TBF Conditioning Regimen for Haploidentical Stem Cell Transplantation in Elderly AML Patients in First Complete Remission (TBF-AML)

A Single-Center, Prospective, Single-Arm Clinical Study Evaluating the Efficacy and Safety of Thiotepa, Busulfan, and Fludarabine (TBF) Conditioning Regimen in Haploidentical Peripheral Blood Stem Cell Transplantation for Elderly Acute Myeloid Leukemia Patients in First Complete Remission

Acute myeloid leukemia (AML) is a serious blood cancer that mainly affects older adults. For patients who achieve their first complete remission (CR1), allogeneic hematopoietic stem cell transplantation (HSCT) may provide a chance for long-term survival. However, relapse after transplantation remains a major challenge.

This study aims to evaluate the effectiveness and safety of a conditioning regimen that combines thiotepa, busulfan, and fludarabine (TBF) before haploidentical peripheral blood stem cell transplantation (haplo-PBSCT) in elderly patients with AML in first complete remission.

Eligible patients will receive the TBF conditioning regimen followed by stem cell transplantation from a partially matched donor. Participants will be followed to assess relapse-free survival, overall survival, transplant-related complications, and infections.

The results of this study may help improve treatment strategies and outcomes for elderly AML patients undergoing transplantation.

Study Overview

Detailed Description

Acute myeloid leukemia (AML) is a heterogeneous hematologic malignancy with increasing incidence in older populations. Despite achieving first complete remission (CR1) after induction chemotherapy, elderly patients remain at high risk of relapse and have poor long-term outcomes.

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is considered a potentially curative treatment for AML. With the development of reduced-intensity conditioning regimens and haploidentical transplantation strategies, more elderly patients are now eligible for transplantation. However, relapse after transplantation remains a major limitation.

The conditioning regimen plays a critical role in determining transplant outcomes. The combination of thiotepa, busulfan, and fludarabine (TBF) has been proposed to enhance anti-leukemic activity while maintaining acceptable toxicity. Previous retrospective and registry-based studies suggest that TBF conditioning may reduce relapse risk compared with conventional regimens, but prospective data in elderly AML patients, especially in Asian populations, remain limited.

This study is a single-center, prospective, single-arm clinical trial designed to evaluate the efficacy and safety of the TBF conditioning regimen in elderly AML patients in first complete remission undergoing haploidentical peripheral blood stem cell transplantation (haplo-PBSCT).

Eligible patients aged 55-75 years with AML in CR1 or CRi will receive a conditioning regimen consisting of thiotepa (day -7), busulfan (days -4 and -3), and fludarabine (days -6 to -2), followed by infusion of donor stem cells on day 0.

The primary endpoint is 1-year relapse-free survival (RFS), defined as the time from transplantation to relapse or death from any cause. Secondary endpoints include overall survival, incidence of acute and chronic graft-versus-host disease (GVHD), non-relapse mortality, hematopoietic engraftment, donor chimerism, and infection rates.

Participants will be followed regularly after transplantation with clinical assessments, laboratory tests, and bone marrow evaluations according to protocol-defined schedules.

The findings from this study are expected to provide prospective evidence for the use of TBF conditioning in elderly AML patients and support optimization of transplantation strategies in this population.

Study Type

Interventional

Enrollment (Estimated)

93

Phase

  • Not Applicable

Contacts and Locations

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

Study Contact

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

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age 55 to 75 years
  • Diagnosed with acute myeloid leukemia (AML) based on morphology, immunophenotyping, cytogenetics, or molecular testing
  • First complete remission (CR1) or complete remission with incomplete hematologic recovery (CRi)
  • Eligible for haploidentical hematopoietic stem cell transplantation
  • Availability of a suitable haploidentical donor
  • ECOG performance status 0-2
  • Adequate organ function:

