Alglucosidase Alfa

The presence of IgG antibodies has been observed within 3 months from the onset of therapy in the majority of patients. High and sustained IgG antibody titers may result in reduced efficacy of alglucosidase alfa (eg, loss of motor function, ventilator dependence, death). Regularly monitor all patients for development of IgG antibodies; consider testing for IgG titers in patients who develop hypersensitivity reactions, other immune-mediated reactions, or loss of clinical response. Patients with reduced clinical response may also be tested for inhibitory antibody activity.

[U.S. Boxed Warning]: Life-threatening anaphylactic reactions and severe hypersensitivity reactions, some of which were IgE mediated, may occur; immediate medical support should be readily available. Reactions may occur during and up to 3 hours after infusion. Patients who develop IgE antibodies to alglucosidase alfa may be at a higher risk; monitor these patients closely during administration. Consider testing for IgG titers in patients who develop allergic reactions; may also test for IgE antibodies or other mediators of anaphylaxis. Consider risks/benefits of readministration following an anaphylactic or severe allergic reaction; some patients have been rechallenged under close clinical supervision; appropriate resuscitation measures should be available.

[U.S. Boxed Warning]: Severe immune-mediated reactions (eg, necrotizing skin lesions, nephrotic syndrome secondary to membranous glomerulonephritis, proteinuria, inflammatory arthropathy) may occur; immediate medical support should be readily available. Reactions have occurred up to 3 years after initiation of therapy. Monitor urinalysis periodically. Monitor for immune-mediated reaction development. Consider testing for IgG titers in patients who develop immune-mediated reactions; may also test for IgE antibodies. Consider risks/benefits of readministration; some patients have been successfully rechallenged under close clinical supervision.

Infusion-related reactions are common and may occur during and up to 2 hours after infusion. Appropriate medical support for the management of infusion reactions should be readily available. Discontinue immediately for severe hypersensitivity or anaphylactic reaction; mild to moderate reactions may be managed by reducing the infusion rate and/or administering antihistamines and/or antipyretics. Use caution with subsequent infusions; infusion reactions have occurred despite premedication with antihistamines, antipyretics, and/or corticosteroids. Patients with acute underlying illness are at greater risk for infusion reactions, including cardiorespiratory failure; monitor closely during infusion. Although less common, delayed-onset (within 48 hours after administration) infusion reactions have also occurred. Disease-related concerns:

[U.S. Boxed Warning]: Use with caution in patients with compromised cardiac function; risk of acute cardiorespiratory failure secondary to infusion-related reactions or fluid overload may be increased. Additional monitoring is warranted. Cardiorespiratory failure has been observed in patients with cardiac hypertrophy up to 72 hours after infusion; arrhythmias have also been observed in patients with cardiac hypertrophy.

[U.S. Boxed Warning]: Use with caution in patients with compromised respiratory function; risk of acute cardiorespiratory failure secondary to infusion-related reactions or fluid overload may be increased. Additional monitoring is warranted.

Patients with sepsis may be at increased risk for cardiorespiratory failure during infusions. Dosage form specific issues:

Some dosage forms may contain polysorbate 80 (also known as Tweens). Hypersensitivity reactions, usually a delayed reaction, have been reported following exposure to pharmaceutical products containing polysorbate 80 in certain individuals (Isaksson, 2002; Lucente 2000; Shelley, 1995). Thrombocytopenia, ascites, pulmonary deterioration, and renal and hepatic failure have been reported in premature neonates after receiving parenteral products containing polysorbate 80 (Alade, 1986; CDC, 1984). See manufacturer’s labeling. Other warnings/precautions:

Use of general anesthesia for catheter placement for alglucosidase alfa infusions may be complicated by the presence of cardiac and skeletal (including respiratory) muscle weakness in patients with Pompe disease; use general anesthesia with caution.

A registry has been created to monitor therapeutic responses and adverse effects during long-term treatment; patients should be encouraged to register (www.pomperegistry.com or 1-800-745-4447).