The FDA has approved Mepsevii (vestronidase alfa-vjbk) to treat pediatric and adult patients with an inherited metabolic condition called mucopolysaccharidosis type VII (MPS VII), also known as Sly syndrome, a rare disorder that causes enlarged liver and spleen, skeletal abnormalities, short stature, lung infections and a variety of other complications.

Indications: Mepsevii is recombinant human lysosomal beta glucuronidase, a type of enzyme replacement therapy. The drug is intended for pediatric and adult patients with mucopolysaccharidosis type VII (MPS VII), also known as Sly syndrome.

Dosage and administration: The recommended dosage is 4 mg/kg administered every 2 weeks as an intravenous infusion. Premedication with a non-sedating antihistamine with or without an anti-pyretic is recommended 30 to 60 minutes prior to the start of the infusion. Administer the infusion over approximately 4 hours. In the first hour of infusion, infuse 2.5% of the total volume. After the first hour, the rate can be increased to infuse the remainder of the volume over 3 hours as tolerated.

Adverse reactions: The most common adverse reactions are infusion site extravasation, diarrhea, rash, anaphylaxis, infusion site swelling, peripheral swelling and pruritus.