Long - Term Follow Up of Sickle Cell Disease and Beta-thalassemia Subjects Previously Exposed to BIVV003 or ST-400.

An Observational Long-term Safety and Efficacy Follow-up Study After Ex-vivo Gene Therapy With BIVV003 in Participants With Severe Sickle Cell Disease (SCD) or With ST-400 in Participants With Transfusion-dependent Beta-thalassemia (TDT) With Autologous Hematopoietic Stem Cell Transplant

Primary Objectives:

Long-term safety of BIVV003 in participants with severe sickle cell disease (SCD) and ST- 400 in participants with transfusion-dependent beta-thalassemia (TDT)

Secondary Objectives:

• Long-term efficacy of the biological treatment effect of BIVV003 in SCD
• Long-term efficacy of the clinical treatment effect of BIVV003 on SCD-related clinical events
• Long-term efficacy of the biological treatment effect of ST-400 in TDT
• Long-term efficacy of the clinical treatment effect of ST-400 in TDT

The total study duration is up to 15 years of follow-up post BIVV003 and/or ST-400 infusion.

Inclusion Criteria:

• Received treatment with BIVV003 or ST-400 in one of the parent studies (ACT16222, ST- 400-01) or any future studies with BIVV003
• Capable of giving signed informed consent (and if applicable assent)

Exclusion Criteria:

• Unable to comply with study visit schedule or study procedures
• Any other reason that, in the opinion of the Investigator or Medical Monitor, would render the participant unsuitable for participation in the study The above information is not intended to contain all considerations relevant to a potential participation in a clinical trial.