Gleevec Has Lower Efficacy from Population Based Studies Compared to Clinical Trials
UK doctors claim that population based studies of Gleevec efficacy in chronic myelogenous leukemia
patients may show less efficacy than from clinical trials.
The IRIS trials showed that on 400mg Gleevec, the overall survival at 5 years is 89%. The trial results
indicated that the rate of disease progression falls with time. Doctors wished to establish Gleevec efficacy in the
general population to have some indication of reproducibility.
In the north-west of England, 12 hospitals took part in the population-based study with CML patients aged
over 16 years who reported to the hospitals between 2003 and 2006 included in the study. Patients who took
Gleevec monotherapy first-line were assessed.
Over the 42 months of study, there were 1.2 cases per 100,000 population per year which is similar
incidence from other studies. The median age at diagnosis was 53.4 years, also similar to other studies.
The overall complete cytogenetic response rates were 41% at 12 months, 49% at 18 months and 51% at 24
months. MMR rates were 31% at 24 months. At 24 months, 49% of patients either relapsed, did not achieve
CCR or were intolerant. Therefore, the first-line Imatinib failure rate was 49% from this study.
Clinical trial studies on 400mg first-line Imatinib from the IRIS trials, from MD Anderson Cancer Center and
from Hammersmith Hospital have shown an 87% CCR rate and 90% progression-free survival. The cumulative
incidence of the loss of CCR from the Hammersmith study was 17% at 48 months. None of these studies were
population based.
The data by the UK doctors in the present article show that caution should be used to extrapolate clinical
trial data to population-based studies.
Reference: ‘A Population Study of Imatinib in Chronic Myeloid Leukemia Demonstrates Lower Efficacy Than In
Clinical Trials’- Clark, R. E. et al. Leukemia, 28 August, 2008.