MEPSEVII
Clinical safety rating: caution
Comprehensive clinical and safety monograph for MEPSEVII (MEPSEVII).
MEPSEVII (vestronidase alfa) is a recombinant form of human beta-glucuronidase that hydrolyzes accumulated glycosaminoglycans (GAGs) in lysosomes, restoring enzymatic activity in patients with Mucopolysaccharidosis VII (Sly syndrome).
| Metabolism | Vestronidase alfa is a protein; expected to be degraded into small peptides and amino acids via general protein catabolism pathways. |
| Excretion | Renal: negligible; primarily catabolized via peptide hydrolysis to amino acids, which are recycled or excreted in urine as metabolites. |
| Half-life | Terminal elimination half-life: 9.4 hours (range 6.3–16.6 hours) in patients with mucopolysaccharidosis VII; supports weekly intravenous dosing. |
| Protein binding | Negligible (<1%); not bound to plasma proteins. |
| Volume of Distribution | Volume of distribution (Vd): approximately 0.3 L/kg (range 0.2–0.5 L/kg), consistent with limited extravascular distribution. |
| Bioavailability | Bioavailability: 100% intravenous; not administered via other routes. |
| Onset of Action | Intravenous: reduction in urinary glycosaminoglycan (GAG) levels observed within 4 weeks of initiating weekly infusion. |
| Duration of Action | Sustained reduction in urinary GAG levels over 48 weeks of treatment; clinical effects on hepatosplenomegaly and other manifestations persist with continued weekly dosing. |
| Molecular Weight | 130000 |
1 mg/kg administered intravenously once weekly over 4 hours.
| Dosage form | INJECTABLE |
| Renal impairment | No dose adjustment required for renal impairment; safety and efficacy not established in severe renal impairment. |
| Liver impairment | No dose adjustment required for hepatic impairment. |
| Pediatric use | 1 mg/kg administered intravenously once weekly over 4 hours; safety and efficacy established in pediatric patients. |
| Geriatric use | No specific dose adjustment recommended; use with caution due to limited data in elderly patients. |
| 1st trimester | No adequate human data; animal studies show no malformations; use only if clearly needed. |
| 2nd trimester | No adequate human data; animal studies show no fetal harm; consider risk-benefit. |
| 3rd trimester | No adequate human data; may be used if indicated; caution with preterm labor due to potential for placental abruption with rhodiola extract component? |
Clinical note
Comprehensive clinical and safety monograph for MEPSEVII (MEPSEVII).
| Placental transfer | Not studied in humans; due to high molecular weight (~130 kDa), placental transfer is expected to be minimal. |
| Breastfeeding | Excretion into human milk unknown; due to high molecular weight and likely degradation in infant GI tract, risk to breastfed infant is considered low. However, caution is advised. |
■ FDA Black Box Warning
There is no FDA black box warning for MEPSEVII.
| Serious Effects |
Hypersensitivity to mecasermin or any component of the formulation
| Precautions | Risk of severe hypersensitivity reactions including anaphylaxis, Infusion-associated reactions (fever, chills, rash, urticaria), Acute respiratory distress in patients with underlying respiratory compromise |
| Food/Dietary | No specific food interactions are known for MEPSEVII. However, as with any IV therapy, maintain a normal diet and hydration unless instructed otherwise by the physician. |
| Clinical Pearls |
Loading safety data…
| Lactation Rating |
| L3 (Moderately Safe) |
| Teratogenic Risk | Insufficient human data; animal studies show no teratogenic effects at doses up to 10 times the human dose. Fetal risk cannot be excluded. Use only if maternal benefit outweighs potential fetal risk. |
| Fetal Monitoring | Monitor maternal liver function tests, renal function, and signs of hypersensitivity reactions during pregnancy. Fetal ultrasound for growth and anatomy if exposure occurs. |
| Fertility Effects | No animal studies on fertility; no human data available. Potential for immunogenicity to interfere with endogenous enzymes, theoretical risk to fertility. |
| MEPSEVII (vestronidase alfa) is a recombinant human beta-glucuronidase used for mucopolysaccharidosis VII (Sly syndrome). Administer intravenously over 4 hours. Premedicate with antihistamines and antipyretics 30-60 minutes prior to infusion due to risk of hypersensitivity reactions. Monitor for infusion-associated reactions (IARs) during and after infusion. Do not administer as bolus. Use with caution in patients with underlying airway compromise. Not studied in patients with severe renal impairment. |
| Patient Advice | MEPSEVII is an enzyme replacement therapy for mucopolysaccharidosis VII (Sly syndrome). · It is given as an intravenous infusion every 2 weeks. · You may experience infusion reactions such as flushing, rash, fever, or difficulty breathing; report these immediately. · Premedication with antihistamines and fever-reducing medicine will be given before each infusion. · Regular monitoring of your symptoms and organ function is necessary. · Inform your healthcare provider of any other medications or supplements you are taking. · Avoid consuming large meals immediately before infusion to reduce risk of nausea. |