idursulfase: clinical use

Prescribing considerations

• Treatment should be supervised by clinicians experienced in Hunter syndrome or inherited metabolic disease.
• Assess airway and cardiorespiratory risk before infusion; consider postponement during acute febrile respiratory illness.
• Ensure trained staff, observation and resuscitation facilities are available because anaphylaxis can occur even after years of treatment.
• Record the product name and batch number for biological traceability.

Contraindications and cautions

• Severe or life-threatening hypersensitivity to idursulfase or an excipient when the reaction cannot be controlled.
• Use particular caution with severe obstructive airway disease and when considering re-exposure after anaphylaxis.

Monitoring

• Monitor during and after infusion for hypersensitivity, respiratory compromise and blood-pressure changes.
• Follow relevant functional, respiratory, cardiac, organ-volume and urinary glycosaminoglycan outcomes.
• Consider anti-idursulfase and neutralising antibodies when reactions or a reduced pharmacodynamic response raise concern.
• Complete deletion or large-rearrangement genotypes carry greater immunogenicity and infusion-reaction risk.

Clinical pharmacology

Recombinant human iduronate-2-sulfatase binds mannose-6-phosphate receptors, enters lysosomes and promotes degradation of dermatan sulfate and heparan sulfate. It is degraded by protein hydrolysis to peptides and amino acids; cytochrome P450 metabolism is not expected.

Formulation and product differences

• The product is a preservative-free, single-use concentrate requiring dilution with sodium chloride infusion solution.
• Use an in-line filter and do not infuse through the same tubing as other medicines.
• The concentrate contains sodium and must not be frozen or shaken.

Solution for infusion

Route: Intravenous

Strengths: 2 mg/mL