Voxzogo: Uses, Dosage & Side Effects

A C-type natriuretic peptide analog for the treatment of achondroplasia in patients aged 2 years and older with open growth plates

Rx ATC: M05BX06 CNP Analog
Active Ingredient
Vosoritide
Available Forms
Powder & solvent for injection
Strengths
0.4 mg, 0.56 mg, 1.2 mg
Manufacturer
BioMarin International Limited

Voxzogo (vosoritide) is a prescription medication used to treat achondroplasia, the most common form of disproportionate short stature, in patients aged 2 years and older whose growth plates (epiphyseal plates) have not yet closed. Vosoritide is an analog of C-type natriuretic peptide (CNP), a naturally occurring protein that promotes bone growth. By counteracting the overactive fibroblast growth factor receptor 3 (FGFR3) signaling pathway—the underlying cause of impaired bone growth in achondroplasia—Voxzogo promotes endochondral ossification and increases linear growth. Administered as a once-daily subcutaneous injection, Voxzogo has been shown in pivotal clinical trials to significantly increase annualized growth velocity in children with achondroplasia, representing the first pharmacological therapy specifically approved for this condition.

Quick Facts: Voxzogo

Active Ingredient
Vosoritide
Drug Class
CNP Analog
ATC Code
M05BX06
Common Uses
Achondroplasia
Available Forms
SC Injection
Prescription Status
Rx Only

Key Takeaways

  • Voxzogo (vosoritide) is the first pharmacological treatment specifically approved for achondroplasia, targeting the underlying FGFR3 signaling pathway that impairs bone growth in this genetic condition.
  • Administered as a once-daily subcutaneous injection, Voxzogo is indicated for patients aged 2 years and older whose growth plates remain open, with the dose calculated based on body weight.
  • In the pivotal Phase 3 clinical trial (Study 111-301), Voxzogo-treated children gained an average of 1.57 cm per year more in height compared to placebo, with sustained benefits observed over multiple years in extension studies.
  • The most common side effects are injection site reactions and transient blood pressure decreases; eating a light snack and drinking fluids 30 minutes before injection can help minimize symptoms.
  • Voxzogo must be reconstituted from powder before each injection and should be stored refrigerated (2–8 °C), though it can be kept at room temperature (below 30 °C) for up to 90 days.

What Is Voxzogo and What Is It Used For?

Quick Answer: Voxzogo (vosoritide) is a C-type natriuretic peptide (CNP) analog used to treat achondroplasia in patients aged 2 years and older with open growth plates. It works by counteracting the overactive FGFR3 signaling that suppresses bone growth, thereby promoting linear skeletal growth in affected individuals.

Voxzogo contains the active substance vosoritide, a modified analog of C-type natriuretic peptide (CNP). CNP is a naturally occurring protein in the human body that plays a critical role in regulating endochondral bone growth—the process by which cartilage in the growth plates is converted into bone, resulting in longitudinal growth of the skeleton. Vosoritide is produced using recombinant DNA technology in Escherichia coli bacteria that have been genetically modified to express the gene encoding this therapeutic protein.

Achondroplasia is the most common form of disproportionate short stature (commonly referred to as dwarfism), affecting approximately 1 in 15,000 to 40,000 live births worldwide. It is caused by a gain-of-function mutation in the fibroblast growth factor receptor 3 (FGFR3) gene, located on chromosome 4. In more than 97% of cases, the specific mutation is a glycine-to-arginine substitution at position 380 (p.Gly380Arg). This mutation causes the FGFR3 receptor to be constitutively overactive, sending excessive inhibitory signals through the mitogen-activated protein kinase (MAPK) pathway that suppresses chondrocyte proliferation and differentiation in the growth plates of long bones. The result is impaired endochondral ossification, leading to shortened limbs, a characteristic facial profile with frontal bossing and midface hypoplasia, and a range of medical complications including spinal stenosis, foramen magnum compression, and recurrent ear infections.

