Skip to main content

Vestronidase Alfa

Medically reviewed by Last updated on Oct 22, 2020.


(ves TRON i dase AL fa)

Index Terms

  • Recombinant Human Beta-Glucuronidase (rhGUS)
  • Vestronidase Alfa-vjbk

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Solution, Intravenous [preservative free]:

Mepsevii: vestronidase alfa-vjbk 10 mg/5 mL (5 mL)

Brand Names: U.S.

  • Mepsevii

Pharmacologic Category

  • Enzyme


Vestronidase alfa is a recombinant human beta-glucuronidase (GUS), which provides exogenous GUS enzyme for uptake into cellular lysosomes. Mannose-6-phosphate (M6P) residues on the oligosaccharide chains allow binding of the enzyme to cell surface receptors, leading to cellular uptake of the enzyme, targeting to lysosomes and subsequent catabolism of accumulated glycosaminoglycans (GAGs) in affected tissues.


Vd,ss: 260 ± 130 mL/kg (range: 97 to 598 mL/kg)


Proteolytic degradation into small peptides and amino acids

Half-Life Elimination

155 ± 37 minutes (range: 51 to 213 minutes)

Use: Labeled Indications

Mucopolysaccharidosis VII: Treatment of mucopolysaccharidosis VII (MPS VII, Sly syndrome).

Limitations of use: The effect of vestronidase alfa on the CNS manifestations of MPS VII has not been determined.


There are no contraindications listed in the manufacturer's labeling.

Dosing: Adult

Note: Premedicate with nonsedating antihistamines with/without antipyretics 30 to 60 minutes prior to the start of the infusion.

Mucopolysaccharidosis VII: IV: 4 mg/kg every 2 weeks

Dosing: Geriatric

Refer to adult dosing.

Dosing: Pediatric

Mucopolysaccharidosis VII (MPS VII, Sly syndrome): Note: Premedicate with nonsedating antihistamines with or without antipyretics 30 to 60 minutes prior to the start of the infusion.

Infants, Children, and Adolescents: IV: 4 mg/kg/dose every 2 weeks


Calculate dose (rounding to nearest whole vial) then remove vial(s) from refrigerator and allow to reach room temperature; do not heat, microwave, or shake vials. Solution in vials should be colorless to slightly yellow; discard if solution is discolored or contains particulate matter. Withdraw calculated dose (volume) from vials carefully; avoid excessive agitation and any air or frothing; use an 18-gauge needle to minimize bubbles in the solution. Slowly add to empty infusion bag to avoid agitation and generation of bubbles or turbulence. Dilute to a final 1:1 solution with NS; more than a 1:1 dilution may be used in patients who can tolerate additional volume. To ensure adequate distribution; gently rock the infusion bag without shaking the solution. Discard any unused product.


IV: Infuse IV over ~4 hours; infuse the first 2.5% of total volume over the first hour (accounting for any dead space in IV line); after the first hour, increase infusion rate (as tolerated) to complete infusion over the next 3 hours. Administer using an infusion set with an in-line low protein-binding 0.2 micron filter. Do not flush the line to avoid a rapid bolus of infused enzyme; due to the low infusion rate, additional NS may be added through a separate line (piggyback or Y tube) to maintain sufficient IV flow to prevent clotting or line blockage. Do not infuse other products in same IV line. Discontinue the infusion immediately if severe reaction occurs, including anaphylaxis. Observe patient during, and for 60 minutes following infusion.

May be an irritant; ensure proper needle or catheter placement prior to and during IV infusion. Avoid extravasation.


Store under refrigeration at 2°C to 8°C (36°F to 46°F). Do not freeze or shake. Protect from light. Following dilution use immediately; if this is not possible, the diluted solution may be stored up to 36 hours under refrigeration followed by up to 6 hours at room temperature ≤25°C (77°F). Infusion should be completed within 42 hours from time of dilution.

Drug Interactions

There are no known significant interactions.

Adverse Reactions

The following adverse drug reactions and incidences are derived from product labeling unless otherwise specified.


Dermatologic: Skin rash (≤25%)

Gastrointestinal: Diarrhea (≤25%)

Hypersensitivity: Anaphylaxis (10% to 17%)

Immunologic: Antibody development (≤78%; neutralizing: ≤56%)

1% to 10%:

Cardiovascular: Peripheral edema (≤8%)

Dermatologic: Pruritus (≤8%)

Local: Swelling at injection site (≤8%)

Frequency not defined: Miscellaneous: Febrile seizures

ALERT: U.S. Boxed Warning


Anaphylaxis has occurred with vestronidase alfa administration, as early as the first dose, therefore appropriate medical support should be readily available when administered. Closely observe patients during and for 60 minutes after vestronidase alfa infusion. Immediately discontinue the infusion if the patient experiences anaphylaxis.


Concerns related to adverse effects:

• Extravasation: Infusion site extravasation has been reported; infusion site swelling has also occurred.

• Hypersensitivity/anaphylactoid reactions: [US Boxed Warning]: Anaphylaxis has occurred with administration, as early as the first dose, therefore appropriate medical support should be readily available when administered. Manifestations included respiratory distress, cyanosis, decreased oxygen saturation, and hypotension. Closely observe patients during and for 60 minutes after infusion. Immediately discontinue the infusion if the patient experiences anaphylaxis. Consider the risks and benefits of re-administering vestronidase alfa following anaphylaxis; in clinical trials, patients experiencing anaphylaxis were able to tolerate subsequent infusions without recurrence of anaphylaxis.

Monitoring Parameters

Monitor for infusion/hypersensitivity reactions. Monitor infusion site.

Pregnancy Considerations

Adverse events were not observed in animal reproduction studies.

Patient Education

What is this drug used for?

• It is used to treat mucopolysaccharidosis VII.

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

• Blue/gray skin discoloration

• Nail discoloration

• Severe dizziness

• Passing out

• Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.

Note: This is not a comprehensive list of all side effects. Talk to your doctor if you have questions.

Consumer Information Use and Disclaimer: This information should not be used to decide whether or not to take this medicine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a limited summary of general information about the medicine's uses from the patient education leaflet and is not intended to be comprehensive. This limited summary does NOT include all information available about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not intended to provide medical advice, diagnosis or treatment and does not replace information you receive from the healthcare provider. For a more detailed summary of information about the risks and benefits of using this medicine, please speak with your healthcare provider and review the entire patient education leaflet.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.