Targeted therapy for childhood leukemia

In recent years, new drugs that target specific parts of cancer cells have been developed. These targeted drugs work differently from standard chemotherapy drugs. They often have different (and less severe) side effects. Some of these drugs may be useful in certain cases of childhood leukemia.

For instance, drugs such as imatinib (Gleevec) and dasatinib (Sprycel) specifically attack cells that have the Philadelphia chromosome (a shortened chromosome 22 that results from a translocation with chromosome 9).

Nearly all children with chronic myeloid leukemia (CML) have this abnormal chromosome in their leukemia cells. These drugs are very effective at keeping the leukemia under control for long periods of time in most of these children, although it's not yet clear if the drugs can help cure CML.

A small portion of children with acute lymphocytic leukemia (ALL) also have leukemia cells with the Philadelphia chromosome. Studies are now being done to find out if these drugs can be combined with chemotherapy to get better outcomes. Early results from such studies have been promising.

These drugs are taken daily as pills. Possible side effects include diarrhea, nausea, muscle pain, fatigue, and skin rashes. These are generally mild. A common side effect is swelling around the eyes or in the hands or feet. Some studies suggest this fluid buildup may be caused by the drugs' effects on the heart. Other possible side effects include lower red blood cell and platelet counts at the start of treatment. These drugs may also slow a child's growth, especially if used before puberty.