Durable complete molecular remission of chronic myeloid leukemia following dasatinib cessation, despite adverse disease features.

Patients with chronic myeloid leukemia, treated with imatinib, who have a durable complete molecular response, might remain in complete molecular response after stopping treatment. Previous reports of patients stopping treatment in complete molecular response have included only patients with a good response to imatinib. We describe 3 patients with stable complete molecular response on dasatinib treatment following imatinib failure. Two of the 3 patients remain in complete molecular response more than 12 months after stopping dasatinib. In these 2 patients we used highly sensitive patient-specific BCR-ABL1 DNA PCR to show that the leukemic clone remains detectable, as we have previously shown in imatinib-treated patients. Dasatinib-associated immunological phenomena, such as the emergence of clonal T-cell populations, were observed both in one patient who relapsed and in one patient in remission. Our results suggest that the characteristics of complete molecular response on dasatinib treatment may be similar to that achieved with imatinib, at least in patients with adverse disease features.