HOUSTON -- Two drugs approved for treatment of drug-resistant chronic myeloid leukemia provide patients with quicker, better responses as a first therapy than the existing front-line medication, according to two studies published online by the New England Journal of Medicine.
Separate international phase III clinical trials compared high-quality remissions after one year of treatment between the standard-of-care drug imatinib, also known as Gleevec, and the second-line drugs nilotinib (Tasigna) and dasatinib (Sprycel). In both trials, previously untreated CML patients who took the newer drugs reached complete cytogenetic response and major molecular response two important measures of remission -- faster than those taking imatinib. They were also less likely to have their disease progress to advanced stages.
"The second-generation CML drugs are more effective than imatinib and less toxic overall," said Hagop Kantarjian, M.D., professor and chair of The University of Texas MD Anderson Cancer Center's Department of Leukemia. Kantarjian is the corresponding author of the dasatinib study and co-author of the nilotinib study.
Drugs likely to increase survival
"We've learned in cancer therapy that it's important to use your big guns up front," Kantarjian said. "We know that achieving complete cytogenetic response or major molecular response within a year of starting treatment is associated with more favorable long-term survival. Using these second-generation drugs first will likely improve outcomes for patients with chronic myeloid leukemia."
Imatinib, a targeted therapy that blocks the activity of a fusion protein called BCR-ABL that is created by the aberrant Philadelphia chromosome, was a breakthrough drug for CML, nearly doubling the median five-year survival rate for the disease from 50 to 90 percent.
However, 30-40 percent of imatinib patients don't reach a complete cytogenetic or major
|Contact: Scott Merville|
University of Texas M. D. Anderson Cancer Center