Landmark analysis of overall survival according to the cytogenetic response at 12 months. A total of 421 patients who were on study treatment at 12 months were categorized according to their degree of cytogenetic response by 12 months. The estimated 6-year OS rate was 92% in patients with CCyR, 89% for PCyR, 79% for minor CyR, and 60% for minimal CyR as well as for patients who had not achieved any cytogenetic response on the first 12 months of imatinib treatment.