A Study of rhGAA in Patients With Late-Onset Pompe Disease

Inclusion Criteria: * patient's legally authorized guardian(s) must provide signed, informed consent prior to performing any study-related procedures; patient's signature required if patient understands informed consent * patient must have a diagnosis of Pompe disease based on deficient endogenous GAA activity or GAA gene mutations * patient must have demonstrable muscle weakness * patient must be greater than or equal to five years of age and younger than eighteen years of age * patient must be able to provide 3 reproducible FVC tests in sitting position during screening * patient must perform muscle function testing * patient must ambulate 10 meters (assistive devices permitted) * patient and legal guardian must comply with the clinical protocol Exclusion Criteria: * patient requires the use of invasive ventilatory support * patient requires the use of noninvasive ventilatory support while awake and in an upright position * patient has received enzyme replacement therapy with GAA from any source * patient has used an investigational product within 30 days prior to study enrollment, or is currently enrolled in another clinical or observational study * patient has a medical condition, serious intercurrent illness, or other extenuating circumstance that, may significantly interfere with study compliance, including all prescribed evaluations and follow-up activities * Female patients pregnant, lactating or unwilling to practice birth control methods during study * Male patients unwilling to use barrier contraceptives during study