Discontinuation of TKI therapy and 'functional' cure for CML.

Stopping tyrosine kinase inhibitor (TKI) therapy after achieving a sustained deep molecular response is an emerging treatment goal for patients with chronic myeloid leukaemia in chronic phase (CML-CP). Indeed, the feasibility of stopping TKI therapy has been confirmed in various studies. The Stop Imatinib 1 (STIM1) study has shown a consistent follow-up which allowed defining a new criterion of clinical outcome evaluation, the treatment free remission (TFR). However, announcing a definitive cure remains a challenge owing to the discovery that TKIs spare quiescent leukaemic stem cells (LSC). It is definitely known that even a patient in long-term TFR has persistent LSCs. For this reason, a "functional" cure has been defined and proposed.