR3. Net effect: chondrocyte proliferation increases, growth plate function recovers, and longitudinal bone growth accelerates.
The mechanism is specific to the FGFR3 axis — it doesn’t broadly stimulate growth in unaffected tissues. Vosoritide doesn’t significantly increase growth velocity in children without achondroplasia.
What the evidence shows
Phase 2 (Savarirayan et al, NEJM 2019): Open-label, dose-finding study in 35 children aged 5–14. Established the 15 mcg/kg daily dose as effective for increasing growth velocity.
Phase 3 (Savarirayan et al, Lancet 2020): Randomized double-blind placebo-controlled trial in 121 children aged 5–18 with achondroplasia. Primary endpoint: annualized growth velocity at 52 weeks. Result: vosoritide group +1.57 cm/year over placebo (5.71 vs 4.06 cm/year). Statistically significant; clinically meaningful for a population whose untreated growth velocity is well below population norms.
Phase 3 extension and follow-on studies: Continued growth velocity benefit demonstrated through 2+ years of treatment in extension cohorts. Younger-age expansion trials (children 4 months–5 years) reading out 2024–2026.
What remains open:
- Final adult height — patients in the original trials are still growing; multi-year follow-up needed
- Functional outcomes — does the increased height translate to reduced spinal stenosis, improved joint mechanics, fewer surgical interventions? Long-term observational data needed
- Cardiovascular safety — CNP signaling has cardiovascular effects; ongoing post-marketing surveillance
The evidence is enough for the Established verdict on the growth-velocity endpoint. The functional-outcomes and final-height story will define how this drug is positioned long-term.
Dosing literature
Approved dosing (subcutaneous, once daily):
- 15 mcg/kg/day, with weight-adjusted dose vials
- Administered subcutaneously, typically in evening (mimics endogenous CNP circadian rhythm)
- Continued through skeletal maturity (closure of growth plates)
The daily injection burden is significant for pediatric patients — adherence is a real clinical concern. Vials require refrigeration. Long-acting formulations are in development but not yet approved.
Risks and adverse events
Common (Phase 3 data):
- Injection site reactions (very common — erythema, swelling, occasional pain)
- Vomiting, mostly mild
- Headache
- Brief blood pressure decrease in the hour after injection (vosoritide has natriuretic/vasodilator activity at peak concentrations)
Less common but monitored:
- Symptomatic hypotension, especially in younger or smaller patients
- Joint pain
- Fatigue
Pre-treatment screening required:
- Echocardiogram (CNP receptor distribution includes cardiac tissue; cardiac safety is monitored)
- Blood pressure assessment
- Clinical confirmation of achondroplasia diagnosis (FGFR3 G380R or related activating mutation)
Long-term concerns: Largely uncharacterized. Cardiovascular surveillance is part of post-marketing requirements.
Regulatory status
| Region | Status | Notes |
|---|---|---|
| United States | Approved (Voxzogo) | Original approval Nov 2021 for children with achondroplasia ≥5 years. Expanded October 20, 2023 to children of all ages with achondroplasia and open epiphyses (i.e., still growing). |
| European Union | Approved | Pediatric indication; current EMA labeling covers children ≥4 months with open epiphyses. |
| United Kingdom | Approved | NHS access via specialized commissioning. |
| Australia | Approved | |
| Japan | Approved |
Manufacturer: BioMarin Pharmaceutical. The drug is expensive (~$320,000/year US list price); access in most markets is gated through specialized pediatric endocrinology or genetics clinics.
Where to get it
Through a pediatric endocrinologist or geneticist with expertise in skeletal dysplasia, accessed via specialty pharmacy. Achondroplasia is rare; the prescribing community is small and concentrated in academic medical centers.
We have no fulfillment partner for vosoritide. (See How we make money.)
References (selected)
- 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. PubMed
- Savarirayan R et al. C-Type Natriuretic Pepti
Quick Facts
| Also Known As | BMN-111, C-type Natriuretic Peptide analog, CNP analog |
|---|---|
| Sequence | Single-letter: GLSKGCFGLKLDRIGSMSGLGC |
| Molecular Formula | C176H290N56O51S3 |
| Molecular Weight | 4103 Da |
| PubChem CID | 119058036 |
Research Parameters
| Half-Life | Approximately 20-30 minutes in circulation (based on natriuretic peptide pharmacokinetics; specific published half-life for vosoritide is limited). |
|---|---|
| Stability | The commercial drug product (Voxzogo) is supplied as a lyophilized powder in a single-dose vial. After reconstitution with the provided diluent, the solution should be used immediately or stored refrigerated for a very limited time as per the manufacturer's instructions. Specific stability data for research-grade material is proprietary. |
| Solubility | In clinical use, it is reconstituted with the specific sterile diluent provided by the manufacturer. For research purposes, information on optimal solvents is not publicly standardized. |
| Storage (Lyophilized) | The commercial product should be stored refrigerated at 2°C to 8°C (36°F to 46°F) in the original carton to protect from light. Do not freeze. Specifics for research-grade material are not defined. |
| Storage (Reconstituted) | After reconstitution, the solution should be used immediately. If not used immediately, it may be stored refrigerated at 2°C to 8°C (36°F to 46°F) for a very short duration (e.g., up to 24 hours) as per the specific product labeling. Do not freeze. |
| Typical Research Dose | 15 μg/kg body weight per day (clinical dose). |
| Cycle Parameters | Chronic, daily administration. In clinical practice for achondroplasia, it is a long-term daily therapy intended to be continued until growth plates fuse. |
| Amino Acid Count | 2 |
Mechanism of Action
Vosoritide is a potent agonist of the natriuretic peptide receptor B (NPR-B). Its primary mechanism involves antagonizing the pathological FGFR3 signaling cascade in chondrocytes, which is overactive in achondroplasia.
