Relapse of Hematologic Malignancy After Allogeneic Hematopoietic Transplantation

Allogeneic hematopoietic transplantation is an effective, potentially curative treatment for hematologic malignancies. Relapse post-transplant has been most extensively studied in patients with chronic myeloid leukemia. Over 70% of patients with minimal residual disease (MRD) or relapsing into a chronic phase achieve a durable complete remission. Allogeneic hematopoietic transplantation is a major treatment for acute myeloid leukemia (AML)/myelodysplastic syndrome (MDS). Chemotherapy generally produces only short-term responses in AML/MDS patients relapsing post-transplant and the best results have been achieved when a donor lymphocyte infusion (DLI) or a second allogeneic transplant is performed to consolidate a chemotherapy-induced response. There has been limited experience with the treatment of relapse post-transplant in patients with lymphomas, Hodgkin disease, chronic lymphocytic leukemia (CLL), and multiple myeloma. Azacitidine has direct antileukemia effects and may favorably enhance graft-versus-leukemia (GVL) effects against myeloid malignancies. Peptide vaccines may improve the GVL effect with little toxicity.