Avalglucosidase alfa is in clinical development for the treatment of late-onset Pompe disease. Pompe disease is an inherited, genetic disorder which results in the deficiency of the enzyme ‘acid alpha-glucosidase’ (GAA). This deficiency leads to progressive accumulation of glycogen, a type of sugar, usually stored in muscle tissues particularly around the heart, skeletal muscle and respiratory muscles. Late-onset Pompe disease develop after one year of age, and is a serious, progressive, debilitating, and ultimately life threatening disease associated with high morbidity. Enzyme replacement therapy with alglucosidase alfa is a recommended treatment approach but the main drawback of the current option is the limited uptake by affected muscles leading to limited clinical benefits in some patients.