Under normal physiological conditions, CNP acts as an important positive regulator of bone growth by binding to its receptor, natriuretic peptide receptor B (NPR-B), on chondrocytes within the growth plate. Activation of NPR-B stimulates the production of intracellular cyclic guanosine monophosphate (cGMP), which in turn inhibits the RAF-1/MEK/ERK component of the MAPK signaling cascade. In healthy individuals, this CNP-mediated pathway helps to balance the growth-inhibitory signals from FGFR3. However, in achondroplasia, the overactive FGFR3 overwhelms the natural CNP counterbalance, resulting in net suppression of bone growth.

Vosoritide was designed to restore this balance. As a CNP analog with enhanced resistance to enzymatic degradation (compared to endogenous CNP, which has a half-life of only 2–3 minutes), vosoritide provides sustained activation of the NPR-B receptor and downstream cGMP signaling. This effectively counteracts the excessive FGFR3/MAPK inhibition and allows more normal chondrocyte function in the growth plate, promoting linear bone growth. Preclinical studies in mouse models of achondroplasia demonstrated significant improvements in bone length with vosoritide treatment, providing the scientific foundation for clinical development.

Voxzogo is specifically indicated for the treatment of achondroplasia in patients aged 2 years and older whose epiphyseal growth plates are still open (i.e., who are still growing). The diagnosis must be confirmed through genetic testing demonstrating pathogenic FGFR3 mutations. Voxzogo should not be used in patients whose growth plates have fused, as the mechanism of action depends on active endochondral ossification.

The clinical efficacy of Voxzogo was established in the pivotal Phase 3 randomized, double-blind, placebo-controlled trial (Study 111-301), which enrolled 121 children aged 5 to 18 years with achondroplasia. Over a 52-week treatment period, patients receiving vosoritide 15 micrograms per kilogram per day showed a statistically significant and clinically meaningful increase in annualized growth velocity compared with placebo. The mean difference in annualized growth velocity was 1.57 cm per year (p < 0.001) in favor of vosoritide. This represented a 50% improvement over the natural growth rate observed in the placebo group. Long-term extension data from studies spanning up to 5 years have demonstrated that these growth benefits are sustained with continued treatment, with no evidence of growth velocity attenuation over time.

Voxzogo was first approved by the European Medicines Agency (EMA) in August 2021 and by the U.S. Food and Drug Administration (FDA) in November 2021. It was subsequently approved in Japan, Australia, Brazil, and numerous other countries worldwide. In 2023, the indication was extended to include children as young as 2 years of age based on additional safety and efficacy data from the Phase 2 study (111-205) conducted in younger children. Voxzogo represents a paradigm shift in the management of achondroplasia, offering the first targeted pharmacological therapy for a condition that was previously managed only through surgical interventions (limb lengthening) and symptomatic treatment of complications.

Understanding Achondroplasia

Achondroplasia affects approximately 250,000 people worldwide. While it is a genetic condition, approximately 80% of cases arise from new (de novo) mutations, meaning neither parent carries the mutation. Voxzogo does not correct the underlying genetic defect but addresses its downstream consequences on bone growth. Treatment is most effective when started early in childhood, while growth plates remain active, and should be combined with comprehensive medical management including regular monitoring for spinal stenosis, hearing assessments, and developmental evaluations as recommended by international clinical guidelines.

What Should You Know Before Taking Voxzogo?

Quick Answer: Before starting Voxzogo, inform your doctor about any heart conditions, blood pressure problems, or current medications that lower blood pressure. Voxzogo is contraindicated in patients with known hypersensitivity to vosoritide or any of its excipients, and it is not recommended during pregnancy or breastfeeding.

Contraindications

Voxzogo must not be used in patients who are allergic (hypersensitive) to vosoritide or to any of the other ingredients contained in the formulation. The excipients include citric acid, sodium citrate, trehalose dihydrate, mannitol, methionine, and polysorbat 80. If a patient has experienced any allergic reaction to these substances in the past, this should be communicated to the prescribing physician before treatment initiation. Allergic reactions to medications can range from mild skin reactions to severe anaphylaxis, and any history of such reactions warrants careful evaluation before starting therapy.

