Treatment of Anderson–Fabry disease

Anderson–Fabry disease (AFD) (OMIM 301500), is an X-linked, metabolic disorder characterised by a defect in the degradation of glycosphingolipids with terminal α-galactose residues that leads to progressive intralysosomal accumulation of globotriaosylceramide (Gb₃) in various tissues of the human body (mainly skin, nervous system, eye, kidney and heart). The underlying cause is a mutation in the gene encoding the lysosomal enzyme α-galactosidase A. The multisystemic involvement in classically affected men leads to premature death during the fourth or fifth decade due to renal failure, cerebrovascular and cardiac complications. Heterozygous female patients may have a wide range of disease severity, ranging from a relatively benign course to manifestations comparable with those of hemizygous men.1

Cardiovascular involvement is complex as Gb₃ storage occurs in a wide spectrum of myocardial tissues, including endothelial cells and vessel walls, cardiomyocytes, conduction system cells and valvular fibroblasts. Main clinical manifestations include left ventricular hypertrophy associated with diastolic dysfunction and symptoms of heart failure; decreased coronary flow reserve caused either by functional impairment or fixed stenotic lesions of large epicardial coronary arteries; and arrhythmias.2

Recent advances in molecular genetic techniques have led to the development of enzyme replacement therapy (ERT) by recombinant α-galactosidase A. Based on human studies showing promising histological and clinical changes, two enzyme preparations have been approved for the treatment of AFD in Europe: agalsidase alfa (Replagal, Shire Human Genetics, Cambridge, MA, USA) and agalsidase beta (Fabrazyme, Cambridge, MA, USA). In the United States only agalsidase beta has been approved. Agalsidase alfa is the product of a continuous line of human fibroblasts, given biweekly in a dose of 0.2 mg/kg. Agalsidase beta is produced by cDNA transduction in Chinese hamster ovary cells, administered biweekly in a dose of 1.0 mg/kg. Although both proteins have identical amino acid sequences, they differ in …