NPR-B Activation and cGMP Production: Vosoritide binds to and activates the transmembrane NPR-B receptor on chondrocytes. This activation stimulates the receptor's intrinsic guanylyl cyclase activity, leading to a significant intracellular increase in cyclic guanosine monophosphate (cGMP).
cGMP-Mediated Inhibition of MAPK Pathway: The elevated cGMP acts as a second messenger. A key downstream effect is the inhibition of the mitogen-activated protein kinase (MAPK) signaling pathway, specifically the Raf/MEK/ERK cascade. This pathway is hyperactivated by the mutant FGFR3 in achondroplasia.
Counteraction of FGFR3 Signaling: By inhibiting the MAPK pathway, vosoritide counteracts the negative effects of excessive FGFR3 signaling. This mitigates the FGFR3-induced suppression of chondrocyte proliferation and differentiation within the growth plate.
Promotion of Endochondral Ossification: The net result is a restoration toward normal chondrocyte function. This allows for improved proliferation of chondrocytes, increased extracellular matrix production, and more normalized progression through the zones of the growth plate, ultimately leading to enhanced endochondral bone growth and increased longitudinal bone length.
Research Applications
Achondroplasia Therapy: Vosoritide has been extensively researched as a daily subcutaneous therapy for children with achondroplasia. Clinical trials have demonstrated a sustained increase in annualized growth velocity compared to baseline and placebo, leading to improved height Z-scores over time. The therapy aims to ameliorate the disproportionate short stature associated with the condition.
Other Skeletal Dysplasias: Preclinical research has explored the potential of CNP analogs like vosoritide for other conditions involving impaired endochondral ossification where FGFR signaling may be dysregulated, such as hypochondroplasia or thanatophoric dysplasia. However, clinical focus remains primarily on achondroplasia.
Bone Growth and Repair: Fundamental research on the CNP-NPR-B pathway has provided insights into the regulation of growth plate physiology. This has broader implications for understanding bone development, fracture healing, and cartilage biology, although direct therapeutic application outside of genetic skeletal disorders is not the primary focus of vosoritide development.
Safety & Side Effects
The safety profile is primarily defined by clinical trials in pediatric patients with achondroplasia. Commonly reported adverse events in trials include injection site reactions (e.g., redness, swelling, itching), vomiting, cough, and fever. Hypotension (low blood pressure) has been observed, which is a known class effect of natriuretic peptides, and transient decreases in blood pressure may occur post-injection. Other reported events include headache, diarrhea, and fatigue. Serious adverse events were infrequent. Theoretical concerns based on the mechanism include potential effects on blood pressure and fluid balance. No long-term safety data beyond several years of treatment are currently available.
Dosage Information
This information is derived from published clinical trials and is presented for research understanding only. Vosoritide is a prescription medication with a defined dosing regimen.
In clinical studies for achondroplasia, vosoritide is administered as a once-daily subcutaneous injection. The dose is weight-based. In the pivotal phase 3 study, the daily dose was 15 μg per kilogram of body weight. Administration typically occurs at approximately the same time each day, independent of meals. Treatment is intended as a long-term, chronic therapy initiated in childhood and continued until growth potential is reached.
References
Savarirayan, R., et al. 'Once-daily, subcutaneous vosoritide therapy in children with achondroplasia: a randomised, double-blind, phase 3, placebo-controlled, multicentre trial.' The Lancet, vol. 396, no. 10252, 2020, pp. 684-692.
Horton, W.A., et al. 'C-type natriuretic peptide analogue therapy in children with achondroplasia.' New England Journal of Medicine, vol. 381, no. 1, 2019, pp. 25-35.
Lorget, F., et al. 'Evaluation of the therapeutic potential of a CNP analog in a Fgfr3 mouse model recapitulating achondroplasia.' American Journal of Human Genetics, vol. 91, no. 6, 2012, pp. 1108-1114.
Yasoda, A., et al. 'Overexpression of CNP in chondrocytes rescues achondroplasia through a MAPK-dependent pathway.' Nature Medicine, vol. 10, no. 1, 2004, pp. 80-86.
Wendt, D.J., et al. 'Pharmacokinetics and pharmacodynamics of BMN 111, a CNP analog for the treatment of achondroplasia.' American Journal of Human Genetics, vol. 93, no. 5, 2013, pp. 159. (Abstract).
Savarirayan, R., et al. 'C-type natriuretic peptide analogue therapy in children with achondroplasia: a phase 2 study.' Genetics in Medicine, vol. 18, 2016, pp. 133-134. (Abstract).