This is a single group, treatment, Phase 3, open-label study to assess efficacy, safety, pharmacokinetic (PK), pharmacodynamics (PD) of avalglucosidase alfa in treatment-naïve male and female participants with IOPD.

Study details include:

• Study duration: Screening - up to 4 weeks;
• Primary Analysis Period (PAP) - 52 weeks;
• Extended Treatment Period (ETP) - 52 weeks;
• Extended Long term Treatment Period (ELTP) - 104 weeks; 4-week follow-up period for a total study duration - up to 4.08 years.
• Treatment duration: Up to 4 years
• Visit frequency: every other week and potentially every week

Study duration may be variable by country, including at least completion of the PAP and ETP, and up to 4.08 years.

Inclusion Criteria:

• Participants must have confirmed diagnosis of infantile-onset Pompe disease defined as: the presence of 2 lysosomal acid α-glucosidase (GAA) pathogenic variants and a documented GAA deficiency from blood, skin, or muscle tissue; or the presence of 1 GAA pathogenic variant and a documented GAA deficiency from blood, skin and muscle tissue in 2 separate samples (from either 2 different tissues or from the same tissue but at 2 different sampling dates).

• Participants must have established cross-reactive immunological material (CRIM) status available prior to enrollment.

• Participants must have cardiomyopathy at the time of diagnosis: ie, left ventricular mass index (LVMI) equivalent to mean age specific LVMI

  • +1 standard deviation for participants diagnosed by newborn screening or sibling screening;
  • +2 standard deviation for participants diagnosed by clinical evaluation.

• Parents or legally authorized representative(s) must be capable of giving signed informed consent.

Exclusion Criteria:

• Participants with symptoms of respiratory insufficiency, including any ventilation use (invasive or noninvasive) at the time of enrollment.
• Participants with major congenital abnormality.
• Participants with clinically significant organic disease (with the exception of symptoms relating to Pompe disease).
• Participant received any Pompe disease specific treatment, eg enzyme-replacement gene therapy (ERT).
• Participant who has previously been treated in any clinical trial of avalglucosidase alfa.
• Participant not suitable for participation, whatever the reason, as judged by the Investigator, including medical or clinical conditions, or participants potentially at risk of noncompliance to study procedures.

The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.

Qualified researchers may request access to patient level data and related study documents including the clinical study report, study protocol with any amendments, blank case report form, statistical analysis plan, and dataset specifications. Patient level data will be anonymized and study documents will be redacted to protect the privacy of trial participants. Further details on Sanofi's data sharing criteria, eligible studies, and process for requesting access can be found at: https://vivli.org