Alglucosidase alfa, sold under the brand name Myozyme among others, is an enzyme replacement therapy (ERT) orphan drug for treatment of Pompe disease (Glycogen storage disease type II), a rare lysosomal storage disorder (LSD).Chemically speaking, the drug is an analog of the enzyme that is deficient in patients affected by Pompe disease, alpha-glucosidase. It is the first drug available to treat this disease. It was approved for medical use in the United States in April 2006, as Myozyme and in May 2010, as Lumizyme.