CompletedPhase 2/3

A Safety and Efficacy Study Evaluating CTX001 in Participants With Transfusion-Dependent β-Thalassemia

United States, Canada, Germany59 participantsStarted 2018-09-14

Plain-language summary

This is a single-arm, open-label, multi-site, single-dose Phase 1/2/3 study in participans with transfusion-dependent β-thalassemia (TDT). The study will evaluate the safety and efficacy of autologous CRISPR-Cas9 Modified CD34+ Human Hematopoietic Stem and Progenitor Cells (hHSPCs) using CTX001.

Who can participate

Age range

12 Years – 35 Years

Sex

ALL

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Inclusion criteria

. Documented homozygous β-thalassemia 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/kg/year or ≥10 units/year of packed RBC transfusions in the prior 2 years before signing the consent or the last rescreening for patients going through re-screening

Questions worth asking your doctor

Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.

1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?

Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.

Questions for the trial coordinator

The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.

1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?

A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.

What they're measuring

Proportion of participants achieving transfusion independence for at least 12 consecutive months (TI12)

Timeframe: From 60 days after last RBC transfusion up to 24 months post-CTX001 infusion]

Proportion of participants with engraftment (first day of 3 consecutive measurements of absolute neutrophil count [ANC] ≥500/µL on three different days)

Timeframe: Within 42 days after CTX001 infusion

Time to neutrophil and platelet engraftment

Timeframe: Days post-infusion to engraftment

Frequency and severity of collected adverse events (AEs)

Timeframe: Signing of informed consent through Month 24 visit

Incidence of transplant-related mortality (TRM)

Timeframe: Baseline (pre-transfusion) to 100 days and 1 year post-CTX001 infusion

All-cause mortality

Timeframe: Signing of informed consent through Month 24 visit

Trial details

NCT IDNCT03655678

SponsorVertex Pharmaceuticals Incorporated

Sponsor typeINDUSTRY

Study typeINTERVENTIONAL

Primary completion2025-11-13

View on ClinicalTrials.gov More Beta-Thalassemia trials

Who can participate

Age range

12 Years – 35 Years

Sex

ALL

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Inclusion criteria

. Documented homozygous β-thalassemia 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/kg/year or ≥10 units/year of packed RBC transfusions in the prior 2 years before signing the consent or the last rescreening for patients going through re-screening

What they're measuring

Proportion of participants achieving transfusion independence for at least 12 consecutive months (TI12)

Timeframe: From 60 days after last RBC transfusion up to 24 months post-CTX001 infusion]

Proportion of participants with engraftment (first day of 3 consecutive measurements of absolute neutrophil count [ANC] ≥500/µL on three different days)

Timeframe: Within 42 days after CTX001 infusion

Time to neutrophil and platelet engraftment

Timeframe: Days post-infusion to engraftment

Frequency and severity of collected adverse events (AEs)

Timeframe: Signing of informed consent through Month 24 visit

Incidence of transplant-related mortality (TRM)

Timeframe: Baseline (pre-transfusion) to 100 days and 1 year post-CTX001 infusion

All-cause mortality

Timeframe: Signing of informed consent through Month 24 visit