This is a pilot phase II open label study testing the activity and feasibility of utilizing a regimen to boost the immune system in order to treat AML, ALL, blast phase CML, and MDS relapse after allogeneic transplantation. The regimen is a step-wise use of withdrawal of immunosuppression, cytoreduction if needed, administration of granulocyte-macrophage colony-stimulating factor (GM-CSF) and pegylated interferon (IFN) α-2b to patients who relapsed after an allogeneic transplant and will assess efficacy.~Relapse is the major problem following allogeneic hematopoietic progenitor cell transplants. There is currently no standard way to treat leukemia that relapsed after transplant, and patients have a poor prognosis.~A retrospective analysis of patients treated at Emory showed that administration of GM-CSF and interferon-alpha-2b was well-tolerated and affected long-term remissions in a small number of relapsed patients (after allogeneic transplant). Pre-clinical and clinical data from ours and other centers showed that relapsed leukemic blasts have down-regulation of co-stimulatory molecules and a tendency to evade the immune system. Cytokines can up-regulate co-stimulatory molecules on leukemic blasts and have been shown to increase the cytotoxicity of T-cells. This effect may be beneficial as a graft vs. leukemia effect for patients with relapse after allogeneic transplant.
The relapse of acute leukemia, MDS and blast phase CML after allogeneic transplantation affects approximately 1/3 to 1/2 of all transplant recipients and is the main cause of treatment failure. There is currently no effective standard treatment for this condition.~This study will test the activity and feasibility of using a regimen to boost the immune system in order to treat AML, ALL, blast phase CML, and MDS relapse after allogeneic transplantation.