<qa>  What is the randomized study comparing interferon administered for fix duration after TKI wasSo 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. 