A Long-term Follow-up Study in Participants Who Received CTX001

Recruitment Status
ENROLLING BY INVITATION
(See Contacts and Locations)Verified July 2025 by Vertex Pharmaceuticals Incorporated
Sponsor
Vertex Pharmaceuticals Incorporated
Information Provided by (Responsible Party)
Vertex Pharmaceuticals Incorporated
Clinicaltrials.gov Identifier
NCT04208529
Other Study ID Numbers:
VX18-CTX001-131
First Submitted
December 19, 2019
First Posted
December 22, 2019
Last Update Posted
March 24, 2026
Last Verified
July 2025

ClinicalTrials.gov processed this data on March 2026. Link to the current ClinicalTrials.gov record .

History of Changes

Study Details

Study Description

Condition or DiseaseIntervention/Treatment
Beta-ThalassemiaThalassemiaSickle Cell DiseaseHematologic DiseasesHemoglobinopathiesGenetic Diseases, InbornSickle Cell Anemia
Biological: CTX001

Study Design

Study TypeInterventional
Actual Enrollment160 participants
Design AllocationN/A
Interventional ModelSingle Group Assignment
MaskingNone (Open Label)
Primary PurposeOther
Official TitleA Long-term Follow-up Study of Subjects With β-thalassemia or Sickle Cell Disease Treated With Autologous CRISPR-Cas9 Modified Hematopoietic Stem Cells (CTX001)
Study Start DateJanuary 19, 2021
Actual Primary Completion Date13yrs 4mos from now
Actual Study Completion Date13yrs 4mos from now

Groups and Cohorts

Group/CohortIntervention/Treatment
CTX001
All participants who complete or discontinue one of the multiple parent studies (CTX001-111, CTX001-121, CTX001-141, CTX001-151 and CTX001-161) after CTX001 infusion will be asked to participate in this long-term follow-up study.
Biological: CTX001
CTX001 infusion.

Outcome Measures

Primary Outcome Measures
  1. New malignancies
  2. New or worsening hematologic disorders
  3. All-cause mortality
  4. Serious adverse events (SAEs)
  5. CTX001-related adverse events (AEs)
Secondary Outcome Measures
  1. TDT and SCD: Total Hemoglobin (Hb) concentration over time
  2. TDT and SCD: Fetal Hemoglobin (HbF) concentration over time
  3. TDT and SCD: Proportion of alleles with intended genetic modification present in peripheral blood over time
  4. TDT and SCD: Proportion of alleles with intended genetic modification present in CD34+ cells of the bone marrow over time
  5. TDT and SCD: Change in patient-reported outcome (PRO) over time in participants ≥18 years of age assessed using EuroQol quality of life scale (EQ-5D-5L) for participants from study 111 and 121 only
  6. TDT and SCD: Change in PROs over time in participants ≥18 years of age assessed using functional assessment of cancer therapy-bone marrow transplant (FACT-BMT) questionnaire for participants from study 111, 121 and 161 only
  7. TDT and SCD: Change in PROs over time in participants <18 years assessed using EQ-5D-Youth (EQ-5D-Y) from study 111,121,141 and 151 only
  8. TDT and SCD: Change in PROs over time in participants <18 years assessed using pediatric quality of life inventory (PedsQL) Core
  9. TDT: Proportion of participants achieving transfusion independence for at least 12 consecutive months (TI12)
  10. TDT: Proportion of participants achieving transfusion independence for at least 6 consecutive months (TI6)
  11. TDT: Proportion of participants achieving at least 95%, 90%, 85%, 75%, 50% reduction from baseline in annualized volume of RBC transfusions starting after month 10 after CTX001 infusion for participants who have not achieved TI12
  12. TDT: Duration of transfusion free in participants who have achieved TI12
  13. TDT: Relative reduction from baseline in annualized volume of RBC transfusions starting after Month 10 after CTX001 infusion for participants who have not achieved TI12
  14. TDT: Iron overload as measured by liver iron concentration (LIC), cardiac iron concentration (CIC), and ferritin for beta-Thalassemia participants
  15. TDT: Proportion of participants receiving iron removal therapy over time
  16. SCD: Proportion of participants who have not experienced any severe vaso-occlusive crises (VOC) for at least 12 consecutive months (VF12)
  17. SCD: Proportion of participants with SCD free from inpatient hospitalization for severe VOCs sustained for at least 12 months (HF12)
  18. SCD: Proportion of participants with at least 90 percent (%), 80%, 75% or 50% reduction in annualized rate of severe VOCs
  19. SCD: Relative change from baseline in annualized rate of severe VOCs
  20. SCD: Duration of severe VOC free in participants who have achieved VF12
  21. SCD: Relative change from baseline in rate of inpatient hospitalizations for severe VOCs
  22. SCD: Relative change from baseline in annualized duration of hospitalization for severe VOCs
  23. SCD: Proportion of participants with sustained HbF ≥20% for at least 3 months
  24. SCD: Proportion of participants with sustained HbF ≥20% for at least 6 months
  25. SCD: Proportion of participants with sustained HbF ≥20% for at least 12 months
  26. SCD: Change in volume of RBCs transfused for SCD-related indications over time
  27. SCD: Change from baseline in reticulocytes/erythrocytes over time
  28. SCD: Change from baseline in lactate dehydrogenase (LDH) over time
  29. SCD: Change from baseline in haptoglobin over time
  30. SCD: Change from baseline in total bilirubin over time
  31. SCD: Change from baseline in indirect bilirubin over time
  32. SCD: Change in SCD-specific PROs over time in participants ≥18 years of age assessed using adult sickle cell quality of life measurement system (ASCQ-Me) (participants from Study 121 and 161 only)
  33. SCD: Change in SCD-specific PROs over time in participants <18 years of age assessed using PedsQL Generic Core SCD module from studies 111,121,141,151 and 161
  34. SCD: Change in PRO over time assessed using 11-point numerical rating scale (NRS)
  35. SCD: Change in PROs over time assessed using Wong Baker FACES pain scale
  36. SCD: Change in PROs over time using face, legs, activity, cry, consolability (FLACC) behavioral pain scale

