Table 3.

Desensitization principles for infants and young children on alglucosidase alfa.

Evaluate the immune status If IgE is positive, do not pre-treat with antihistamines, antipyretics or steroids as this may mask primary manifestations of an immune reaction leading to anaphylaxis If IgE is negative, prophylactic premedication may be used, if blood pressure is low—encourage fluid intake based on volume status

Minimize volume for infants with cardiomyopathy

Introduce 1/2 the standard dose weekly until tolerated

Prepare micro dilutions of alglucosidase alfa and cautiously infuse, adjusting the dose/rate based on the patients clinical manifestations and tolerance

If a reaction occurs Monitor the patient carefully and record vital signs, if symptoms progress, stop the infusion and administer anaphylaxis medications as needed. Restart IV at last “safe” dose rate for 15–30 min, then resume planned infusion. When resuming infusion observe carefully for early onset of recurrent symptoms. If reaction symptoms/signs are recurrent and mild: slow down the infusion to the last safe rate before developing the reaction, if symptoms persist or become more severe stop the infusion immediately and treat the reaction according to the clinical findings. Carefully document at the time of the reaction: all symptoms/signs, in addition to the infusion number and dose/rate at which symptoms occurred

Reassess the dose and rate of the micro-dilution used, modifying the dose/rate as indicated based on patients’ response to each infusion before preparing the next infusion—consider lengthening the “safe rate” duration and making step-up rates more gradual when needed.

After 2 successive infusions have been administered successfully at 1/2 the standard dose weekly; recalculate to deliver 3/4 of the dose, every 10 days; when tolerated, administer the full dose at a modified rate scheduled to be given every 2 weeks until the standard recommended rate is achieved. Micro dilution calculations should be made in mcg/kg/h or mg/kg/h.