NCT07183878

Venetoclax-Enhanced BUCY vs. Standard BUCY Conditioning in High-Risk AML and MDS Patients Undergoing Allo-HSCT (Ven-BUCY Study)

A Prospective, Multicenter, Randomized Controlled Study Comparing Venetoclax-Enhanced BUCY With Standard BUCY Conditioning in High-Risk AML and MDS Patients Undergoing Allogeneic Hematopoietic Stem Cell Transplantation

• Status: Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 138 (estimated)
• Sponsor: First Affiliated Hospital of Zhejiang University · Academic / Other
• Sex: All
• Age: 12 Years – 60 Years
• Healthy volunteers: Not accepted

Summary

This is a prospective, multicenter, randomized controlled trial designed to evaluate the efficacy and safety of venetoclax-enhanced BUCY (Ven-BUCY) conditioning compared to the standard BUCY regimen in patients with high-risk acute myeloid leukemia (AML) or myelodysplastic syndromes (MDS) undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). Eligible participants aged 12 to 60 years will be randomized 1:1 to receive either Ven-BUCY or standard BUCY conditioning. The primary endpoint is relapse-free survival (RFS) at two years post-transplant. Secondary outcomes include overall survival, relapse rate, non-relapse mortality, measurable residual disease (MRD), and treatment-related adverse events. The study aims to improve post-transplant outcomes by deepening disease remission through the addition of venetoclax, a BCL-2 inhibitor known to target leukemia stem cells and enhance chemotherapy sensitivity.

Detailed description

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains the only curative therapy for high-risk acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). However, post-transplant relapse remains the leading cause of treatment failure, especially among patients receiving matched sibling or unrelated donor transplants. While myeloablative conditioning (MAC) regimens like BUCY (busulfan + cyclophosphamide) offer stronger anti-leukemic effects compared to reduced-intensity regimens, the relapse rate in high-risk myeloid neoplasms remains unacceptably high, partly due to residual leukemia stem cells (LSCs). Venetoclax, a selective BCL-2 inhibitor, has shown synergistic effects when combined with hypomethylating agents or intensive chemotherapy. It improves remission depth and targets chemotherapy-resistant LSCs. Emerging data suggest that venetoclax may also enhance graft-versus-leukemia (GVL) effects without significantly increasing the risk of graft-versus-host disease (GVHD). This investigator-initiated, open-label, two-arm, randomized controlled trial will enroll 138 patients aged 12-60 years with high-risk AML or MDS across six transplant centers in China. Patients will be stratified by disease (AML vs. MDS) and randomized (1:1) to receive either: Standard BUCY regimen: Busulfan (0.8 mg/kg q6h on day -7 to -4), Cyclophosphamide (60 mg/kg/day on day -3 and -2), and MeCCNU (250 mg/m² on day -1), with optional ATG for donors/recipients \>40 years. Ven-BUCY regimen: Venetoclax (400 mg/day or 360 mg/m²/day from day -14 to -8) in addition to the standard BUCY components, with similar ATG guidance. Antifungal prophylaxis and venetoclax dose adjustment (e.g., to 100 mg with posaconazole) will follow local guidelines. Patients will be followed weekly during the first month post-transplant, monthly for 6 months, and every 3 months thereafter until 3 years post-enrollment. The primary endpoint is 2-year relapse-free survival (RFS). Secondary endpoints include overall survival (OS), non-relapse mortality (NRM), relapse rate, MRD clearance, and adverse events graded by CTCAE v5.0. This study seeks to determine whether adding venetoclax to a standard myeloablative regimen can enhance anti-leukemic efficacy and improve long-term outcomes without increasing transplant-related toxicity.

Conditions

• Acute Myeloid Leukemia
• High-Risk Acute Myeloid Leukemia
• Myelodysplastic Syndromes
• High-Risk Myelodysplastic Syndromes

Interventions

Type	Name	Description
DRUG	Venetoclax	Venetoclax is administered orally at 400 mg/day for participants ≥14 years or 360 mg/m²/day for those aged 12-14 years, from day -14 to -8 before allogeneic hematopoietic stem cell transplantation (allo-HSCT). Dose is adjusted to 100 mg/day (or 90 mg/m²/day for pediatric patients) if used with strong CYP3A4 inhibitors such as posaconazole.
OTHER	None-placebo	Participants in this arm will not receive venetoclax as part of their conditioning regimen. They will undergo standard myeloablative conditioning with BUCY (busulfan, cyclophosphamide, and MeCCNU), prior to allogeneic hematopoietic stem cell transplantation. This arm serves as the active comparator to evaluate the addition of venetoclax in the experimental arm.

Timeline

• Start date: 2025-08-20
• Primary completion: 2027-08-20
• Completion: 2028-08-20
• First posted: 2025-09-19
• Last updated: 2025-09-19

Locations

1 site across 1 country: China