Low Risk of Chronic Graft Versus Host Disease and Relapse Associated with T-Cell Depleted Peripheral Blood Stem Cell Transplantation for Acute Myeloid Leukemia in First Remission: Results of the Blood and Marrow Transplant Clinical Trials Network (BMT CTN) Protocol 0303

摘要

Graft versus host disease (GVHD) is most effectively prevented by ex vivo T cell depletion (TCD) of the allograft but its role in the treatment of patients undergoing allogeneic hematopoietic cell transplantation (HCT) for acute myeloid leukemia (AML) in complete remission (CR) remains unclear. We therefore performed a Phase 2 single arm multi-center study to evaluate the role of TCD in AML patients in CR1 or CR2 up to the age of 65 years. The primary objective was to achieve a disease-free survival (DFS) rate at 6 months post transplant that exceeded 75%. 44 patients with AML in CR1 (N=37) or CR2 (N=7) with a median age of 48.5 years (range 21–59) received myeloablative chemotherapy and fractionated total body irradiation (TBI, 1,375cGy) followed by immunomagnetically selected CD34-enriched, T-cell depleted allografts from HLA-identical siblings. No pharmacological GVHD prophylaxis was given. All patients engrafted. The incidence of acute GVHD grades 2–4 was 22.7%. The incidence of extensive chronic GVHD was 6.8% at 24 months. The relapse rate for patients in CR1 at 36 months was 17.4%. With a median follow up of 34 months, disease free survival (DFS) for all patients at 6 months was 82%. DFS for pts in CR1 was 72.8% and 58% at 12 and 36 months, respectively. HCT following myeloablative chemoradiotherapy can be performed in a multi-center setting using a uniform method of TCD resulting in a low risk of extensive chronic GVHD and relapse for pts with AML in CR1.