study to compare the efficacy and safety of enzyme replacement therapies avalglucosidase alfa and alglucosidase alfa administered every other week in patients with late-onset pompe disease who have not been previously treated for pompe disease

Conditions: Glycogen Storage Disease Type II;Pompe's Disease

Summary: primary objective: to determine the effect of avalglucosidase alfa treatment on respiratory muscle strength measured by percent (%) predicted forced vital capacity (fvc) in the upright position, as compared to alglucosidase alfa. secondary objective: to determine the safety and effect of avalglucosidase alfa treatment on functional endurance (6-minute walk test, inspiratory muscle strength (maximum inspiratory pressure), expiratory muscle strength (maximum expiratory pressure), lower extremity muscle strength (hand-held dynamometry), motor function (quick motor function test), and health-related quality of life (short form-12).

the duration of the study per participant will be up to approximately 6 years that will consist of a 14-day screening period (may be extended up to 8 weeks in pre-specified situations), a 49-week blinded treatment period (except for the subgroup of pediatric patients aged 3 to less than (\<) 18 years enrolling directly in the open-label long-term follow-up phase), a 240-week open-label treatment period, and a 4-week post-treatment observation period.

Eligibility criteria:
inclusion criteria : * the participant has confirmed acid alpha-glucosidase (gaa) enzyme deficiency from any tissue source and/or 2 confirmed gaa gene mutations. * the participant must provide signed, informed consent prior to performing any study related procedures. consent of a legally authorized guardian(s) is (are) required for legally minor participant as defined by local regulation. if the participant is legally minor, signed written consent shall be obtained from parent(s)/legal guardian and assent obtained from participants, if applicable. exclusion criteria: * the participant is \<3 years of age. * the participant has known pompe specific cardiac hypertrophy. * the participant is wheelchair dependent. * the participant is not able to ambulate 40 meters (approximately 130 feet) without stopping and without an assistive device. * the participant requires invasive-ventilation (non-invasive ventilation is allowed). * the participant is not able to successfully perform repeated forced vital capacity (fvc) measurements in upright position of greater than or equal to 30% predicted and less than or equal to 85% predicted. * the participant (and participant's legal guardian if participant is legally minor as defined by local regulation) is (are) not able to comply with the clinical protocol. * the participant has had previous treatment with alglucosidase alfa or any investigational therapy for pompe disease. * the participant has prior or current use of immune tolerance induction therapy. * the participant, if female and of childbearing potential, has a positive pregnancy test (beta-human chorionic gonadotropin) at baseline. the above information is not intended to contain all considerations relevant to a participant's potential participation in a clinical trial.