VAL-1221 Delivered Intravenously in Ambulatory and Ventilator-free Participants With Late-Onset Pompe Disease

Part 1 comprises 3 sequential cohorts of 4 patients each randomized to treatment with either VAL-1221 (at 3, 10, or 30 mg/kg) or positive control (rhGAA). Patients randomized to VAL-1221 will receive 7 intravenous (IV) infusions of VAL-1221 (one infusion every other week) over 12 weeks. Control patients will continue receiving their accustomed dose and regimen of Myozyme®. Part 2 is an uncontrolled extension to evaluate long-term effects of VAL-1221 given by IV infusion once every other week at doses up to 40 mg/kg.