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

August 7, 2026 updated by: Vertex Pharmaceuticals Incorporated

A Long-term Follow-up Study of Subjects With β-thalassemia or Sickle Cell Disease Treated With Autologous CRISPR-Cas9 Modified Hematopoietic Stem Cells (CTX001)

This is a multi-site, open- label rollover study to evaluate the long-term safety and efficacy of CTX001 in pediatric and adult participants who received CTX001 in parent studies 111 (NCT03655678) 141 (NCT05356195) or 161 (NCT05477563) (transfusion-dependent β-thalassemia [TDT] studies) or Study 121 (NCT03745287) or 151 (NCT05329649) or 161(NCT05477563) (severe sickle cell disease [SCD] studies).

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Enrolling by invitation

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
160

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

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

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

2 years and older (Child, Adult, Older Adult)

Accepts Healthy Volunteers

No

Study Population

All subjects who complete or discontinue the parent study (CTX001-111 or CTX001-121 or VX21-CTX001-141 or VX21-CTX001-151) after CTX001 infusion will be enrolled in the long-term follow-up study.

Description

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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: 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.
Other Names:
  • Exagamglogene autotemcel
  • Exa-cel

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Time Frame
New malignancies
Time Frame: Signing of informed consent up to 15 years post CTX001 infusion
Signing of informed consent up to 15 years post CTX001 infusion
New or worsening hematologic disorders
Time Frame: Signing of informed consent up to 15 years post CTX001 infusion
Signing of informed consent up to 15 years post CTX001 infusion
All-cause mortality
Time Frame: Signing of informed consent up to 15 years post CTX001 infusion
Signing of informed consent up to 15 years post CTX001 infusion
Serious adverse events (SAEs)
Time Frame: Signing of informed consent up to 15 years post CTX001 infusion
Signing of informed consent up to 15 years post CTX001 infusion
CTX001-related adverse events (AEs)
Time Frame: Signing of informed consent up to 15 years post CTX001 infusion
Signing of informed consent up to 15 years post CTX001 infusion

