Lower than expected cytogenetic and molecular response to imatinib in Mexican patients with chronic myelogenous leukemia.

Imatinib has been considered as the gold standard for drug therapy of chronic myelogenous leukemia (CML) because it offers higher cytogenetic response and better quality of life than traditional drugs. In this study we applied the standard 400 mg dose of imatinib in 37 CML Ph (+) Mexican patients, monitoring their cytogenetic response using fluorescent in situ hybridization and carrying out molecular analyses using reverse transcription polymerase chain reaction. The study included 19 male and 18 female patients with a median age of 41 years. The median follow-up time from diagnosis was 56 months. Thirty-six patients (97%) achieved complete hematologic response in a median time of 29 days. Complete cytogenetic response and complete molecular remission was observed in only five (13%) and three (8.1%) patients, respectively, less than the expected rate (50-90%) reported in other studies.