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NCT Number: NCT05329649

Evaluation of Safety and Efficacy of CTX001 in Pediatric Participants With Severe Sickle Cell Disease (SCD)

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

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This study is active but is not currently recruiting participants.

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Key information

Conditions

Sickle Cell Disease Anemia Anemia, Hemolytic Anemia, Hemolytic, Congenital Anemia, Sickle Cell Congenital, Hereditary, and Neonatal Diseases and Abnormalities Genetic Diseases, Inborn Hematologic Diseases Hematological Diseases Hemic and Lymphatic Diseases Hemoglobinopathies Hydroxyurea Failure Hydroxyurea Intolerance

Age range

2 year–11 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 3

Primary location

University Hospital Duesseldorf - Department of Pediatric Oncology, Hematology and Clinical Immunology, Düsseldorf, Germany

Loading trial locations.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Key Inclusion Criteria:

  • 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
  • Hydroxyurea (HU) failure unless HU intolerant
  • Eligible for autologous stem cell transplant as per investigators judgment

Key Exclusion Criteria:

  • A willing and healthy 10/10 human leukocyte antigen (HLA)-matched related donor
  • Prior hematopoietic stem cell transplant (HSCT).
  • Clinically significant and active bacterial, viral, fungal, or parasitic infection

Other protocol defined Inclusion/Exclusion criteria may apply.

Treatment and study plan

CTX001

Biological

Administered by intravenous infusion following myeloablative conditioning with busulfan.

Other names: Exagamglogene autotemcel, Exa-cel

Primary outcomes

  1. Proportion of Participants who do not Have any Severe Vaso-occlusive Crises (VOCs) for at Least 12 Consecutive Months (VF12)

    Time frame: Up to 24 Months After CTX001 Infusion

Secondary outcomes

  1. Proportion of Participants Free from Inpatient Hospitalization for Severe VOCs for at Least 12 Months (HF12)

    Time frame: Up to 24 Months After CTX001 Infusion

  2. Relative Reduction in Annualized Rate of Severe VOCs

    Time frame: From Baseline up to 24 Months After CTX001 Infusion

  3. Duration of Severe VOC Free in Participants who Have Achieved VF12

    Time frame: Up to 24 Months After CTX001 Infusion

  4. Relative Reduction in Annualized Rate of Inpatient Hospitalizations for Severe VOCs

    Time frame: From Baseline up to 24 Months After CTX001 Infusion

  5. Proportion of Participants With Sustained Fetal Hemoglobin (HbF) ≥20 Percent (%) for at Least 3 Months

    Time frame: Up to 24 Months After CTX001 Infusion

  6. Proportion of Participants With Sustained HbF ≥20% for at Least 6 Months

    Time frame: Up to 24 Months After CTX001 Infusion

  7. Proportion of Participants With Sustained HbF ≥20% for at Least 12 Months

    Time frame: Up to 24 Months After CTX001 Infusion

  8. Proportion of Alleles With Intended Genetic Modification Present in Peripheral Blood Over Time

    Time frame: Up to 24 Months After CTX001 Infusion

  9. Proportion of Alleles With Intended Genetic Modification Present in CD34+ Cells of the Bone Marrow Over Time

    Time frame: Up to 24 Months After CTX001 Infusion

  10. Number of Participants With Adverse Events (AEs) and Serious Adverse Events (SAEs)

    Time frame: From Signing of Informed Consent up to 24 Months After CTX001 Infusion

  11. 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

  12. Time to Engraftment

    Time frame: Up to 24 Months After CTX001 Infusion

  13. Incidence of Transplant-related Mortality (TRM) Within 100 Days After CTX001 Infusion

    Time frame: Within 100 Days After CTX001 infusion

  14. Incidence of TRM Within 12 Months After CTX001 Infusion

    Time frame: Within 12 Months After Infusion

  15. Incidence of All-cause Mortality

    Time frame: From Signing of Informed Consent up to 24 Months After CTX001 Infusion

  16. Relative Reduction in Annualized Duration of Hospitalization for Severe VOCs

    Time frame: From Baseline up to 24 Months After CTX001 Infusion

  17. Proportion of Participants With Sustained HbF ≥30% for at Least 3 Months

    Time frame: Up to 24 Months After CTX001 Infusion

  18. Proportion of Participants With Sustained HbF ≥30% for at Least 6 Months

    Time frame: Up to 24 Months After CTX001 Infusion

  19. Proportion of Participants With Sustained HbF ≥30% for at Least 12 Months

    Time frame: Up to 24 Months After CTX001 Infusion

  20. Time for Participants to Reach HbF ≥20%

    Time frame: Up to 24 Months After CTX001 Infusion

  21. Time for Participants to Reach HbF ≥30%

    Time frame: Up to 24 Months After CTX001 Infusion

  22. Relative Reduction from Baseline in Annualized Volume and Episodes of RBC Transfusions for SCD-related indications starting after Month 12 post-CTX001 infusion

    Time frame: Up to 24 Months After CTX001 Infusion

  23. HbF Concentrations Over Time

    Time frame: Up to 24 Months After CTX001 Infusion

  24. Hemoglobin (Hb) Concentrations Over Time

    Time frame: Up to 24 Months After CTX001 Infusion

  25. Change in Reticulocyte Count Over Time

    Time frame: From Baseline up to 24 Months After CTX001 Infusion

  26. Change in Indirect Bilirubin Over Time

    Time frame: From Baseline up to 24 Months After CTX001 Infusion

  27. Change in Haptoglobin Over Time

    Time frame: From Baseline up to 24 Months After CTX001 Infusion

  28. Proportion of Participants with Detectable Haptoglobin Over Time

    Time frame: Up to 24 Months After CTX001 Infusion

  29. Change in Lactate Dehydrogenase (LDH) Over Time

    Time frame: From Baseline (Pre-infusion) up to 24 Months After CTX001 Infusion

  30. Proportion of Participants with Normalized LDH Over Time

    Time frame: Up to 24 Months After CTX001 Infusion

Sponsors and collaborators

Lead sponsor

Vertex Pharmaceuticals Incorporated

Industry

Collaborators

  • CRISPR Therapeutics

Registry information

Official study title

A Phase 3 Study to Evaluate the Safety and Efficacy of a Single Dose of CTX001 in Pediatric Subjects With Severe Sickle Cell Disease

Important dates

Study start
2022
Primary completion
2027
Study completion
2027
First posted
Apr 15, 2022
Registry last updated
Jul 1, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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