The present invention relates to methods and compositions for preventing and/or treating various conditions in a patient, including for example, T-cell lymphoblastic leukemia and lymphoma as well as neurodegenerative diseases, such as for example, Alzheimers disease. In one preferred embodiment of the invention, such methods include providing a patient with an effective amount of a combination of a NOTCH-1 inhibitor and glucocorticoid. The present invention further encompasses methods for increasing the efficacy of, and mitigating resistance to, glucocorticoids in the treatment of T-cell lymphoblastic leukemia and lymphoma, which generally include providing a patient with an effective amount of one or more NOTCH-1 inhibitors.
