A Phase 3 interventional study of CTX001 in Beta-Thalassemia, Thalassemia and Hematologic Diseases, sponsored by Vertex Pharmaceuticals Incorporated. Recruiting at 6 sites in 4 countries. Open to participants aged 12 Years to 35 Years. Per ClinicalTrials.gov, last updated 2026-03-23.
Sponsored by Vertex Pharmaceuticals Incorporated · Phase 3, Interventional, and Treatment
This is a single-dose, open-label study in participants with transfusion-dependent β-thalassemia (TDT) or severe sickle cell disease (SCD). The study will evaluate the safety and efficacy of autologous CRISPR-Cas9 modified CD34+ human hematopoietic stem and progenitor cells (hHSPCs) using CTX001.
294 studies on the registry are indexed under beta-Thalassemia; 69 are open to participants now.
This study's planned enrollment of 26 is below the median of 40 across 208 interventional studies indexed under beta-Thalassemia.
Browse beta-Thalassemia studies →Vertex Pharmaceuticals Incorporated is the lead sponsor of 249 studies on the registry; 17 are open to participants now.
Of its 106 completed or terminated interventional studies of FDA-regulated products, 53 (50%) have results posted.
Counted across the registry records on this site, refreshed daily.
Key Inclusion Criteria:
Key Exclusion Criteria:
Other protocol defined Inclusion/Exclusion criteria may apply.
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Stem cell (bone marrow) transplants. Allogeneic uses cells from a donor; autologous uses your own cells, collected earlier and given back.
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Allogeneic and autologous transplant
Stem cell (bone marrow) transplants. Allogeneic uses cells from a donor; autologous uses your own cells, collected earlier and given back.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hemoglobin (Hb)
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
CTX001 (autologous CD34+ hHSPCs modified with CRISPR-Cas9 at the erythroid lineage-specific enhancer of the BCL11A gene). Participants will receive a single infusion of CTX001 through a central venous catheter.
Biological: CTX001
Administered by intravenous (IV) infusion following myeloablative conditioning with busulfan
Also known as: Exagamglogene autotemcel, Exa-cel
Fetal Hemoglobin (HbF) Concentration Over Time
Time frame: Up to 12 Months After CTX001 Infusion
Total Hemoglobin (Hb) Concentration Over Time
Time frame: Up to 12 Months After CTX001 Infusion
TDT and SCD: Number of Participants With Adverse Events (AEs) and Serious Adverse Events (SAEs)
Time frame: From Signing of Informed Consent up to 12 Months After CTX001 Infusion
TDT and SCD: Proportion of Participants With Engraftment (First day of 3 Consecutive Measurements of Absolute Neutrophil Count (ANC) >=500 per Microliter [mcgL] on 3 Different Days)
Time frame: Within 42 Days After CTX001 Infusion
TDT and SCD: Time to Engraftment
Time frame: Up to 12 Months After CTX001 Infusion
TDT and SCD: Incidence of Transplant-Related Mortality (TRM) Within 100 Days After CTX001 Infusion
Time frame: Within 100 Days After CTX001 Infusion
TDT and SCD: Incidence of TRM Within 12 Months After CTX001 Infusion
Time frame: Within 12 Months After CTX001 Infusion
TDT and SCD: Incidence of All-cause Mortality
Time frame: From Signing of Informed Consent up to 12 Months After CTX001 Infusion
TDT and SCD: Relative Reduction in Annualized Volume of RBC Transfusions
Time frame: From Day 60 up to 12 Months After CTX001 Infusion
TDT and SCD: Proportion of Alleles With Intended Genetic Modification Present in Peripheral Blood Over Time
Time frame: Up to 12 Months After CTX001 Infusion
TDT and SCD: Proportion of Alleles With Intended Genetic Modification Present in CD34+ Cells of the Bone Marrow Over Time
Time frame: Up to 12 Months After CTX001 Infusion
TDT: Duration Transfusion Free in Participants
Time frame: Up to 12 Months After CTX001 Infusion
SCD: Relative Reduction in Annualized Rate of Severe Vaso-Occlusive Crises (VOCs)
Time frame: From Baseline up to 12 Months After CTX001 Infusion
SCD: Relative Reduction in Annualized Rate of Inpatient Hospitalizations for Severe VOCs
Time frame: From Baseline up to 12 Months After CTX001 Infusion
SCD: Relative Reduction in Annualized Duration of Hospitalization for Severe VOCs
Time frame: From Baseline up to 12 Months After CTX001 Infusion
SCD: Relative Reduction in Haptoglobin
Time frame: From Baseline up to 12 Months After CTX001 Infusion
SCD: Relative Reduction in Lactate dehydrogenase
Time frame: From Baseline up to 12 Months After CTX001 Infusion
SCD: Relative Reduction in Total Bilirubin
Time frame: From Baseline up to 12 Months After CTX001 Infusion
SCD: Relative Reduction in Indirect Bilirubin
Time frame: From Baseline up to 12 Months After CTX001 Infusion
Plan to share: No — Details on Vertex data sharing criteria and process for requesting access can be found at: https://www.vrtx.com/our-science/clinical-trials-data-sharing/
No publications or documents are linked to this record.
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Studies of the drug tested here: Exagamglogene autotemcel
Vertex Pharmaceuticals Incorporated →