Eligible for autologous stem cell transplant as per investigator's judgment.
Participants with TDT:
Diagnosis of TDT as defined by:
Documented homozygous β-thalassemia or compound heterozygous β-thalassemia including β-thalassemia/hemoglobin E (HbE). Participants can be enrolled based on historical data, but a confirmation of the genotype using the study central laboratory will be required before busulfan conditioning
History of at least 100 milliliter (mL)/kilograms (kg)/year or 10 units/year of packed red blood cells (RBC) transfusions in the prior 2 years before signing the consent or the last rescreening for patients going through re-screening
Participants with SCD:
Diagnosis of severe SCD as defined by:
Documented SCD genotypes
History of at least two severe VOCs events per year for the previous two years prior to enrollment
You may not be if
Participants with TDT and SCD:
A willing and healthy 10/10 human leukocyte antigen (HLA)-matched related donor is available per investigator's judgement
Prior hematopoietic stem cell transplant (HSCT)
Clinically significant and active bacterial, viral, fungal, or parasitic infection as determined by the investigator
Participants with TDT:
Participants with associated α-thalassemia and \>1 alpha deletion, or alpha multiplications
Participants with sickle cell β-thalassemia variant
Participants with SCD:
History of untreated moyamoya syndrome or presence of moyamoya syndrome at screening
Clareo Health | Evaluation of Efficacy and Safety of a Single Dose of CTX001 in Participants With Transfusion-Dependent β-Thalassemia and Severe Sickle Cell Disease
