Vestronidase alfa

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Vestronidase alfa
Clinical data
Trade namesMepsevii
Other namesVestronidase alfa-vjbk
License data
Routes of
ATC code
Legal status
Legal status
  • US: ℞-only
  • EU: Rx-only
  • In general: ℞ (Prescription only)
CAS Number
Chemical and physical data
Molar mass72562.49 g·mol−1

Vestronidase alfa, sold under brand name Mepsevii, is a drug for the treatment of Sly syndrome.[1] It is a recombinant form of the human enzyme beta-glucuronidase. It was approved in the United States in November 2017, to treat children and adults with an inherited metabolic condition called mucopolysaccharidosis type VII (MPS VII), also known as Sly syndrome.[2][3] MPS VII is an extremely rare, progressive condition that affects most tissues and organs.[2]

The most common side effects after treatment with vestronidase alfa include infusion site reactions, diarrhea, rash (urticaria) and anaphylaxis (sudden, severe allergic reaction).[2][4]

The U.S. Food and Drug Administration (FDA) considers it to be a first-in-class medication.[5] It was approved for use in the European Union in August 2018.[4]

Medical uses[edit]

Mepsevii is indicated for the treatment of non-neurological manifestations of Mucopolysaccharidosis VII (MPS VII; Sly syndrome).[4][6]


The safety and efficacy of vestronidase alfa were established in a clinical trial and expanded access protocols enrolling a total of 23 participants ranging from five months to 25 years of age.[2] Participants received treatment with vestronidase alfa at doses up to 4 mg/kg once every two weeks for up to 164 weeks.[2] Efficacy was primarily assessed via the six-minute walk test in ten participants who could perform the test.[2] After 24 weeks of treatment, the mean difference in distance walked relative to placebo was 18 meters.[2] Additional follow-up for up to 120 weeks suggested continued improvement in three participants and stabilization in the others.[2] Two participants in the vestronidase alfa development program experienced marked improvement in pulmonary function.[2] Overall, the results observed would not have been anticipated in the absence of treatment.[2] The effect of vestronidase alfa on the central nervous system manifestations of MPS VII has not been determined.[2]

The FDA approved vestronidase alfa-vjbk based primarily on evidence from one clinical trial (NCT02230566) of 12 participants with mucopolysaccharidosis VII. The trial was conducted at four sites in the United States.[3]

The benefit and side effects of vestronidase alfa were based primarily on one trial.[3] Participants were randomly assigned to four groups.[3] Three groups of participants received placebo treatment before starting vestronidase alfa treatment and one group received vestronidase alfa only.[3] vestronidase alfa or placebo were given once every two weeks as intravenous (IV) infusions.[3] Neither participants nor healthcare providers knew which treatment was given until after the trial was competed.[3]

The benefit of 24 weeks of vestronidase alfa treatment was primarily evaluated by the 6-minute walking test (6MWT) and compared to placebo treatment in ten participants who could perform the test.[3] The 6MWT measured the distance a patient could walk on a flat surface in 6 minutes.[3] An additional follow-up using 6MWT was done for up to 120 weeks.[3]

The application for vestronidase alfa was granted fast track designation, orphan drug designation, and a rare pediatric disease priority review voucher.[2] This was the twelfth rare pediatric disease priority review voucher issued.[2]

The U.S. Food and Drug Administration (FDA) granted approval of Mepsevii to Ultragenyx Pharmaceutical, Inc,[2] and required the manufacturer to conduct a post-marketing study to evaluate the long-term safety of the product.[2]


  1. ^ McCafferty EH, Scott LJ (April 2019). "Vestronidase Alfa: A Review in Mucopolysaccharidosis VII". BioDrugs. 33 (2): 233–240. doi:10.1007/s40259-019-00344-7. PMC 6469592. PMID 30848434.
  2. ^ a b c d e f g h i j k l m n o "FDA approves treatment for rare genetic enzyme disorder" (Press release). U.S. Food and Drug Administration (FDA). 15 November 2017. Archived from the original on 10 December 2019. Retrieved 9 December 2019. Public Domain This article incorporates text from this source, which is in the public domain.
  3. ^ a b c d e f g h i j "Drug Trial Snapshot: Mepsevii". U.S. Food and Drug Administration (FDA). 4 December 2017. Archived from the original on 10 December 2019. Retrieved 9 December 2019. Public Domain This article incorporates text from this source, which is in the public domain.
  4. ^ a b c "Mepsevii EPAR". European Medicines Agency (EMA). Retrieved 28 February 2020. Text was copied from this source which is © European Medicines Agency. Reproduction is authorized provided the source is acknowledged.
  5. ^ New Drug Therapy Approvals 2017 (PDF). U.S. Food and Drug Administration (FDA) (Report). January 2018. Retrieved 16 September 2020.
  6. ^ "Mepsevii- vestronidase alfa injection". DailyMed. 19 November 2017. Retrieved 5 August 2020.

External links[edit]

  • "Vestronidase alfa". Drug Information Portal. U.S. National Library of Medicine.
  • Clinical trial number NCT02230566 for "A Phase 3 Study of UX003 Recombinant Human Betaglucuronidase (rhGUS) Enzyme Replacement Therapy in Patients With Mucopolysaccharidosis Type 7 (MPS 7)" at