- Patients must have a complete cytogenetic response (CCyR) on a TKI (imatinib or nilotinib) for a minimum of 1 year leading up to enrollment. Complete cytogenetic response is defined as 0% Ph+ cells in metaphase, in the bone marrow and/or a negative peripheral blood FISH analysis for the Bcr-Abl gene fusion, and an ongoing CCyR must be confirmed by bone marrow aspirate cytogenetics and/or peripheral blood FISH for Bcr-Abl within 4 weeks of starting treatment.