Surrogate Markers for Treatment-Free Remission in Patients With Chronic Myeloid Leukemia

BCR-ABL1 tyrosine kinase inhibitors (TKIs) improve long-term survival of patients with chronic-phase (CP) chronic myeloid leukemia (CML). Recently, the treatment goal for patients with CML-CP became safe discontinuation of TKIs. Several clinical trials have shown that approximately half of patients who experience a durable deep molecular response during TKI treatment maintain molecular remission after discontinuation of TKIs. However, the factors responsible for successful treatment-free remission (TFR) remain unclear. This study reviews very recent TKI discontinuation studies, focusing on factors responsible for TFR in patients with CML-CP. Longer TKI treatment duration, time of deep molecular response, presence of withdrawal syndrome, deeper molecular response, lower Sokal score, interferon α treatment before TKI administration, and favorable natural killer or T-cell profiles may be associated with TFR. However, different study designs have generated inconsistent data. Further investigations are needed to identify factors that consistently favor achievement of TFR.