VABu Conditioning in Elderly AML HSCT

Efficacy and Safety of the VABu Conditioning Regimen in Elderly Patients With Acute Myeloid Leukemia Undergoing Hematopoietic Stem Cell Transplantation: An Open-Label, Multicenter, Single-Arm Clinical Study

This is an open-label, multi-center, single-arm clinical study evaluating the efficacy and safety of the VABu conditioning regimen in elderly patients (≥60 years) with acute myeloid leukemia (AML) undergoing allogeneic hematopoietic stem cell transplantation (HSCT).

The VABu regimen consists of Venetoclax, Azacitidine, Semustine, Cytarabine, and Busulfan. All enrolled participants will receive the VABu regimen as conditioning therapy prior to HSCT.

The study aims to enroll 20 participants from multiple centers in China. The primary objectives are to evaluate the overall response rate, cumulative relapse rate, overall survival, graft-versus-host disease (GVHD)-free relapse-free survival (GRFS), non-relapse mortality (NRM), incidence of acute and chronic GVHD, and reactivation rates of cytomegalovirus (CMV) and Epstein-Barr virus (EBV). Safety outcomes include treatment-related toxicities, such as bone marrow suppression, infection, and organ dysfunction.

Study Overview

• Status: Recruiting
• Conditions: Acute Myeloid Leukemia (AML); Allogeneic Hematopoietic Stem Cell Transplantation Recipient
• Intervention / Treatment: Drug: VaBU

• Study Type: Interventional
• Enrollment (Estimated): 20
• Phase: Phase 2; Phase 3

Contacts and Locations

• Study Contact: Name: Huiying Qiu, M.D.; Phone Number: +8613912792913 +8618151578096; Email: mumukongxin@hotmail.com

Study Locations

• China
  • Jiangsu
    • Suzhou, Jiangsu, China, 215000
      • Recruiting
      • The First Affiliated Hospital of Soochow University
      • Contact: Xin Kong; Phone Number: 67781856; Email: mumukongxin@hotmail.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Age ≥ 60 years.
2. Confirmed diagnosis of acute myeloid leukemia (AML) according to WHO classification, with intermediate or high-risk prognosis.
3. Previous response to Venetoclax-based therapy.
4. Planned to undergo allogeneic hematopoietic stem cell transplantation (HSCT).
5. Donor availability: Related donor matched at least 5/10 at HLA-A, -B, -C, -DQB1, and -DRB1; OR unrelated donor matched at least 8/10 at the same loci.
6. Hematopoietic Cell Transplantation-Specific Comorbidity Index (HCT-CI) score ≤ 4.
7. ECOG performance status 0-2.
8. Adequate organ function as defined by: Creatinine ≤ 1.5 × ULN or creatinine clearance ≥ 45 mL/min (Cockcroft-Gault formula or 24-hour urine collection)； AST ≤ 3.0 × ULN and ALT ≤ 3.0 × ULN； Total bilirubin ≤ 1.5 × ULN； Left ventricular ejection fraction (LVEF) > 50%； Baseline oxygen saturation > 92%； DLCO ≥ 40% and FEV1 ≥ 50%；
9. Ability to understand and provide written informed consent.

Exclusion Criteria:

1. Age < 60 years.
2. Poor response to prior Venetoclax-based therapy.
3. Unstable systemic disease (unstable angina, myocardial infarction, cerebrovascular accident within 3 months; NYHA Class III-IV heart failure; severe arrhythmia; pulmonary hypertension).
4. Active uncontrolled infection or active bleeding in vital organs.
5. CNS symptoms grade ≥ 2 requiring treatment.
6. Major organ surgery within 6 weeks.
7. History of malignant disease other than AML within 5 years.
8. History of thrombosis, embolism, or cerebral hemorrhage within 1 year.
9. ECOG performance status > 2.
10. HCT-CI score > 4.
11. Organ failure meeting specified criteria.
12. Known HIV, active HBV, or active HCV infection.
13. History of autoimmune disease requiring systemic immunosuppressive therapy.
14. Pregnancy, breastfeeding, or unwillingness to use effective contraception in patients of childbearing potential.
15. Drug abuse or chronic alcoholism.
16. Psychiatric disorder or other condition compromising informed consent or compliance.
17. Any other condition making the patient unsuitable for study participation in the investigator's judgment.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: VaBU

Drug: VaBU; The VABu conditioning regimen is administered prior to allogeneic hematopoietic stem cell transplantation (HSCT). The regimen consists of the following drugs administered sequentially: Venetoclax: 600 mg/m² orally once daily on days -10 to -5. Azacitidine: 75 mg/m² subcutaneously once daily on days -10 to -6. Semustine: 250 mg/m² orally once on day -10. Cytarabine: 2 g/m² intravenously once daily on day -1. Busulfan: 0.8 mg/kg intravenously every 6 hours on days -4 to -2 (total of 12 doses). The conditioning regimen is completed before HSCT. Dose adjustments may be made based on toxicity, concomitant medications (especially CYP3A4 inhibitors), and individual patient tolerance.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Progression-Free Survival (PFS)	Progression-free survival is defined as the time from the date of transplantation to the date of disease progression, relapse, or death from any cause, whichever occurs first. Participants who are alive without progression or relapse at the last follow-up are censored.	1 year and 2 years post-transplantation

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Overall Survival (OS)	Overall survival is defined as the time from the date of transplantation to the date of death from any cause. Participants who are alive at the last follow-up are censored.	1 year and 2 years post-transplantation
Cumulative Incidence of Relapse (CIR)		1 year, 2 years
Non-relapse Mortality (NRM)		Day 100, 1 year, 2 years
GVHD-free Relapse-free Survival (GRFS)		1 year, 2 years
Incidence of Acute GVHD		Day 100, Day 180
Incidence of Chronic GVHD		1 year, 2 years
CMV Reactivation Rate		1 year
EBV Reactivation Rate	include EBV-related post-transplant lymphoproliferative disorder (PTLD)	1 year
Engraftment Rate		Day 30
Safety and Tolerability (TEAEs)		Treatment period to 30 days post-treatment

Collaborators and Investigators

• Sponsor: The First Affiliated Hospital of Soochow University
• Collaborators: Henan Cancer Hospital; Shenzhen People's Hospital; Huai'an Second People's Hospital and the Affiliated Huai'an Hospital of Xuzhou Medical University; Suzhou Hongci Hematology Hospital, Suzhou, China

Study record dates

Study Major Dates

• Study Start (Estimated): May 7, 2026
• Primary Completion (Estimated): August 15, 2027
• Study Completion (Estimated): August 15, 2027

Study Registration Dates

• First Submitted: May 7, 2026
• First Submitted That Met QC Criteria: May 7, 2026
• First Posted (Actual): May 13, 2026

Study Record Updates

• Last Update Posted (Actual): May 14, 2026
• Last Update Submitted That Met QC Criteria: May 12, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Acute Myeloid Leukemia; Elderly; Hematopoietic Stem Cell Transplantation; Venetoclax; Busulfan; Preconditioning
• Additional Relevant MeSH Terms: Neoplasms; Neoplasms by Histologic Type; Hematologic Diseases; Leukemia, Myeloid; Leukemia; Hemic and Lymphatic Diseases; Leukemia, Myeloid, Acute
• Other Study ID Numbers: ZSQ003

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: This is a small investigator-initiated study (n=20) conducted in China. Due to institutional policies regarding patient privacy protection and the lack of established infrastructure for individual participant data sharing, IPD will not be made available.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No