Evaluation of Safety and Efficacy of CTX001 in Pediatric Participants With Transfusion-Dependent β-Thalassemia (TDT)

Vertex Pharmaceuticals

Status and phase: Enrolling; Phase 3

Conditions: Thalassemia; Beta-Thalassemia; Hemoglobinopathies; Genetic Diseases, Inborn; Hematologic Diseases

Treatments: Biological: CTX001

Study type: Interventional

Funder types: Industry

Identifiers

NCT05356195

2021-002172-39 (EudraCT Number)

VX21-CTX001-141

Details and patient eligibility

About

This is a single-dose, open-label study in pediatric participants with TDT. The study will evaluate the safety and efficacy of autologous CRISPR-Cas9 modified CD34+ human hematopoietic stem and progenitor cells (hHSPCs) (CTX001).

Enrollment: 15 estimated patients

Sex: All

Ages: 2 to 11 years old

Volunteers: No Healthy Volunteers

Inclusion and 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.

Trial design

Primary purpose: Treatment

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

---

15 participants in 1 patient group

CTX001

Experimental group

Description:

CTX001 (autologous CD34+ hHSPCs modified with CRISPR-Cas9 at the erythroid lineage-specific enhancer of the BCL11A gene). Participants will receive single infusion of CTX001 through central venous catheter.

Treatment:

Biological: CTX001