    • Left ventricular ejection fraction ≥50%
    • Oxygen saturation >92% on room air
    • Serum creatinine ≤1.5 × upper limit of normal (ULN)
    • Total bilirubin ≤1.5 × ULN
    • AST and ALT ≤2.0 × ULN
    • DLCO ≥40% and FEV1 ≥50%
  • Ability to understand and sign informed consent

Exclusion Criteria:

  • Secondary AML (including AML evolving from myelodysplastic syndrome or therapy-related AML)
  • Active, uncontrolled infection
  • Severe uncontrolled systemic disease (e.g., unstable cardiovascular disease, recent stroke, or severe organ dysfunction)
  • HIV infection
  • Active hepatitis B or C requiring antiviral treatment
  • Pregnant or breastfeeding women
  • Known hypersensitivity to study drugs

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Arms Back to Arms and Interventions * Required * § Required if Study Start Date is on or after Janu
Participants will receive a conditioning regimen consisting of thiotepa, busulfan, and fludarabine (TBF) followed by haploidentical peripheral blood stem cell transplantation. Thiotepa is administered on day -7, busulfan on days -4 and -3, and fludarabine on days -6 to -2. Donor stem cells are infused on day 0. Standard graft-versus-host disease prophylaxis and supportive care will be provided according to institutional guidelines.
Thiotepa is administered intravenously at a dose of 5 mg/kg on day -7 as part of the TBF conditioning regimen prior to haploidentical peripheral blood stem cell transplantation.
Busulfan is administered intravenously at a dose of 3.2 mg/kg on days -4 and -3 as part of the TBF conditioning regimen.
Fludarabine is administered intravenously at a dose of 30 mg/m² daily from day -6 to day -2 as part of the conditioning regimen.
Haploidentical peripheral blood stem cell transplantation is performed on day 0 following conditioning. Donor stem cells are infused, and standard graft-versus-host disease prophylaxis and supportive care are provided according to institutional protocols.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
1-year Relapse-Free Survival (RFS)
Time Frame: 12 months after transplantation
Relapse-free survival (RFS) is defined as the time from transplantation to the first occurrence of disease relapse or death from any cause. Patients who are alive without relapse at the last follow-up will be censored.
12 months after transplantation

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Overall Survival (OS)
Time Frame: 12 months after transplantation
Overall survival is defined as the time from transplantation to death from any cause. Patients alive at last follow-up will be censored.
12 months after transplantation
Incidence of Acute Graft-Versus-Host Disease (aGVHD)
Time Frame: Up to 180 days after transplantation
The cumulative incidence of grade I-IV and grade III-IV acute graft-versus-host disease within 180 days after transplantation, assessed according to standard criteria.
Up to 180 days after transplantation
Incidence of Chronic Graft-Versus-Host Disease (cGVHD)
Time Frame: 12 months after transplantation
The cumulative incidence of all-grade and moderate-to-severe chronic graft-versus-host disease, assessed according to NIH consensus criteria.
12 months after transplantation
Non-Relapse Mortality (NRM)
Time Frame: 12 months after transplantation
Non-relapse mortality is defined as death without evidence of disease relapse. Relapse is treated as a competing event.
12 months after transplantation

Collaborators and Investigators

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

Investigators

  • Principal Investigator: Xianmin Song, Shanghai general hospital, Shanghai Jiao Tong University School of Medicine

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 (Estimated)

June 1, 2026

Primary Completion (Estimated)

June 1, 2029

Study Completion (Estimated)

June 1, 2030

Study Registration Dates

First Submitted

April 26, 2026

First Submitted That Met QC Criteria

April 26, 2026

First Posted (Actual)

May 4, 2026

Study Record Updates

Last Update Posted (Actual)

May 4, 2026

Last Update Submitted That Met QC Criteria

April 26, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data (IPD) will not be shared due to patient privacy concerns and institutional data protection policies. De-identified data may be available from the corresponding investigator upon reasonable request and with appropriate institutional approvals.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

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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