Successful desensitization to alglucosidase alfa in a very young infant with Pompe disease

Enzyme replacement therapy (ERT) with alglucosidase alfa markedly improves outcomes in infantile-onset Pompe disease, yet hypersensitivity reactions may interrupt treatment and require desensitization. We report a very young infant in whom ERT was successfully maintained after allergic reactions through a structured desensitization protocol.

A 3-month-old male with infantile-onset Pompe disease developed generalized urticaria during the seventh alglucosidase alfa infusion despite premedication and infusion rate adjustment. Skin testing was not feasible due to age. After obtaining informed consent, desensitization was initiated in a specialized setting. Initial three- and four-bag protocols were unsuccessful because of recurrent urticaria. A final five-bag, sixteen-dose protocol using enzyme concentrations from 0.0005 to 1 mg/mL enabled the full therapeutic dose to be administered safely. The same regimen was subsequently applied in following infusions without recurrence of symptoms.

This case demonstrates that desensitization can be effectively implemented even in very young infants with Pompe disease who experience hypersensitivity during ERT. A carefully designed protocol and close clinical monitoring allow continuation of this life-saving therapy when no alternative treatment exists.