Complete molecular responses are achieved after reduced intensity stem cell transplantation and donor lymphocyte infusion in chronic myeloid leukemia

Patients with newly diagnosed chronic phase chronic myeloid leukemia were treated with imatinib mesylate (IM) for 6 to 12 months to establish disease control, before reduced intensity stem cell transplantation (RISCT). Escalating doses of donor lymphocyte infusions were given from 6 months after transplantation to eradicate residual disease. A total of 18 patients entered the study and 15 received RISCT (median follow-up, 31 months). RISCT was well tolerated with rapid engraftment, short inpatient stays, and few readmissions. Viral reactivation was common, although extensive graft-versus-host disease occurred infrequently. Donor lymphocyte infusions were given as part of the RISCT protocol in 13 of 15 patients. BCR-ABL transcripts continued to decrease after RISCT, and 8 (53%) patients achieved sustained undetectable levels. All patients are currently off IM. Although IM is now established as first-line therapy for chronic phase chronic myeloid leukemia, this protocol is a safe, well-tolerated, and effective strategy in these patients. This study is registered at http://www.controlled-trials.com as ISRCTN86187144.