XENPOZYME

What it is

Xenpozyme contains olipudase alfa, a recombinant human acid sphingomyelinase produced in a Chinese Hamster Ovary cell line by recombinant DNA technology. It is supplied as a powder for injection presented as a white to off-white lyophilised powder. Two strengths are registered on the ARTG: 4 mg and 20 mg vials. This medicinal product is subject to additional monitoring in Australia to allow quick identification of new safety information.

Approved indications —

Treatment of non-central nervous system manifestations of acid sphingomyelinase deficiency (ASMD) in paediatric and adult patients with type A/B (Niemann-Pick type A/B) or type B (Niemann-Pick type B).

Dosing overview

Xenpozyme treatment should be initiated and supervised by a physician experienced in the management of ASMD or other inherited metabolic disorders. Treatment with Xenpozyme should always be initiated via a dose escalation regimen followed by a maintenance dose. For adult patients, the recommended maintenance dosage is 3 mg/kg every 2 weeks following dose escalation from 0.1 mg/kg. For paediatric patients, the recommended maintenance dosage is 3 mg/kg every 2 weeks following dose escalation from 0.03 mg/kg. Xenpozyme must be reconstituted with sterile water for injections, diluted with sodium chloride 9 mg/mL (0.9%) solution for injection and then administered by intravenous infusion.

Key safety warnings

Infusion-associated reactions occurred in approximately 60% of patients treated with Xenpozyme in clinical studies and included hypersensitivity reactions and acute phase reactions. Infusion-associated reactions typically occurred between the time of infusion and up to 24 hours after infusion completion during dose escalation and maintenance phases. A limited number of paediatric patients experienced serious adverse events, including death, when receiving higher than recommended doses of Xenpozyme during dose escalation. Hypersensitivity reactions, including anaphylaxis, have been reported in Xenpozyme-treated patients; in clinical studies, hypersensitivity reactions occurred in 9 (22.5%) adult and 9 (45%) paediatric patients including one paediatric patient who experienced anaphylaxis. Transient transaminase elevations (ALT or AST) within 24 to 48 hours after infusions were reported during the dose escalation phase, and at the time of the next scheduled infusion, these elevated transaminase levels generally returned to the levels observed prior to Xenpozyme infusion. Xenpozyme is not expected to cross the blood-brain barrier or modulate the central nervous system manifestations of the disease.

Contraindications

Life-threatening hypersensitivity (anaphylactic reaction) to olipudase alfa or to any of the excipients.

PBS listing

Xenpozyme is not listed on the Pharmaceutical Benefits Scheme. The PBAC recommended against listing in July 2023 for the treatment of acid sphingomyelinase deficiency (ASMD).

Regulatory history

Xenpozyme olipudase alfa 20 mg powder for injection was first registered on the ARTG on 24 August 2023. The 4 mg strength was subsequently listed on 3 May 2024. The PBAC recommended against listing in July 2023.