How MEPSEVII® (vestronidase alfa-vjbk) may work

How MEPSEVII® (vestronidase alfa-vjbk) may work

MEPSEVII is a formulation of the GUS enzyme

It was shown in animal studies to regularly replace the missing GUS enzyme.

How MEPSEVII may work

MEPSEVII may help to restore cell function by replacing an enzyme that is missing in people with MPS VII. This process of replacing the missing or deficient enzyme is called enzyme replacement therapy (ERT).


All patients treated with MEPSEVII experienced a reduction in urinary GAGs, which was sustained with continued treatment

MEPSEVII is used to treat children and adults with Mucopolysaccharidosis VII (MPS VII, Sly syndrome). The effect of MEPSEVII on the central nervous system (brain and spinal cord) symptoms of MPS VII has not been determined.
What is the most important information I should know about MEPSEVII?
  • A severe allergic reaction called anaphylaxis has occurred with MEPSEVII treatment, as early as the first dose.
  • Your healthcare provider will monitor you closely for symptoms of an allergic reaction while you are receiving MEPSEVII and for 60 minutes after your infusion.
  • Your healthcare provider will immediately discontinue the MEPSEVII infusion if you experience anaphylaxis.
  • Your healthcare provider should talk to you about the signs and symptoms of anaphylaxis and about getting immediate medical treatment if you have symptoms.
What are the possible side effects of MEPSEVII?
  • The most common side effects of MEPSEVII are:
    • Leakage of MEPSEVII into the surrounding tissue during infusion
    • Diarrhea
    • Rash
    • Severe allergic reaction (anaphylaxis)
    • Infusion site swelling
    • Swelling around the infusion site
    • Severe itching of the skin
  • One patient experienced a seizure during a fever while taking MEPSEVII.
Before receiving MEPSEVII, tell your healthcare provider about all of your medical conditions, including if you:
  • are pregnant, think you may be pregnant, or plan to become pregnant. There is not enough experience to know if MEPSEVII may harm your unborn baby.
  • are breastfeeding or plan to breastfeed. There is not enough experience to know if MEPSEVII passes into your breast milk. Talk with your healthcare provider about the best way to feed your baby while you receive MEPSEVII.

These are not all the possible side effects of MEPSEVII. Call your healthcare provider for medical advice about side effects.

You may report side effects to the FDA at (800) FDA-1088 or You may also report side effects to Ultragenyx at 1-888-756-8657.

Please see full Prescribing Information for additional Important Safety Information including serious side effects.