Eligibility Criteria

Ages Eligible for Study(Child, Adult, Older Adult)
Sexes Eligible for StudyAll
Accepts Healthy VolunteersNo
Inclusion Criteria
Participants (or his or her legally appointed and authorized representative or guardian) must sign and date informed consent form (ICF) and, where applicable, an assent form
Participants must have received CTX001 infusion in a parent study
Exclusion Criteria
There are no exclusion criteria

Contacts and Locations

Sponsors and CollaboratorsVertex Pharmaceuticals Incorporated
Locations
Lucile Packard Children's Hospital | Palo Alto California, United States, 94304Ann & Robert H. Lurie Children's Hospital of Chicago - Hematology | Chicago Illinois, United States, 60611Herbert Irving Pavilion - Hematology | New York New York, United States, 10032New York Presbyterian Hospital - Morgan Stanley Children's Hospital | New York New York, United States, 10032Levine Children's Hospital - Hematology | Charlotte North Carolina, United States, 28203The Children's Hospital of Philadelphia - Hematology | Philadelphia Pennsylvania, United States, 19104St. Jude Children's Research Hospital | Memphis Tennessee, United States, 38105TriStar Medical Group Children's Specialists - Pediatric Oncology | Nashville Tennessee, United States, 37203Methodist Healthcare System of San Antonio, Methodist Hospital, Methodist Children's Hospital | San Antonio Texas, United States, 78229Hopital Universitaire des Enfants Reine Fabiola (HUDERF) - Hematology | Brussels , Belgium, Hospital for Sick Children - Hematology | Toronto , Canada, Toronto General Hospital - Hematology | Toronto , Canada, St. Paul's Hospital - Hematology | Vancouver , Canada, University Hospital Duesseldorf - Department of Pediatric Oncology, Hematology and Clinical Immunology | Düsseldorf , Germany, Center for Pediatric Clinical Studies (CPCS) | Klinik Für Kinder- Und Jugendmedizin , Germany, Regensburg University Hospital, Clinic and Polyclinic for Paediatric and Adolescent Medicine | Regensburg , Germany, IRCSS Ospedale Pediatrico Bambino Gesu - Dipartimento di Onco-Ematologia e Terapia Cellulare e Genica | Rome , Italy, Great Ormond Street Hospital for Children | London , United Kingdom, Hammersmith Hospital - Haematology Dept | London , United Kingdom, University College London Hospital NHS Foundation - Main | London , United Kingdom,