Detection of minimal residual disease: Progress in understanding DNA changes in acute leukemia has already provided an improved and highly sensitive test for detecting leukemia cells after treatment, even when so few are present that they cannot be found by routine bone marrow tests. Tests such as the polymerase chain reaction (PCR) can identify acute leukemia cells based on their gene translocations or rearrangements. This test can find one leukemic cell among a million normal cells. A PCR test can be useful in determining how completely the chemotherapy has destroyed the acute leukemia cells, and whether a relapse is likely.

Clinical trials of chemotherapy: Studies are currently in progress to find the most effective combination of chemotherapy drugs while still avoiding unnecessary side effects. New drugs are continually being developed and tested. Studies are underway to determine whether patients with certain unfavorable prognostic features benefit from more intensive chemotherapy. One factor limiting the effectiveness of chemotherapy is that leukemia cells become resistant. Ways to prevent or reverse resistance by using other drugs along with chemotherapy are being studied.

Stem cell transplantation: Studies continue to refine this procedure to increase effectiveness, reduce complications and determine which patients are likely to be helped by this treatment.

Arsenic for Acute Promyelocytic Leukemia: A new drug, arsenic trioxide, has been developed which is also effective in this disease. Studies are now in progress to learn how to combine this with the other treatments to make them more effective.

A new drug for Chronic Myelocytic Leukemia (CML): This drug, which is a pill, appears to be effective for all patients with CML. It is also effective in some patients whose CML has changed into AML. The drug has not been named; and at this time it is called STI571. It is too early to know how long this drug will work, but it has almost no side effects and can be combined with other treatments. Studies of this drug combined with other treatments are planned.

Monoclonal antibodies: These proteins are manufactured in the laboratory and designed to attach to acute leukemia cells. Radioactive chemicals or cell poisons are attached to the antibodies. When the monoclonal antibodies are injected into the person with leukemia, they attach to the leukemia cells and the radioactivity or the cell poison kills the cells. Mylotarg, a monoclonal antibody with a cell poison attached, has recently been approved for use in older adults with acute myelocytic leukemia who might not be able to tolerate the side effects of chemotherapy. But it will still cause very low blood counts because it, like chemotherapy, will kill normal blood-forming cells. Studies are in progress to see how it might best be used.