The gene, first identified in 1992, has been shown to be a primary cause of aggressive, treatment-resistant acute myeloid leukemia. Approximately 40 percent of patients with acute myeloid leukemia have FLT3 mutations, and most of them will not be cured using current therapies, according to the research team.

Clinical trials to test the safety and effectiveness of the drug in adult patients who have relapsed or stopped responding to standard therapy and who have the mutations are now underway.

"Right now, acute myeloid leukemia patients with FLT3 mutations have a dismal diagnosis with little hope of cure. We hope to change that with this new drug," says Donald Small, M.D., Ph.D., study director. "Since it selectively targets the genetic error, CEP-701 turns it from a negative indicator to a positive one. This is what molecular medicine is all about, finding the cellular mistakes that work against us to cause cancer and turning them to our advantage to kill the cells."

The investigators tested CEP-701 in mouse cell lines and human leukemia cells with FLT3 mutations and found the drug interfered with the signal of the altered gene --- leading to death of the leukemic cells.

CEP-701 is one of a new class of drugs called tyrosine kinase inhibitors, named because of their ability to block specific cell signaling proteins. "Mutant FLT3 uses its tyrosine kinase portion to signal leukemia cells to grow and also to prevent them from dying," explains Mark Levis, M.D., Ph.D., lead author. "By inhibiting the gene's ability to communicate with cells, we can slow the growth and promote the death of [acute myeloid leukemia] cells. In essence, we render the gene powerless. It's as if it never existed," he says.

Acute myeloid leukemia is diagnosed in more than 10,000 adults and children each year in the U.S. It is the most common form of adult leukemia and the second most common type of childhood leukemia.