Imatinib Mesylate With or Without Interferon Alfa or Cytarabine Compared With Interferon Alfa Followed by Donor Stem Cell Transplant in Treating Patients With Newly Diagnosed Chronic Phase Chronic Myelogenous Leukemia

RATIONALE: Giving chemotherapy before a donor bone marrow transplant helps stop the growth of cancer cells. It also helps stop the patient's immune system from rejecting the donor's stem cells. Also, imatinib mesylate may stop the growth of cancer cells by blocking the enzymes needed for cancer cell growth. Interferon alfa may interfere with the growth of cancer cells and slow the growth of cancer. When the healthy stem cells from a donor are infused into the patient they may help the patient's bone marrow make stem cells, red blood cells, white blood cells, and platelets. It is not yet known which treatment regimen is most effective in treating chronic phase chronic myelogenous leukemia. PURPOSE: This randomized phase III trial is studying imatinib mesylate with or without interferon alfa or cytarabine to see how well it works compared with interferon alfa followed by donor stem cell transplant in treating patients with newly diagnosed chronic phase chronic myelogenous leukemia.