Response assessment of patients with chronic myeloid leukemia receiving imatinib mesylate (Glivec) therapy: experience from a single center in a developing country

Imatinib mesylate, a targeted inhibitor of BCR-ABL tyrosine kinase, is a standard of care for chronic myeloid leukemia (CML). There are few publications on responses of patients with CML from the Indian subcontinent. This study analyzed the response rate, progression-free survival (PFS), overall survival (OS), and toxicities in patients with CML given imatinib. Analysis included patients with CML who received imatinib under the GIPAP program at our institution from January 2002 to December 2008. Standard criteria for hematological and cytogenetic responses were used. There were 400 patients, with a median follow-up of 47 months. One hundred and seventy received prior non-imatinib therapy and 230 patients received imatinib upfront. Ninety-five percent of patients achieved complete hematological response. The cumulative best rate of major cytogenetic response was 72%, with 53% complete cytogenetic response and 19% partial cytogenetic response. The estimated PFS and OS at median follow-up for the whole group was 76% and 94%, respectively. Differences in PFS and OS in prior non-imatinib and upfront imatinib groups were not statistically significant. However, better PFS and OS were seen in the upfront imatinib group. Imatinib was well tolerated in our study.