Warnings and Precautions

Before starting treatment with Voxzogo, patients and their caregivers should discuss the following with their healthcare provider:

  • Heart disease or blood pressure problems: Voxzogo can cause a temporary decrease in blood pressure following injection. This hypotensive effect is a pharmacological consequence of CNP receptor activation, which promotes vasodilation. Patients with pre-existing cardiovascular conditions or blood pressure abnormalities may be at increased risk for symptomatic hypotension. Healthcare providers should carefully evaluate the risk-benefit ratio in these patients and may need to implement additional monitoring during the initial treatment period.
  • Concurrent antihypertensive medications: Patients who are currently taking or have recently taken medications that lower blood pressure (antihypertensives) may experience an additive blood pressure lowering effect when combined with Voxzogo. This includes beta-blockers, ACE inhibitors, angiotensin receptor blockers (ARBs), calcium channel blockers, and diuretics. Dose adjustments of antihypertensive medications may be necessary, and patients should be monitored more closely during co-administration.
  • Blood pressure effects: Voxzogo can lower blood pressure, which may cause symptoms such as dizziness, nausea, or fatigue. These effects are typically transient and resolve within approximately 90 minutes after the injection. To reduce the likelihood and severity of blood pressure-related symptoms, patients are recommended to eat a light snack and drink a glass of fluid (such as water, milk, or juice) approximately 30 minutes before each injection. If symptoms are severe or persistent, patients should contact their healthcare provider.
Important: Pre-injection Preparation

Eating a light snack and drinking fluids approximately 30 minutes before each Voxzogo injection can significantly reduce the risk of dizziness, nausea, and fatigue caused by transient blood pressure decreases. This simple precaution is recommended for all patients receiving Voxzogo.

Children Under 2 Years

There is insufficient clinical data on the use of Voxzogo in children under 2 years of age, and treatment in this age group is therefore not recommended. Clinical trials have primarily included children aged 2 years and older, and the safety and efficacy profile in younger infants has not been established. Research is ongoing to evaluate the potential for earlier treatment initiation, but until adequate data are available, physicians should not prescribe Voxzogo for children below the approved age threshold.

Other Medications and Voxzogo

Patients should inform their healthcare provider about all medications they are currently taking, have recently taken, or may be planning to take. While no formal drug interaction studies have been conducted with Voxzogo, the pharmacological profile of vosoritide—specifically its blood pressure lowering properties—warrants caution when used concurrently with other agents that affect blood pressure. Vosoritide is a peptide that is expected to be degraded by endopeptidases rather than being metabolized by hepatic cytochrome P450 enzymes, which reduces the likelihood of traditional pharmacokinetic drug-drug interactions.

Pregnancy and Breastfeeding

Voxzogo is not recommended for use during pregnancy or breastfeeding. While achondroplasia is a pediatric condition and the majority of patients treated with Voxzogo are children, it is possible that patients of reproductive age may be receiving treatment. If a patient becomes pregnant or plans to become pregnant while on Voxzogo therapy, they should consult their physician immediately. There are no adequate clinical data on the use of vosoritide in pregnant women. Animal reproductive toxicology studies have not revealed direct harmful effects on embryo-fetal development; however, as a precaution, Voxzogo should only be used during pregnancy if the potential benefit justifies the potential risk to the fetus. It is not known whether vosoritide is excreted in human breast milk.

Driving and Operating Machinery

Voxzogo may cause dizziness, fatigue, or nausea shortly after injection due to its blood pressure lowering effects. If these symptoms occur, patients should not drive, cycle, engage in strenuous physical activity, or operate machinery for approximately one hour after the injection or until they feel better. Caregivers should be aware of this precaution and plan injection times accordingly, particularly for adolescent patients who may be of driving age.

Sodium Content

Voxzogo contains less than 1 mmol (23 mg) of sodium per dose, meaning it is essentially sodium-free. This is relevant for patients on sodium-restricted diets and can be reassuring for parents and caregivers concerned about sodium intake in their child's medications.

How Does Voxzogo Interact with Other Drugs?

Quick Answer: No formal drug interaction studies have been conducted with Voxzogo. However, because vosoritide can lower blood pressure, caution is advised when used alongside antihypertensive medications. Vosoritide is degraded by endopeptidases rather than hepatic enzymes, reducing the risk of traditional drug-drug interactions.

