Seven-year follow-up of patients receiving imatinib for the treatment of newly diagnosed chronic myelogenous leukemia by the TARGET system

Abstract

The TARGET system is an online database that can be easily accessed by physicians. The registration of one's own chronic myeloid leukemia (CML) patients in the TARGET system makes it possible to share experiences among physicians, and, thus, may facilitate appropriate treatment for patients. Patients were registered in the TARGET system from October 2003 to March 2010 in Japan. A total of 1236 patients from 176 hospitals were registered in Japan. We analyzed data from 639 CML chronic phase patients not receiving prior therapy registered in this system. After 90 months follow-up, high survival rates were demonstrated for imatinib-treated newly diagnosed CML patients, with event-free survival (EFS), progression-free survival (PFS), and overall survival (OS) rates of 79.1, 94.8, and 95.1%, respectively. A landmark analysis of 296 patients who showed a complete cytogenetic response (CCyR) at 12 months after the initiation of imatinib treatment revealed that, at 90 months, 99% of patients (95% CI, 98-100) had not progressed to accelerated phase (AP) or blastic crisis (BC). The patients showing a CCyR and a reduction of at least 3log levels of BCR-ABL transcripts after 18 months of treatment had an estimated survival rate without CML progression of 100% at 84 months. The probability of achieving undetectable BCR-ABL in patients by 72 months with an major molecular response (MMR) at 12 months was 86.5%, compared with 64.7% for those without an MMR (p < 0.0001). There were no new safety issues. In summary, based on this 7-year TARGET analysis, imatinib showed a continual clinical benefit as first-line therapy for newly diagnosed CML. The TARGET system may represent a more practical and general feature compared with the IRIS study.