indication

For the treatment of Pompe disease (GAA deficiency) in infants and pediatric patients.

pharmacology

Pompe disease (glycogen storage disease type II, GSD II, glycogenosis type II, acid maltase deficiency) is an inherited disorder of glycogen metabolism caused by the absence or marked deficiency of the lysosomal enzyme GAA. In the infantile-onset form, Pompe disease results in intralysosomal accumulation of glycogen in various tissues, particularly cardiac and skeletal muscles, and hepatic tissues, leading to the development of cardiomyopathy, progressive muscle weakness, and impairment of respiratory function. In the juvenile- and adult-onset forms, intralysosomal accumulation of glycogen is limited primarily to skeletal muscle, resulting in progressive muscle weakness. Death in all forms is usually related to respiratory failure. Alglucosidase alfa provides an exogenous source of GAA. Binding to mannose-6-phosphate receptors on the cell surface has been shown to occur via carbohydrate groups on the GAA molecule, after which it is internalized and transported into lysosomes, where it undergoes proteolytic cleavage that results in increased enzymatic activity. It then exerts enzymatic activity in cleaving glycogen.

mechanism of action

Alglucosidase alfa is designed to act as an exogenous source of GAA, acting to correct GAA deficiency that is the hallmark of Pompe disease. Alglucosidase alfa binds to mannose-6-phosphate receptors on the cell surface via carbohydrate groups on the GAA molecule, after which it is internalized and transported into lysosomes, where it undergoes proteolytic cleavage that results in increased enzymatic activity. It then exerts enzymatic activity in cleaving glycogen. Specifically, it hydrolyses alpha-1,4-glucose bonds.

toxicity

There have been no reports of overdose with alglucosidase alfa.

half life

2.3 ± 0.4 hours.