Because vosoritide is a peptide analog of C-type natriuretic peptide, it follows a metabolic pathway distinct from that of most small-molecule drugs. Rather than being metabolized by the cytochrome P450 (CYP) enzyme system in the liver, vosoritide is expected to be degraded by neutral endopeptidases and other proteolytic enzymes in the circulation and tissues. This metabolic profile significantly reduces the potential for pharmacokinetic interactions with other medications that are substrates, inducers, or inhibitors of CYP enzymes.

Nonetheless, pharmacodynamic interactions are possible, particularly with agents that affect blood pressure. The table below summarizes the key considerations for drug interactions with Voxzogo:

Voxzogo Drug Interaction Summary
Drug Class Examples Interaction Type Clinical Significance
Antihypertensives ACE inhibitors, ARBs, beta-blockers, calcium channel blockers Additive blood pressure lowering Monitor blood pressure; may increase risk of symptomatic hypotension
Diuretics Furosemide, hydrochlorothiazide, spironolactone Additive blood pressure lowering, volume depletion Ensure adequate hydration; monitor for dizziness
Nitrates Nitroglycerin, isosorbide mononitrate Additive vasodilation Potential for significant hypotension; use with caution
PDE5 Inhibitors Sildenafil, tadalafil Additive vasodilation via cGMP pathway Theoretical risk; clinical significance unknown in pediatric population
Growth Hormone Somatotropin Both affect bone growth pathways Co-administration not studied; discuss with specialist

It is important to note that the majority of patients receiving Voxzogo are children, who are less likely to be taking cardiovascular medications. However, some adolescents or young adults with achondroplasia may have comorbidities requiring such treatments, and clinicians should always perform a thorough medication review before initiating Voxzogo therapy. All current, recent, and planned medications should be disclosed to the prescribing physician, including over-the-counter products and herbal supplements.

What Is the Correct Dosage of Voxzogo?

Quick Answer: Voxzogo is administered as a once-daily subcutaneous injection at a dose of 15 micrograms per kilogram of body weight. The dose is calculated by the prescribing physician based on the patient's weight, and three vial strengths (0.4 mg, 0.56 mg, 1.2 mg) are available to accommodate different weight ranges.

Voxzogo should always be used exactly as directed by the prescribing physician. A healthcare provider should administer or supervise the first injections and provide comprehensive training to caregivers before they begin administering Voxzogo at home. The recommended dose is 15 micrograms per kilogram of body weight, given once daily as a subcutaneous injection.

Dosage by Body Weight

The physician will determine the appropriate injection volume based on the patient's body weight and the concentration of the reconstituted solution. Three vial strengths are available, each designed for specific weight ranges:

Voxzogo Vial Strengths and Corresponding Weight Ranges
Vial Strength Reconstituted Concentration Approximate Weight Range Max Injection Volume
0.4 mg 0.8 mg/mL (in 0.5 mL) 10–17 kg 0.5 mL
0.56 mg 0.8 mg/mL (in 0.7 mL) 17–33 kg 0.7 mL
1.2 mg 2 mg/mL (in 0.6 mL) 33–60+ kg 0.6 mL

Administration Instructions

Voxzogo is supplied as a powder that must be reconstituted with the provided sterile water for injection before use. Caregivers should follow these key principles when administering the injection:

  • Pre-injection preparation: The patient should eat a light snack and drink a glass of water, milk, or juice approximately 30 minutes before the injection to minimize the risk of dizziness, fatigue, or nausea from transient blood pressure reduction.
  • Reconstitution: Remove the cap from the vial, clean the top with an alcohol swab, and slowly inject the provided solvent (sterile water for injection) into the vial. Gently swirl (do not shake) the vial until the powder is completely dissolved and the solution is clear to slightly yellow and free of particles.
  • Injection technique: Using the dosing syringe, draw up the prescribed volume. Inject slowly under the skin (subcutaneously) at a 45-degree angle into one of the recommended injection sites: back of the upper arms, thighs, abdomen (at least 5 cm from the navel), or buttocks.
  • Injection site rotation: Rotate injection sites daily and do not inject into the same location on consecutive days. Avoid areas of skin that are tender, red, hard, scarred, or bruised.
  • Timing: Administer the injection at approximately the same time each day to maintain consistent drug levels.

