Survival Rate for High-Risk Childhood Leukemia Doubled by New Treatment

A new study has shown that adding continuous daily doses of imatinib mesylate to regular chemotherapy more than doubled three-year survival rates for children with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL).

Researchers participating in the Children's Oncology Group (Providence, RI, USA) conducted a study at nearly 20 North American centers that involved 92 children and adolescents between 1 and 21 years of age with Ph+ ALL. Each received an initial four weeks of standard chemotherapy. They were assigned to five different groups that received imatinib for different lengths of time: 42, 63, 84, 126, or 280 days. All patients received an additional 336 days of imatinib.

The results showed that the group that received imatinib for more than 280 continuous days had survival rates of 87%, a dramatic improvement over traditional chemotherapy and blood and marrow transplantation. Groups that received imatinib for 84 and 126 days showed moderate improvement in survival rates, while groups receiving the drug for 42 and 63 days had the same survival rates as current standard treatments. There were also 21 patients with Ph+ ALL who were treated with blood and marrow transplantation followed by six months of imatinib; this approach did not affect survival rates. The study was published n the October 5, 2009, issue of the Journal of Clinical Oncology.

"Using imatinib plus chemotherapy had a synergistic type of interaction; I never expected these results,” said lead author Kirk Schultz, M.D., a pediatric oncologist and head of childhood cancer research at the Child & Family Research Institute (CFRI; Vancouver, Canada). "Although it's very promising, we need to do more follow up to get the five-year survival data and determine the long-term survival. We submitted our study for publication earlier instead of waiting because the data was so exciting and this type of leukemia is such high risk.”

Imatinib mesylate, known commercially as Gleevec, is the first member of a new class of agents that act by inhibiting particular tyrosine kinase enzymes, instead of nonspecifically inhibiting rapidly dividing cells. It is used to treat some adult leukemias and gastrointestinal cancers, and binds to a specific protein in cancer cells and prevents the cells from proliferating.

Related Links:
Children's Oncology Group
Child & Family Research Institute