"This novel anti-leukemia drug that we have been working on shows considerable promise for going into the clinic," said Dr. Robert Ilaria Jr., associate professor of internal medicine and molecular biology and senior author of the study that will appear in an upcoming issue of Blood. The study is available online.

The study on the drug, called PD166326, was done in mice with a form of leukemia similar to human chronic myelogenous leukemia (CML), which is diagnosed in about 5,000 people in the United States each year. Patients with CML produce a mutated enzyme that stimulates white blood cells to overproduce, causing leukemia.

The Blood study shows that PD166326 is nearly 100 times more potent than the current drug imatinib (Gleevec) against cells expressing this enzyme, Dr. Ilaria said.

"Our study represents the first published characterization of this novel anti-leukemia drug in animals," Dr. Ilaria said. Gleevec is approved by the Food and Drug Administration for the treatment of patients with CML. The drug blocks signals within cancer cells and prevents a series of chemical reactions that cause the cells to grow and divide.

Although Gleevec has been highly successful against CML, it is unknown whether the drug can permanently eradicate all leukemia cells with the specific aberrant enzyme found in CML patients. About 15 percent to 20 percent of patients who take Gleevec become resistant to the drug and relapse, leaving few effective treatment options.

In the Blood study, Dr. Ilaria and his colleagues introduced the cancer-causing enzyme into mouse bone-marrow cells to generate mice with a form of leukemia similar to human CML. The disease usually develops slowly, although it can progress to an accelerated phase.

When mice received a single oral dose
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Contact: Scott Maier
scott.maier@utsouthwestern.edu
214-648-3404
UT Southwestern Medical Center
2-May-2005