Missed Dose

If a dose is missed, it may still be given if it is within 12 hours of the scheduled injection time. If more than 12 hours have passed since the dose was due, the missed dose should be skipped entirely. The patient should resume the regular dosing schedule the next day at the usual time. Do not administer a double dose to make up for a missed injection.

Overdose

If a dose larger than prescribed is accidentally administered, the patient or caregiver should contact their physician immediately. Overdose with vosoritide may result in more pronounced blood pressure lowering effects, including significant hypotension with symptoms such as severe dizziness, lightheadedness, or fainting. Symptomatic and supportive measures should be implemented as appropriate, including placing the patient in a supine position with legs elevated and monitoring vital signs until symptoms resolve.

Important: Do Not Discontinue Without Medical Advice

If you are considering stopping Voxzogo treatment, always consult with your child's physician first. Abrupt discontinuation will result in the loss of growth benefits provided by the medication. The decision to continue or stop treatment should be made collaboratively between the family and the medical team based on growth response, tolerability, and individual patient factors.

What Are the Side Effects of Voxzogo?

Quick Answer: The most common side effects of Voxzogo are injection site reactions (redness, itching, swelling, pain, bruising), vomiting, and transient low blood pressure causing dizziness, fatigue, or nausea. These effects are generally mild and resolve without treatment. Injection site reactions typically fade within a few hours.

Like all medications, Voxzogo can cause side effects, although not everyone who takes it will experience them. The side effects observed in clinical trials were generally mild to moderate in severity and transient in nature. The safety profile of Voxzogo has been evaluated in multiple clinical trials involving over 400 patients with achondroplasia, with the longest follow-up extending beyond 5 years of continuous treatment.

The following side effect frequency grid summarizes the adverse reactions observed during clinical development, categorized by how commonly they occur:

Very Common

May affect more than 1 in 10 patients

  • Vomiting
  • Low blood pressure (transient symptoms including dizziness, fatigue, or nausea shortly after injection)
  • Injection site reactions: redness, itching, inflammation, swelling, bruising, rash, hives (urticaria), pain

Common

May affect up to 1 in 10 patients

  • Nausea
  • Feeling faint or dizziness, including fainting (syncope)
  • Dizziness (vertigo)
  • Fatigue
  • Elevated alkaline phosphatase levels (detected through blood tests)

Injection site reactions are among the most frequently reported side effects and are an expected consequence of subcutaneous administration of a biologic drug. In clinical trials, these reactions were predominantly mild, typically appeared within minutes to hours of the injection, and resolved spontaneously without intervention. Rotating injection sites as recommended can help minimize the frequency and severity of local reactions.

The blood pressure lowering effect of Voxzogo is a pharmacological consequence of CNP receptor activation, which promotes vasodilation. In clinical trials, mean decreases in systolic blood pressure of approximately 5–10 mmHg were observed, with the nadir (lowest point) typically occurring within 15–30 minutes after injection. Blood pressure generally returned to baseline within 60–90 minutes. These effects were transient and self-limiting in the vast majority of patients. Symptomatic hypotension (causing dizziness, fatigue, or nausea) was more common in the initial weeks of treatment and tended to diminish over time with continued dosing.

The elevation of alkaline phosphatase (ALP) observed in some patients is considered a pharmacodynamic marker of increased bone turnover and growth plate activity, consistent with the mechanism of action of vosoritide. ALP elevations were generally mild, asymptomatic, and did not require treatment discontinuation. Regular monitoring of serum ALP levels is recommended as part of routine follow-up during Voxzogo treatment.

Throughout the clinical development program, no serious safety concerns, including no cases of anaphylaxis or severe allergic reactions requiring treatment discontinuation, have been reported. The long-term safety profile of Voxzogo has been reassuring, with no new or unexpected adverse events emerging with extended use beyond 5 years. Growth plate assessments performed during clinical trials showed no evidence of premature epiphyseal closure or abnormal bone development.

