EDIT-301 for Autologous Hematopoietic Stem Cell Transplant (HSCT) in Participants With Transfusion-Dependent Beta Thalassemia (TDT)

Inclusion Criteria

• Key Inclusion Criteria: Diagnosis of Transfusion Dependent B-Thalassemia as defined by: - Documented homozygous β-thalassemia or compound heterozygous β-thalassemia including β-thalassemia/hemoglobin E (HbE) based on historical data in medical records, and - History of at least 100 mL/kg/year or 10 U/year of packed red blood cell (RBC) transfusions in the 2 years prior to signing informed consent - Clinically stable and eligible to undergo autologous HSCT - Karnofsky Performance Status ≥ 70 Key Exclusion Criteria: - Available 10/10 human leukocyte antigen (HLA)-matched related donor - Prior HSCT or contraindications to autologous HSCT - Participants with associated a history of α-thalassemia and > 1 alpha chain deletion, or alpha multiplications as documented in medical records - Participants with a history of other inherited hemoglobinopathy or thalassemic mutation (Hb S, C, D or other) as documented in medical records - Prior receipt of gene therapy - Inadequate bone marrow function, as defined by white blood cell count of < 3 x 10^9/L or a platelet count < 100 x 10^9/L (without hypersplenism), per investigator judgement - Inadequate organ function - Advanced liver disease - Any prior or current malignancy, or immunodeficiency disorder, - Immediate family member with a known or suspected Familial Cancer Syndrome - Clinically significant and active bacterial, viral, fungal, or parasitic infection