Time to best cytogenetic response. A total of 305 (67%) achieved a major cytogenetic response (MCyR), 53 of these responses were achieved after more than 1 year of imatinib treatment (10 of them only after 3 years). A complete cytogenetic response (CCyR) was achieved in 259 patients (57%), 88 of these responses were achieved after more than 1 year of imatinib treatment (28 of them only after 3 years).