 So far, there is no randomized study comparing interferon administered for fix duration after TKI was stopped versus observation to see whether the percentage and duration of CML patient who remains TKI-free can be increased and prolonged with interferon, respectively. It will be of interest to see how long the group which was given interferon remains TKI-free. If they remain TKI-free for a long duration, it not only suggests the interferon-induced immunity, but also suggests the interferon-induced immunity can be induced when only a very low level of leukemic cells present. Economical wise, TKI-free certainly give a big relief on the limited health budget of the on-growing CML population. 