This is a single group, 52-week treatment, Phase 4, open-label, single-arm study to assess the safety and efficacy of avalglucosidase alfa IV infusion in male and female Chinese participants with IOPD who are treatment-naïve or were previously treated with ERT.

Study details include:

• The study duration: total study duration is approximately 64 weeks.

  • Screening period of up to 8 weeks
  • Treatment period of 52 weeks
  • Follow-up period of 4 weeks. (if the participant enrolls in another study or receives commercially available ERT, the follow-up period may be reduced from 4 to 2 weeks)

• The number of visits will be 30, including 29 site visits and 1 phone call follow-up visit.

Inclusion Criteria:

• Participant must be <18 years of age, at the time of signing the informed consent.
• Participants have documented onset of Pompe disease symptoms before 12 months of age (corrected for gestation if born before 40 weeks); and diagnosis of IOPD is confirmed by GAA enzyme deficiency from any tissue source and GAA gene pathogenic mutations.
• Participants must have documented cardiomyopathy at the time of diagnosis.
• Contraceptive use should be consistent with local regulations Participant's parent/legally authorized representative (LAR) must be capable of giving signed informed consent.

Exclusion Criteria: Participants are excluded from the study if any of the following criteria apply:

• Participants with major congenital abnormality that, in the opinion of the Investigator, would preclude participation in the study or potentially decrease survival.
• Participants with clinically significant organic disease (with the exception of symptoms relating to Pompe disease).
• Participants who have received an ERT other than alglucosidase alfa or avalglucosidase alfa, or any other treatment for Pompe disease, including gene therapy prior to the enrollment.
• Participants who have received alglucosidase alfa or avalglucosidase alfa less than 1 week prior to the first dose of avalglucosidase alfa given as IMP Participants who are anticipated to take prohibited therapy (ie, any other treatment for Pompe disease) during this study.
• Participants who have taken other investigational drugs (not Pompe disease specific) within 30 days or 5 elimination half-lives in blood of that drug before enrollment, whichever is longer, or are anticipated to take any other concurrent investigational treatments.
• Participants 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