Reporting Side Effects

If you or your child experience any side effects while taking Voxzogo, including any effects not listed above, it is important to report them to your healthcare provider. You can also report suspected adverse reactions directly to your national pharmacovigilance authority (e.g., the FDA MedWatch program in the United States, or the Yellow Card Scheme in the United Kingdom). Reporting helps regulatory agencies continuously monitor the benefit-risk balance of medications.

How Should You Store Voxzogo?

Quick Answer: Store Voxzogo refrigerated at 2–8 °C in its original packaging, protected from light. Do not freeze. It can be stored at room temperature (below 30 °C) for up to 90 days. Once reconstituted, use within 3 hours.

Proper storage of Voxzogo is essential to maintain the stability and efficacy of the medication. As a biologic drug supplied as a lyophilized powder, vosoritide is sensitive to temperature extremes, light exposure, and moisture. The following storage guidelines should be strictly followed:

  • Refrigerated storage (preferred): Store Voxzogo in a refrigerator at 2–8 °C (36–46 °F). Keep the vials in their original carton to protect from light. Do not freeze the medication under any circumstances, as freezing can damage the protein structure and render the drug ineffective.
  • Room temperature storage (alternative): Voxzogo may be stored at room temperature below 30 °C (86 °F) for a single period of up to 90 days. Once removed from refrigeration, note the date on the carton and do not return the medication to the refrigerator. If the 90-day period expires before the printed expiry date, the medication should be discarded.
  • After reconstitution: Once the powder has been dissolved in the provided solvent, the solution must be used within 3 hours. Do not store the reconstituted solution for later use. If the solution appears cloudy, discolored, or contains visible particles, do not use it.
  • General precautions: Keep Voxzogo out of sight and reach of children. Do not use after the expiry date printed on the carton. The expiry date refers to the last day of the indicated month.

Unused or expired Voxzogo vials, needles, and syringes should be disposed of in a sharps container according to local regulations. Do not dispose of pharmaceutical waste in household trash. Ask your pharmacist about proper disposal procedures for unused medications to help protect the environment.

What Does Voxzogo Contain?

Quick Answer: The active ingredient in Voxzogo is vosoritide, available in three strengths (0.4 mg, 0.56 mg, and 1.2 mg). The powder is reconstituted with sterile water for injection before use. Inactive ingredients include citric acid, sodium citrate, trehalose dihydrate, mannitol, methionine, and polysorbat 80.

Active Ingredient

Vosoritide is the active pharmaceutical ingredient in Voxzogo. It is a 39-amino acid peptide analog of C-type natriuretic peptide (CNP), produced through recombinant DNA technology. Voxzogo is available in three vial strengths to accommodate the weight-based dosing regimen:

  • 0.4 mg vial: When reconstituted with 0.5 mL of solvent, yields a solution with a concentration of 0.8 mg/mL.
  • 0.56 mg vial: When reconstituted with 0.7 mL of solvent, yields a solution with a concentration of 0.8 mg/mL.
  • 1.2 mg vial: When reconstituted with 0.6 mL of solvent, yields a solution with a concentration of 2 mg/mL.

Inactive Ingredients (Excipients)

The powder formulation contains the following excipients that serve to stabilize the active ingredient and ensure proper reconstitution:

Voxzogo Excipients and Their Functions
Excipient E Number Function
Citric acid E 330 pH buffering agent
Sodium citrate E 331 pH buffering agent
Trehalose dihydrate Stabilizer (lyoprotectant)
Mannitol E 421 Bulking agent and tonicity modifier
Methionine Antioxidant (prevents oxidative degradation)
Polysorbat 80 E 433 Surfactant (prevents protein aggregation)

Packaging

Each Voxzogo carton contains 10 treatment sets, with each set comprising: one glass vial containing vosoritide powder (white to yellow), one pre-filled syringe with sterile water for injection (clear, colorless), one individually packaged single-use needle for reconstitution, and one individually packaged single-use dosing syringe. When the powder is properly reconstituted, the resulting solution should be clear, colorless to slightly yellow, and free from visible particles. If the solution does not meet these criteria, it should not be used.

