Last reviewed 2026-04-20 · How we verify

Elaprase (IDURSULFASE)

Elaprase works by replacing the deficient enzyme iduronate-2-sulfatase in the body.

Elaprase (idursulfase) is a small molecule enzyme replacement therapy developed by Shire, targeting Mucopolysaccharidosis II (MPS-II). It belongs to the class of hydrolytic lysosomal glycosaminoglycan-specific enzymes, which work by breaking down and replacing deficient enzymes in the body. Elaprase is FDA-approved since 2006 for the treatment of MPS-II, a rare genetic disorder. The commercial status of Elaprase is patented, and it is not yet available as a generic version. Key safety considerations include potential infusion reactions and the risk of antibody formation.

At a glance

Mechanism of action

Hunter syndrome (Mucopolysaccharidosis II, MPS II) is an X-linked recessive disease caused by insufficient levels of the lysosomal enzyme iduronate-2-sulfatase. This enzyme cleaves the terminal 2-O-sulfate moieties from the glycosaminoglycans (GAG) dermatan sulfate and heparan sulfate. Due to the missing or defective iduronate-2-sulfatase enzyme in patients with Hunter syndrome, GAG progressively accumulate in the lysosomes of variety of cells, leading to cellular engorgement, organomegaly, tissue destruction, and organ system dysfunction.ELAPRASE is intended to provide exogenous enzyme for uptake into cellular lysosomes. Mannose-6-phosphate (M6P) residues on the oligosaccharide chains allow binding of the enzyme to the M6P receptors on the cell surface, leading to cellular internalization of the enzyme, targeting to intracellular lysosomes and subsequent catabolism of accumulated GAG.

Approved indications

• Mucopolysaccharidosis, MPS-II

Boxed warnings

• WARNING: RISK OF ANAPHYLAXIS Life-threatening anaphylactic reactions have occurred in some patients during and up to 24 hours after ELAPRASE infusions. Anaphylaxis, presenting as respiratory distress, hypoxia, hypotension, urticaria and/or angioedema of throat or tongue have been reported to occur during and after ELAPRASE infusions, regardless of duration of the course of treatment. Closely observe patients during and after ELAPRASE administration and be prepared to manage anaphylaxis. Inform patients of the signs and symptoms of anaphylaxis and have them seek immediate medical care should symptoms occur. Patients with compromised respiratory function or acute respiratory disease may be at risk of serious acute exacerbation of their respiratory compromise due to hypersensitivity reactions and require additional monitoring [see Warnings and Precautions (5.1 , 5.3) and Adverse Reactions (6) ] . WARNING: RISK OF ANAPHYLAXIS See full prescribing information for complete boxed warning. Life-threatening anaphylactic reactions, presenting as respiratory distress, hypoxia, hypotension, urticaria and/or angioedema of throat or tongue have occurred in some patients during and up to 24 hours after ELAPRASE infusions. Closely observe patients during and after ELAPRASE administration and be prepared to manage anaphylaxis. Inform patients of the signs and symptoms of anaphylaxis and have them seek immediate medical care should symptoms occur. Patients with compromised respiratory function or acute respiratory disease may be at risk of serious acute exacerbation of their respiratory compromise due to hypersensitivity reactions and require additional monitoring. ( 5.1 , 5.3 , 6 )

Common side effects

• Hypersensitivity reactions
• Pyrexia
• Rash
• Headache
• Pruritus
• Urticaria
• Flushing
• Diarrhea
• Musculoskeletal Pain
• Bronchopneumonia/pneumonia
• Ear infection
• Cough

Key clinical trials

• PEARL (PrEnAtal Enzyme Replacement Therapy for Lysosomal Storage Disorders) (PHASE1)
• A Phase III Study of JR-141 in Patients With Mucopolysaccharidosis II (STARLIGHT) (PHASE3)
• An Extension Study to Assess the Long-term Safety and Efficacy of Hunterase (Idursulfase Beta) (PHASE3)
• A Study of ELAPRASE in Treatment-naïve Participants With Hunter Syndrome (Mucopolysaccharidosis [MPS] II) (PHASE4)
• Extension Study of Idursulfase-IT Along With Elaprase in Children and Adults With Hunter Syndrome and Cognitive Impairment (PHASE2,PHASE3)
• Long-term Evaluation on Height and Weight in Patients With MPS II Who Started Treatment at < 6 Years of Age (PHASE4)
• An Extension Study of HGT-HIT-045 Evaluating Long-Term Safety and Clinical Outcomes of Idursulfase-IT in Conjunction With Elaprase in Pediatric Participants With Hunter Syndrome and Cognitive Impairment (PHASE1,PHASE2)
• A Study to Determine the Efficacy and Safety of Tividenofusp Alfa (DNL310) vs Idursulfase in Pediatric and Young Adult Participants With Neuronopathic (nMPS II) or Non-Neuronopathic Mucopolysaccharidosis Type II (nnMPS II) (PHASE2,PHASE3)

Primary sources

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Competitive intelligence

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• Elaprase CI brief — competitive landscape report
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