Treatment free remission in chronic myeloid leukemia: Lights and shadows.

In addition to the best possible overall survival, discontinuation of the tyrosine kinase-inhibitor (TKI) treatment [treatment free remission (TFR)] without observing a recurrence of the disease has become a standard part of chronic myeloid leukemia (CML) care. Worldwide, more than 2000 patients with CML have attempted TFR, and very rare instances of disease transformation have been reported. Several studies in the last decade have demonstrated the feasibility and safety of TKI discontinuation in selected patients with CML who achieve deep and sustained molecular response with TKI. This has moved prime-time into clinical practice although open questions remain in terms of understanding the disease biology that leads to successful TKI cessation in some patients while not in others. Despite the remaining questions regarding which factors may be considered predictive for TFR, treatment interruption is a safe option provided that adequate molecular monitoring is available, with prompt re-initiation of TKIs as soon as major molecular response has been lost. Data from ongoing trials should help refine decisions as to which patients are the best candidates to attempt TKI discontinuation, frequency of a safe monitoring, optimal strategies to sustain ongoing TFR and increase the number of patients who can access to discontinuation programs.