Imatinib (Gleevec), which is also licensed for the treatment of CML, and IFN-α are the two most active forms of non-transplant therapy and have been shown, in vitro, to have additive or synergistic antiproliferative effects using cells positive for the above-mentioned chromosomal abnormality (BCR-ABL) and in colony-forming assays using samples from CML-positive patients. This evidence concerns the gene BCR and chronic myelogenous leukemia, BCR-ABL1 positive.