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Time Frame
TDT and SCD: Proportion of alleles with intended genetic modification present in peripheral blood over time
Time Frame: Up to 15 years post CTX001 infusion
Up to 15 years post CTX001 infusion
SCD: Relative change from baseline in annualized rate of severe VOCs
Time Frame: From 60 days after last RBC transfusion up to 15 years post-CTX001 infusion
From 60 days after last RBC transfusion up to 15 years post-CTX001 infusion
SCD: Relative change from baseline in rate of inpatient hospitalizations for severe VOCs
Time Frame: From 60 days after last RBC transfusion up to 15 years post-CTX001 infusion
From 60 days after last RBC transfusion up to 15 years post-CTX001 infusion
SCD: Relative change from baseline in annualized duration of hospitalization for severe VOCs
Time Frame: From 60 days after last RBC transfusion up to 15 years post-CTX001 infusion
From 60 days after last RBC transfusion up to 15 years post-CTX001 infusion
SCD: Change in volume of RBCs transfused for SCD-related indications over time
Time Frame: Up to 15 years post CTX001 infusion
Up to 15 years post CTX001 infusion
SCD: Change from baseline in reticulocytes/erythrocytes over time
Time Frame: From baseline up to 15 years post CTX001 infusion
From baseline up to 15 years post CTX001 infusion
SCD: Change from baseline in lactate dehydrogenase (LDH) over time
Time Frame: From baseline up to 15 years post CTX001 infusion
From baseline up to 15 years post CTX001 infusion
SCD: Change from baseline in haptoglobin over time
Time Frame: From baseline up to 15 years post CTX001 infusion
From baseline up to 15 years post CTX001 infusion
SCD: Change from baseline in total bilirubin over time
Time Frame: From baseline up to 15 years post CTX001 infusion
From baseline up to 15 years post CTX001 infusion
SCD: Change from baseline in indirect bilirubin over time
Time Frame: From baseline up to 15 years post CTX001 infusion
From baseline up to 15 years post CTX001 infusion
SCD: Change in PRO over time assessed using 11-point numerical rating scale (NRS)
Time Frame: Up to 5 years post CTX001 infusion
Up to 5 years post CTX001 infusion
SCD: Change in PROs over time assessed using Wong Baker FACES pain scale
Time Frame: Up to 5 years post CTX001 infusion
Up to 5 years post CTX001 infusion
SCD: Change in PROs over time using face, legs, activity, cry, consolability (FLACC) behavioral pain scale
Time Frame: Up to 5 years post CTX001 infusion
Up to 5 years post CTX001 infusion
TDT and SCD: Total Hemoglobin (Hb) concentration over time
Time Frame: Up to 15 years post CTX001 infusion
Up to 15 years post CTX001 infusion
TDT and SCD: Fetal Hemoglobin (HbF) concentration over time
Time Frame: Up to 15 years post CTX001 infusion
Up to 15 years post CTX001 infusion
TDT and SCD: Proportion of alleles with intended genetic modification present in CD34+ cells of the bone marrow over time
Time Frame: Up to 15 years post CTX001 infusion
Up to 15 years post CTX001 infusion
TDT and SCD: Change in PROs over time in participants <18 years assessed using pediatric quality of life inventory (PedsQL) Core
Time Frame: Up to 5 years post CTX001 infusion
Up to 5 years post CTX001 infusion
TDT: Proportion of participants achieving transfusion independence for at least 12 consecutive months (TI12)
Time Frame: From 60 days after last RBC transfusion up to 15 years post-CTX001 infusion
From 60 days after last RBC transfusion up to 15 years post-CTX001 infusion
TDT: Proportion of participants achieving transfusion independence for at least 6 consecutive months (TI6)
Time Frame: From 60 days after last RBC transfusion up to 15 years post-CTX001 infusion
From 60 days after last RBC transfusion up to 15 years post-CTX001 infusion
TDT: Duration of transfusion free in participants who have achieved TI12
Time Frame: From 60 days after last RBC transfusion up to 15 years post CTX001 infusion
From 60 days after last RBC transfusion up to 15 years post CTX001 infusion
SCD: Proportion of participants who have not experienced any severe vaso-occlusive crises (VOC) for at least 12 consecutive months (VF12)
Time Frame: From 60 days after last RBC transfusion up to 15 years post-CTX001 infusion
From 60 days after last RBC transfusion up to 15 years post-CTX001 infusion
SCD: Proportion of participants with SCD free from inpatient hospitalization for severe VOCs sustained for at least 12 months (HF12)
Time Frame: From 60 days after last RBC transfusion up to 15 years post-CTX001 infusion
From 60 days after last RBC transfusion up to 15 years post-CTX001 infusion
SCD: Proportion of participants with at least 90 percent (%), 80%, 75% or 50% reduction in annualized rate of severe VOCs
Time Frame: From 60 days after last RBC transfusion up to 15 years post-CTX001 infusion
From 60 days after last RBC transfusion up to 15 years post-CTX001 infusion
SCD: Duration of severe VOC free in participants who have achieved VF12
Time Frame: From 60 days after last RBC transfusion up to 15 years post CTX001 infusion
From 60 days after last RBC transfusion up to 15 years post CTX001 infusion
SCD: Proportion of participants with sustained HbF ≥20% for at least 3 months
Time Frame: From 60 days after last RBC transfusion up to 15 years post-CTX001 infusion
From 60 days after last RBC transfusion up to 15 years post-CTX001 infusion
SCD: Proportion of participants with sustained HbF ≥20% for at least 6 months
Time Frame: From 60 days after last RBC transfusion up to 15 years post-CTX001 infusion
From 60 days after last RBC transfusion up to 15 years post-CTX001 infusion
SCD: Proportion of participants with sustained HbF ≥20% for at least 12 months
Time Frame: From 60 days after last RBC transfusion up to 15 years post-CTX001 infusion
From 60 days after last RBC transfusion up to 15 years post-CTX001 infusion
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
Time Frame: From Month 10 up to 15 years post-CTX001 infusion
From Month 10 up to 15 years post-CTX001 infusion
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
Time Frame: From Month 10 up to 15 years post-CTX001 infusion
From Month 10 up to 15 years post-CTX001 infusion
TDT: Iron overload as measured by liver iron concentration (LIC), cardiac iron concentration (CIC), and ferritin for beta-Thalassemia participants
Time Frame: Up to 8 years post CTX001 infusion for LIC; up to 5 years post CTX001 infusion for CIC and up to 15 years post CTX001 infusion for ferritin
Up to 8 years post CTX001 infusion for LIC; up to 5 years post CTX001 infusion for CIC and up to 15 years post CTX001 infusion for ferritin
TDT: Proportion of participants receiving iron removal therapy over time
Time Frame: Up to 15 years post CTX001 infusion
Up to 15 years post CTX001 infusion
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
Time Frame: Up to 5 years post CTX001 infusion
Up to 5 years post CTX001 infusion
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
Time Frame: Up to 5 years post CTX001 infusion
Up to 5 years post CTX001 infusion
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
Time Frame: Up to 5 years post CTX001 infusion
Up to 5 years post CTX001 infusion
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)
Time Frame: Up to 5 years post CTX001 infusion
Up to 5 years post CTX001 infusion
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
Time Frame: Up to 5 years post CTX001 infusion
Up to 5 years post CTX001 infusion

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Vertex Pharmaceuticals Incorporated

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
CRISPR Therapeutics

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
January 20, 2021

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
September 30, 2039

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
September 30, 2039

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
December 20, 2019

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
December 20, 2019

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
December 23, 2019

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
August 11, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 7, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
August 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • VX18-CTX001-131
  • 2024-512654-19-00 (Other Identifier: EU CT Number)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Details on Vertex data sharing criteria and process for requesting access can be found at: https://www.vrtx.com/our-science/clinical-trials-data-sharing/

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

Yes

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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