Frequently Asked Questions About Voxzogo

Voxzogo (vosoritide) is a prescription medication used to treat achondroplasia, the most common form of short-limbed dwarfism, in patients aged 2 years and older whose growth plates are still open. Achondroplasia is caused by a mutation in the FGFR3 gene that suppresses bone growth. Voxzogo works by mimicking C-type natriuretic peptide (CNP), which counteracts the overactive FGFR3 signaling and promotes linear bone growth. It is the first and only pharmacological therapy specifically approved for this condition.

Voxzogo is given as a once-daily subcutaneous (under the skin) injection. The medication is supplied as a powder that must be reconstituted with sterile water for injection before use. After training from a healthcare professional, caregivers can administer the injection at home. The dose is based on body weight (15 micrograms per kilogram), and injections should be given at approximately the same time each day, rotating injection sites to prevent irritation. Recommended injection sites include the upper arms, thighs, abdomen, and buttocks.

The most common side effects are injection site reactions (redness, swelling, itching, pain, bruising, rash, and hives), vomiting, and transient low blood pressure that may cause dizziness, tiredness, or nausea shortly after injection. These effects are generally mild and resolve on their own within minutes to hours. Eating a light snack and drinking fluids approximately 30 minutes before the injection can help reduce blood pressure-related symptoms. Less common side effects include nausea, fainting, and elevated alkaline phosphatase levels.

In the pivotal Phase 3 clinical trial, children with achondroplasia who received Voxzogo for 52 weeks showed a mean increase in annualized growth velocity of 1.57 cm per year compared to placebo. This represented approximately a 50% improvement in growth rate. Long-term extension studies spanning up to 5 years have demonstrated that these growth benefits are sustained with continued treatment, with no evidence that the growth-promoting effect diminishes over time. However, Voxzogo does not cure achondroplasia and does not affect other aspects of the condition such as facial features or spinal changes.

Voxzogo should be stored in a refrigerator at 2–8 °C in its original packaging to protect from light. It must not be frozen. Alternatively, it can be stored at room temperature below 30 °C for up to 90 days, but it should not be returned to the refrigerator once removed. After reconstitution, the solution must be used within 3 hours. Record the date when removing from the refrigerator and discard if the 90-day room temperature storage period expires before the printed expiry date.

Voxzogo is only effective in patients whose growth plates (epiphyseal plates) are still open. Growth plates typically close during late adolescence, after which longitudinal bone growth ceases. Once the growth plates have fused, Voxzogo will not promote further bone growth, and treatment should be discontinued. Your physician will monitor growth plate status through imaging to determine when treatment should stop. In rare cases where adults still have open growth plates, treatment may theoretically continue, but this would require specialist evaluation.

References

  1. European Medicines Agency (EMA). Voxzogo (vosoritide) – Summary of Product Characteristics. Last updated 2025. Available at: www.ema.europa.eu
  2. U.S. Food and Drug Administration (FDA). Voxzogo (vosoritide) Prescribing Information. Last updated 2024. Available at: www.accessdata.fda.gov
  3. Savarirayan R, Tofts L, Irving M, et al. Once-daily, subcutaneous vosoritide therapy in children with achondroplasia: a randomised, double-blind, phase 3, placebo-controlled, multicentre trial. The Lancet. 2020;396(10252):684–692. doi:10.1016/S0140-6736(20)31541-5
  4. Savarirayan R, Tofts L, Irving M, 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. Genetics in Medicine. 2021;23(12):2443–2447. doi:10.1038/s41436-021-01287-7
  5. American Academy of Pediatrics (AAP). Health Supervision for Children with Achondroplasia – Clinical Report. Pediatrics. 2022;149(6):e2021060017. doi:10.1542/peds.2021-060017
  6. 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
  7. Legeai-Mallet L, Savarirayan R. Novel therapeutic approaches for the treatment of achondroplasia. Bone. 2020;141:115579. doi:10.1016/j.bone.2020.115579
  8. World Health Organization (WHO). International Classification of Diseases, 11th Revision (ICD-11). Achondroplasia: LD24.0. Geneva: WHO; 2024.

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