Vestronidase Alfa (Mepsevii)

Section: Injections
Effective Date: February 01, 2020
Revised Date: January 28, 2020


Vestronidase alpha-vjbk (Mepsevii) is a recombinant human lysosomal beta glucuronidase enzyme replacement indicated in pediatric and adult individuals for the treatment of Mucopolysaccharidosis VII (MPS VII, Sly syndrome).

MPS VII is caused by pathogenic mutations in the GUSB gene. The GUSB gene is responsible for producing an enzyme called beta-glucuronidase which is involved in the breakdown of large molecules called glycosaminoglycans (GAGs).


Coverage is subject to the specific terms of the member's benefit plan.

Federal Employee Program members (FEP) should check with their Retail Pharmacy Program to determine if prior approval is required by calling the Retail Pharmacy Program at 1-800-624-5060 (TTY: 1-800-624-5077). FEP members can also obtain the list through the website.

Vestronidase alpha (Mepsevii) may be considered medically necessary in infant, pediatric and adult individuals' age five (5) months and older that meets All of the following:

  • Diagnosis of MPS VII (Sly syndrome); and
  • ANY of the following:
    • Molecular genetic confirmation of pathogenic mutations in the GUSB gene; or
    • Clinical signs and symptoms of MPS VII (may include but are not limited to skeletal abnormalities shown on x-ray, short stature, macrocephaly, hepatosplenomegaly, history of inguinal or umbilical hernia, decreased pediatric quality of life score, decreased forced vital capacity (FVC) or impaired six minute walk test appropriate for age) and the following abnormal lab values:
      • Decreased level of beta-glucuronidase activity in blood; and
      • Increased level of urinary GAGs.

Continuation of therapy after twelve (12) months will be considered medically necessary for individuals diagnosed with MPS VII when all of the following criteria are met:

  • Documentation of decreased urinary GAG level; and
  • Documentation of improvement of clinical signs and symptoms such as but not limited to improvement in the six minute walk test, pediatric quality of life or forced vital capacity (FVC).

The use of vestronidase alpha (Mepsevii) for any other indication is considered experimental/investigational and therefore, non-covered. There is a lack of clinical data to support its safety and efficacy in other conditions

Procedure Codes


NOTE: In addition to the above criteria, product specific dosage and/or frequency limits may apply in accordance with the U.S. Food and Drug Administration (FDA)-approved product prescribing information, national compendia, Centers for Medicare and Medicaid Services (CMS) and other peer reviewed resources or evidence-based guidelines. Blue Cross Blue Shield of North Dakota may deny, in full or in part, reimbursement for utilization that does not fall within the applicable dosage and/or frequency limits.

Diagnosis Codes


Professional Statements and Societal Positions Guidelines