Indication
ELAPRASE^® (idursulfase) is indicated for patients with Hunter syndrome (Mucopolysaccharidosis II, MPS II). ELAPRASE has been shown to improve walking capacity in these patients.

Important Safety Considerations

Risk of anaphylactic reactions: Life-threatening, anaphylactic reactions have been observed in some patients during ELAPRASE infusions. Therefore, appropriate medical support should be readily available when ELAPRASE is administered. Biphasic anaphylactic reactions have also been observed after ELAPRASE administration and patients who have experienced anaphylactic reactions may require prolonged observation. Patients with compromised respiratory function or acute respiratory disease may be at risk of serious acute exacerbation of their respiratory compromise due to infusion reactions, and require additional monitoring.

• Life-threatening anaphylactic reactions have been observed in some patients during ELAPRASE infusions. Reactions have included respiratory distress, hypoxia, hypotension, seizure, loss of consciousness, urticaria and/or angioedema of the throat and tongue. Biphasic anaphylactic reactions have also been reported to occur after administration of ELAPRASE approximately 24 hours after treatment and recovery from an initial anaphylactic reaction that occurred during ELAPRASE infusion. Interventions for biphasic reactions have included hospitalization, and treatment with epinephrine, inhaled beta-adrenergic agonists and corticosteroids.
• Patients with compromised respiratory function or acute respiratory disease may be at higher risk of life-threatening complications from infusion reactions. Consider delaying the ELAPRASE infusion in patients with concomitant acute respiratory and/or febrile illness.
• Because of the potential for severe infusion reactions, appropriate medical support should be readily available when ELAPRASE is administered. Because of the potential for biphasic anaphylactic reactions after ELAPRASE administration, patients who experience initial severe or refractory reactions may require prolonged observation. If a severe infusion reaction occurs, immediately suspend the infusion of ELAPRASE and initiate appropriate treatment. When severe infusion reactions occurred during clinical studies, subsequent infusions were managed by use of antihistamines and/or corticosteroids prior to or during infusions, a slower rate of ELAPRASE administration and/or early discontinuation of the ELAPRASE infusion if serious symptoms developed. With these measures, no patient discontinued treatment permanently due to an allergic reaction.
• In clinical studies, 51% of patients treated with ELAPRASE developed anti-idursulfase IgG antibodies. These patients had an increased incidence of infusion reactions, including allergic reactions. The relationship between the presence of anti-idursulfase antibodies and clinical efficacy outcomes is unknown.
• In clinical studies, the most common adverse events seen in patients treated with ELAPRASE were pyrexia (63%), headache (59%), and arthralgia (31%). The most common adverse reactions requiring intervention were infusion-related reactions including: headache, fever, cutaneous reactions (rash, pruritus, erythema and urticaria) and hypertension.
• The most frequent serious adverse events related to the use of ELAPRASE were hypoxic episodes. Other notable serious adverse reactions that occurred in ELAPRASE patients but not in placebo patients included one case each of cardiac arrhythmia, pulmonary embolism, cyanosis, respiratory failure, infection and arthralgia.