Early access
Sign in
Taking people in United StatesPhase 3

Tests a one-time gene-edited cell treatment in beta-thalassemia and sickle cell disease

Tests CTX001, gene-edited blood stem cells, in people with beta-thalassemia or sickle cell disease.

Key facts

Who runs it
Vertex Pharmaceuticals Incorporated
Where
Charlotte, Nashville, and New York, United StatesSee the 3 sitesAlso in 3 other countries, 3 sites
Registry title
Evaluation of Efficacy and Safety of a Single Dose of CTX001 in Participants With Transfusion-Dependent β-Thalassemia and Severe Sickle Cell Disease
Status
Recruiting
Phase
Phase 3
People taking part
26 people, planned
Started
2 Aug 2022
Expected to end
9 Jun 2027
Type of study
Interventional
Treatments tested
  • CTX001
Record updated
23 March 2026

Who can take part

AI summary

From the trial's eligibility criteria. Machine-read from the registry text on this page, so it can be wrong. The registry text below and the trial team decide who can take part.

The trial is looking for people aged 12 to 35 with transfusion-dependent β-thalassemia or severe sickle cell disease who can have a stem cell transplant using their own cells.

Age
12 to 35 years
Sex
All sexes can join.
Disease stage
Transfusion-dependent β-thalassemia: at least 100 mL/kg/year or 10 units/year of red blood cell transfusions in the past 2 years. Severe sickle cell disease: at least two severe vaso-occlusive crises per year in the past two years.
Earlier treatment
People who have had a stem cell transplant before cannot join.
Biomarker or test result
Thalassemia: documented homozygous or compound heterozygous β-thalassemia, including β-thalassemia/hemoglobin E, confirmed by the study laboratory before busulfan conditioning. Sickle cell disease: documented sickle cell disease genotype.

Main reasons for not taking part

  • A willing, healthy 10/10 HLA-compatible related donor is available
  • Earlier hematopoietic stem cell transplant
  • Clinically significant active infection (bacterial, viral, fungal or parasitic)
  • Thalassemia: more than 1 alpha deletion, alpha multiplications, or sickle cell β-thalassemia variant
  • Sickle cell disease: untreated or current moyamoya syndrome

The registry criteria, word for word

Show all 19 criteriaShow less

Who can take part

  • 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

Who cannot take part

  • Prior hematopoietic stem cell transplant (HSCT)
  • Clinically significant and active bacterial, viral, fungal, or parasitic infection as determined by the investigator
  • History of untreated moyamoya syndrome or presence of moyamoya syndrome at screening; Other protocol defined Inclusion/Exclusion criteria may apply
  • A willing and healthy 10/10 human leukocyte antigen (HLA)-matched related donor is available per investigator's judgement
  • Participants with TDT and SCD:
  • 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:

Check if you might fit

Answer for yourself. This is not a decision: only the study team can say whether you can take part.

  • Are you between 12 and 35 years old?

Where in United States

Also in 3 other countries, 3 sites

  • Levine Children's Hospital - HematologyCharlotte, United StatesTaking people
  • TriStar Medical Group Children's Specialists - Pediatric OncologyNashville, United StatesTaking people
  • New York Presbyterian Hospital - Morgan Stanley Children's HospitalNew York, United StatesTaking people

About the trial

What the trial wants to find out

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.

The group in the trial

  • CTX001Treatment being tested

    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.

Questions to ask the study team

  1. How often do I need to come in, and for how long each time?
  2. Are travel costs paid?
  3. Can I keep my own doctor?
  4. What happens if I want to stop?

Contact the study team: see the registry record → Contacts and Locations

Print a page for my doctor

Data and sources

Registry record
Listed on ClinicalTrials.gov and on the EU's official list of trials (CTIS).
Official title
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
Plain-language title
Tests a one-time gene-edited cell treatment in beta-thalassemia and sickle cell diseaseGenerated from the registry record. The registry title is the official one.
AI summary
From the trial's eligibility criteria. Read by machine on 12 November 2026.
Fit questions
Built from NCT05477563, who can take part
Record updated
23 March 2026