Pompe disease is an autosomal recessive muscle-wasting disorder caused by the 
deficiency of the lysosomal enzyme acid alpha-glucosidase. Due to virtual 
absence of acid alpha-glucosidase, patients with classical infantile Pompe 
disease develop progressive cardiomyopathy, skeletal muscle weakness and 
respiratory insufficiency leading to death in early infancy. We report on the 
results of a phase II clinical trial including two patients with classical 
infantile Pompe disease receiving enzyme replacement therapy over a period of 48 
weeks by weekly infusions. Recombinant acid alpha-glucosidase was derived from 
the milk of transgenic rabbits. Safety was evaluated by recording adverse events 
while clinical efficacy was evaluated by ventilator-free survival, left 
ventricular mass index, motor development as well as histologic and biochemical 
analysis of muscle biopsies. This therapy was in general well-tolerated. There 
was an overall improvement in left ventricular mass, cardiac function, skeletal 
muscle function and histological appearance of skeletal muscle.