Skip to content

Evaluation of Efficacy and Safety of a Single Dose of CTX001 in Participants With Transfusion-Dependent β-Thalassemia and Severe Sickle Cell Disease

A Phase 3b Study to Evaluate Efficacy and Safety of a Single Dose of Autologous CRISPR Cas9 Modified CD34+ Human Hematopoietic Stem and Progenitor Cells (CTX001) in Subjects With Transfusion-Dependent β-Thalassemia or Severe Sickle Cell Disease

Status
Recruiting
Phases
Phase 3
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT05477563
Enrollment
26
Registered
2022-07-28
Start date
2022-08-02
Completion date
2027-06-09
Last updated
2026-03-23

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Beta-Thalassemia, Genetic Diseases, Inborn, Hematologic Diseases, Hemoglobinopathies, Sickle Cell Anemia, Sickle Cell Disease, Thalassemia

Brief summary

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.

Interventions

BIOLOGICALCTX001

Administered by intravenous (IV) infusion following myeloablative conditioning with busulfan

Sponsors

Vertex Pharmaceuticals Incorporated
Lead SponsorINDUSTRY

Study design

Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE

Eligibility

Sex/Gender
ALL
Age
12 Years to 35 Years
Healthy volunteers
No

Inclusion criteria

Key Inclusion Criteria: * Participants with TDT and SCD: * 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 Key

Exclusion criteria

* 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 Other protocol defined Inclusion/

Design outcomes

Primary

MeasureTime frame
Fetal Hemoglobin (HbF) Concentration Over TimeUp to 12 Months After CTX001 Infusion
Total Hemoglobin (Hb) Concentration Over TimeUp to 12 Months After CTX001 Infusion

Secondary

MeasureTime frame
TDT and SCD: Number of Participants With Adverse Events (AEs) and Serious Adverse Events (SAEs)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)Within 42 Days After CTX001 Infusion
TDT and SCD: Time to EngraftmentUp to 12 Months After CTX001 Infusion
TDT and SCD: Incidence of Transplant-Related Mortality (TRM) Within 100 Days After CTX001 InfusionWithin 100 Days After CTX001 Infusion
TDT and SCD: Incidence of TRM Within 12 Months After CTX001 InfusionWithin 12 Months After CTX001 Infusion
TDT and SCD: Incidence of All-cause MortalityFrom Signing of Informed Consent up to 12 Months After CTX001 Infusion
TDT and SCD: Relative Reduction in Annualized Volume of RBC TransfusionsFrom Day 60 up to 12 Months After CTX001 Infusion
TDT and SCD: Proportion of Alleles With Intended Genetic Modification Present in Peripheral Blood Over TimeUp 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 TimeUp to 12 Months After CTX001 Infusion
TDT: Duration Transfusion Free in ParticipantsUp to 12 Months After CTX001 Infusion
SCD: Relative Reduction in Annualized Rate of Severe Vaso-Occlusive Crises (VOCs)From Baseline up to 12 Months After CTX001 Infusion
SCD: Relative Reduction in Annualized Rate of Inpatient Hospitalizations for Severe VOCsFrom Baseline up to 12 Months After CTX001 Infusion
SCD: Relative Reduction in Annualized Duration of Hospitalization for Severe VOCsFrom Baseline up to 12 Months After CTX001 Infusion
SCD: Relative Reduction in HaptoglobinFrom Baseline up to 12 Months After CTX001 Infusion
SCD: Relative Reduction in Lactate dehydrogenaseFrom Baseline up to 12 Months After CTX001 Infusion
SCD: Relative Reduction in Total BilirubinFrom Baseline up to 12 Months After CTX001 Infusion
SCD: Relative Reduction in Indirect BilirubinFrom Baseline up to 12 Months After CTX001 Infusion

Countries

Germany, Italy, Saudi Arabia, United States

Contacts

CONTACTMedical Information
medicalinfo@vrtx.com6173416777

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Mar 24, 2026