Evaluating CTX001 for treating pediatric beta-thalassemia

A Phase 3 Study to Evaluate the Safety and Efficacy of a Single Dose of CTX001 in Pediatric Subjects With Transfusion-Dependent β-Thalassemia

Phase 3 Interventional Vertex Pharmaceuticals Incorporated · NCT05356195

This study is testing a new treatment using gene editing to see if it can help kids with beta-thalassemia reduce or stop their need for blood transfusions.

Quick facts

PhasePhase 3
Study typeInterventional
Enrollment15 (estimated)
Ages2 Years to 11 Years
SexAll
SponsorVertex Pharmaceuticals Incorporated Industry-sponsored
Locations6 sites (Nashville, Tennessee and 5 other locations)
Trial IDNCT05356195 on ClinicalTrials.gov

What this trial studies

This clinical trial is an open-label, single-dose intervention aimed at assessing the safety and efficacy of CTX001, which involves modifying a patient's own hematopoietic stem and progenitor cells using CRISPR-Cas9 technology. The study focuses on pediatric participants diagnosed with transfusion-dependent beta-thalassemia (TDT) who have a significant history of blood transfusions. Participants will undergo a conditioning regimen before receiving the modified cells, with the goal of reducing or eliminating their need for transfusions. The trial will monitor both the safety and effectiveness of this innovative treatment approach.

Who should consider this trial

Good fit: Ideal candidates are pediatric patients diagnosed with transfusion-dependent beta-thalassemia who have a history of frequent blood transfusions.

Not a fit: Patients who have a suitable HLA-matched donor for a traditional stem cell transplant may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could significantly reduce or eliminate the need for blood transfusions in children with beta-thalassemia.

How similar studies have performed: Other studies using CRISPR technology for genetic diseases have shown promising results, indicating potential for success in this novel approach.

Eligibility criteria

Show full inclusion / exclusion criteria
Key Inclusion Criteria:

* Diagnosis of TDT as defined by:

  * Documented homozygous 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 mL/kilograms (kg)/year of packed RBC transfusions in the prior 24 months before signing of consent (or the last rescreening for patients going through repeat screening) or, for participants initiating transfusion therapy \<24 months before signing of consent, requirement for packed RBC transfusion at least every 3 to 4 weeks for ≥6 months
* Eligible for autologous stem cell transplant as per investigator's judgment.

Key Exclusion Criteria:

* 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)
* Participants with associated α-thalassemia and \>1 alpha deletion, or alpha multiplications
* Participants with sickle cell β-thalassemia variant
* Clinically significant and active bacterial, viral, fungal, or parasitic infection as determined by the investigator

Other protocol defined Inclusion/Exclusion criteria may apply.

Where this trial is running

Nashville, Tennessee and 5 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Beta-ThalassemiaThalassemiaGenetic Diseases, InbornHematologic DiseasesHemoglobinopathies
Last reviewed 2026-06-09 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.