Preparation instructions for MEPSEVII™ (vestronidase alfa-vjbk)

This product should be prepared and administered under the supervision of a health care professional with the capability to manage anaphylaxis. Prepare and use MEPSEVII according to the following steps using aseptic technique:

  1. Determine the number of vials to be diluted based on the patient’s actual weight and the recommended dose of 4 mg/kg, using the following calculations:

  2. Round to the next whole vial and remove the required number of vials from the refrigerator to allow them to reach room temperature. Do not heat, microwave, or shake vials.

  3. The final solution will be a 1:1 dilution of MEPSEVII with 0.9% Sodium Chloride Injection, USP. More than 1:1 dilution may be used if the patient can tolerate additional infusion volume, taking into consideration cardiac function and fluid status.

  4. For a 1:1 dilution, prepare the solution at room temperature, as follows:

    1. Select an empty infusion bag, sized upon the total volume of the final solution.

    2. Prior to withdrawing MEPSEVII from the vial, visually inspect the solution for particulate matter and discoloration. Because this is a protein solution, slight flocculation (thin translucent fibers) may occur. The MEPSEVII solution should be colorless to slightly yellow. Discard if the solution is discolored or if there is particulate matter in the solution.

    3. Slowly withdraw the volume of the calculated MEPSEVII dose from the appropriate number of vials (step 2) using caution to avoid excessive agitation and any air or frothing. Use a sufficiently large needle (18 gauge) to minimize bubbles in the solution.

    4. Slowly add MEPSEVII to the infusion bag using care to avoid agitation, ensuring liquid-to-liquid contact without generating bubbles or turbulence.

    5. Add 0.9% Sodium Chloride Injection, USP equal to the volume of MEPSEVII to the infusion bag.

    6. Gently rock the infusion bag to ensure proper distribution of MEPSEVII. Do not shake the solution.

To help find the correct dosage of MEPSEVII to administer to your patients, use the MEPSEVII Dosing Chart

MEPSEVII is a recombinant human lysosomal beta glucuronidase indicated in pediatric and adult patients for the treatment of Mucopolysaccharidosis VII (MPS VII, Sly syndrome).

Limitations of Use
The effect of MEPSEVII on the central nervous system manifestations of MPS VII has not been determined.



  • Anaphylaxis has occurred with MEPSEVII administration, as early as the first dose, therefore appropriate medical support should be readily available when MEPSEVII is administered.
  • Closely observe patients during and for 60 minutes after MEPSEVII infusion.
  • Immediately discontinue the MEPSEVII infusion if the patient experiences anaphylaxis.
  • Anaphylaxis to MEPSEVII was reported in 2 of 20 patients in the clinical program. The two patients with anaphylaxis to MEPSEVII during the clinical trials had one occurrence each and tolerated subsequent infusions of MEPSEVII, without recurrence.
  • Consider the risks and benefits of re-administering MEPSEVII following anaphylaxis.
  • Manifestations included respiratory distress, cyanosis, decreased oxygen saturation, and hypotension.
  • Prior to discharge, inform patients of the signs and symptoms of anaphylaxis and instruct them to seek immediate medical care if symptoms occur.

Adverse Reactions

  • In a clinical trial, the most common adverse reactions occurring with MEPSEVII treatment included infusion site extravasation, diarrhea, rash, anaphylaxis, infusion site swelling, peripheral swelling, and pruritus.
  • One patient experienced a febrile convulsion during MEPSEVII treatment. The patient subsequently was re-challenged without recurrence and continued on treatment.

Use in Specific Populations

  • There are no available data on MEPSEVII use in pregnant women to determine a drug-associated risk of adverse developmental outcomes.
  • There are no data on the presence of MEPSEVII in either human or animal milk, the effects on the breastfed infant, or the effects on milk production. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for MEPSEVII and any potential adverse effects on the breastfed infant from MEPSEVII or from the underlying maternal condition.

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, including the BOXED WARNING, for a complete discussion of the risks associated with MEPSEVII.