Improving the treatment of Pompe disease with enzyme replacement therapy: current strategies and clinical evidence

Introduction: Pompe disease (PD) is a rare genetic disorder that leads to intralysosomal glycogen accumulation because of a deficiency in the lysosomal enzyme acid α-glucosidase (GAA), which is required to break down glycogen to glucose. Enzyme replacement therapy (ERT) with recombinant human GAA (rhGAA) supplies exogenous GAA to reduce glycogen deposits, thereby improving motor and respiratory functioning. Area covered: The first approved ERT for PD was the rhGAA alglucosidase alfa. Limitations associated with this treatment led to the development of two other rhGAAs: avalglucosidase alfa and cipaglucosidase alfa. This review describes the limitations of alglucosidase alfa and focuses on the strategies used to overcome these limitations, including the conjugation of multiple synthetic bis-M6P - containing hexasaccharides to sialic acids present on the enzyme, thus enhancing M6PR targeting, enzyme uptake, glycogen clearance, and therapeutic outcomes. Efficacy and safety of avalglucosidase alfa in late-onset and infantile-onset PD are also discussed. A brief overview of the newest ERT, cipaglucosidase alfa, is also provided. Expert opinion: While ERT for PD continues to improve with more effective enzymes like avalglucosidase alfa, the future lies in integrated approaches that combine different therapeutic modalities (gene therapy, substrate reduction therapy) and the use of biomarkers to individualize treatment.