Nilotinib Effective and Safe in Initial Treatment of Chronic Leukemia
Adapted from the NCI Cancer Bulletin.
Preliminary results from a phase III trial testing nilotinib (Tasigna) against imatinib mesylate (Gleevec) as first-line treatment for chronic-phase chronic myelogenous leukemia (CML) indicate that nilotinib is effective and safe as initial treatment for this disease. The findings were presented December 8, 2009, at the American Society of Hematology annual meeting.
Imatinib has been a model for cancer drug developers because it specifically targets a mutant protein called BCR-ABL. Unfortunately, many patients eventually develop resistance to the drug, and this has led to the development of second-generation targeted therapies such as nilotinib and dasatinib (Sprycel) to treat imatinib-resistant CML.
An international group of researchers, led by Giuseppe Saglio, M.D., of the University of Turin in Italy, enrolled 846 patients into the ENESTnd trial. Participants were randomly assigned to receive 300 mg of nilotinib twice daily, 400 mg of nilotinib twice daily, or 400 mg of imatinib once a day.
At 12 months of follow-up, patients receiving either dose of nilotinib had fewer white blood cells expressing the mutant BCR-ABL protein and were more likely to have no leukemia cells detected by laboratory techniques (a complete cytogenetic response) compared with patients receiving imatinib. Patients receiving nilotinib were also less likely to have their disease progress to an advanced stage.
Side effects and rates of drug discontinuation due to side effects were similar between the groups. Nilotinib is known to potentially cause problems with heart rhythm and function, but no severe cardiac side effects have been observed to date in the ENESTnd trial, Dr. Saglio reported. Although the investigators cautioned that the trial is still ongoing, the presenters suggested that nilotinib may eventually replace imatinib as the standard first-line therapy for CML.
Longer-term data from this trial were subsequently published online August 17, 2011, in Lancet Oncology (see the journal abstract).