A Study to Assess Safety and Efficacy of Avalglucosidase Alfa Administered Every Other Week in Pediatric Patients With Infantile-onset Pompe Disease Previously Treated With Alglucosidase Alfa

The duration of the study for each participant will be up to 9 years and 4 months that will consist of a 14-day screening period, that may be extended to up to 4 weeks in pre-specified situations. This is followed by a 25-week treatment period and an up to a 462-week treatment extension period and a 4-week post-treatment observation period. Cohort 1 and 2 (Cohort 1: avalglucosidase alfa 20 milligrams per kilogram \[mg/kg\], Cohort 2: avalglucosidase alfa 40 mg/kg) will be non-randomized and Cohort 3 (Cohort 3a: avalglucosidase alfa 40 mg/kg \[maximum tolerated dose\] and Cohort 3b: alglucosidase alfa) will be randomized.

Age

0–17

Sex

ALL

Healthy volunteers

Accepted

You may be eligible if

The participants has confirmed acid alpha-glucosidase (GAA) enzyme deficiency from any tissue source.
The participants who has reached legal age of majority as defined by local regulation, or the participant's legal guardian(s) must provide signed informed consent prior to performing any study-related procedures. If the participant is legally minor per local regulations, assent shall be obtained from participants, if applicable.
The participants (and participant's legal guardian if participant is legally minor as defined by local regulation) must have the ability to comply with the clinical protocol.
The participants is less than 18 years old.
The participants, if female and of childbearing potential, must have a negative serum pregnancy test (beta-human chorionic gonadotropin) and must not breastfeeding at screening/Baseline.
The participant has cardiomyopathy at the time of diagnosis: i.e., left ventricular mass index (LVMI) equivalent to mean age specific LVMI plus 2 standard deviations.
The participant has been receiving a stable dose of alglucosidase alfa regularly for a minimum of 6 months immediately prior to study entry.
For participants in Stage 1: The participant has documented evidence of clinical decline in at least 1 of the following parameters related to Pompe Disease and not related to intercurrent illness as assessed by the Investigator: respiratory function, motor skills, and/or cardiac parameters.
For participants in Stage 2: The participant has documented evidence of suboptimal clinical response in at least 1 of the following parameters related to Pompe Disease and not related to intercurrent illness as assessed by the Investigator: respiratory function, motor skills, and/or new onset of ptosis.

You may not be if

Participants are excluded from the study if any of the following criteria apply:
The participant has high antibody titer to alglucosidase alfa.
The participant has a high risk for a severe allergic reaction to neoGAA (avalglucosidase alfa).
The participant requires any prohibited concomitant medications (e.g., immune modulatory treatment) for the duration of the study.
The participant has previously participated in any ACT14132 study cohort.
Female participant of childbearing potential not protected by highly effective contraceptive method of birth control and/or who is unwilling or unable to tested for pregnancy.
The above information is not intended to contain all considerations relevant to a participant's potential participation in a clinical trial.

What this study is about