Chronic myeloid leukemia is a serious disease which is characterized by progression from relatively quiescent stages of the disease to an aggressive phase. Although now there is highly successful medical therapy known as Gleevec (Imatinib), the treatment is not always successful and patients do develop resistance. Those patients have limited treatment options. We are developing a gene therapy model of treatment for this disease using pseudoviral particles to insert molecules of genetic material which would not allow the harmful genes causing the leukemia to function.