Imatinib May Be Safer Than Dasatinib for Chronic Myeloid Leukaemia: Presented at EHA
By Jill Stein
VIENNA, AUSTRIA -- June 8, 2007 -- Patients with chronic myeloid leukaemia (CML) in the chronic phase who are treated with high-dose imatinib may have lower adverse event rates and an improved adverse event profile than patients treated with dasatinib, according to data released here at the 12th Congress of the European Hematology Association (EHA).
Erick Moyneur, MA, senior economist, Analysis Group, Inc., Boston, Massachusetts, United States, and colleagues used data from pivotal clinical trials to compare the treatment-emergent adverse event profile of high-dose imatinib at a dose greater than 400 mg and dasatinib in patients with chronic-phase CML who had previously been treated with standard-dose imatinib (400 mg daily).
Data on adverse events were extracted for patients in whom the daily imatinib dose was escalated at least twice daily from 400 mg to 600 or 800 mg during the International Randomised Study of Interferon and ST1571. All subjects in the trial were adults with newly diagnosed, previously untreated, chronic-phase CML.
Adverse events data on dasatinib were extracted from the Food and Drug Administration's Sprycel Drug Approval Package for patients receiving dasatinib 70 mg twice daily for imatinib-resistant or intolerant chronic-phase CML.
In his analysis, Moyneur included about 150 patients treated with high-dose imatinib and 200 treated with dasatinib.
All adverse events were considered for imatinib, whereas only those deemed by the investigator to be drug-related were included for dasatinib.
The median daily dose during observation was 667.1 mg in the high-dose imatinib group and 114 mg in the dasatinib group.
Results showed that adverse events were significantly more common in the dasatinib than in the high-dose imatinib group (P <.05). These adverse events included anaemia, neutropenia, thrombocytopenia, gastrointestinal bleeding, oedema, pleural effusion, central nervous system haemorrhage, congestive heart failure, diarrhoea, nausea, vomiting, and rash.
These results demonstrate that adverse events may be less likely with high-dose imatinib than dasatinib in patients with chronic-phase CML, Moyneur said in his presentation on June 8th.
He emphasised, however, that the study has some important limitations. For example, the imatinib and dasatinib groups were drawn from different trials.
Also, patients with newly diagnosed, chronic-phase CML who received imatinib were compared with imatinib-resistant or intolerant chronic-phase CML patients who received dasatinib as a second-line therapy. Since the dasatinib population had more severe CML, the dasatinib group may have had a higher susceptibility for adverse events, he added.
Finally, he said that the study was not conducted in a randomised setting.
