Surrogate markers for treatment-free remission in patients with chronic myeloid leukemia

Abstract BCR-ABL1 tyrosine kinase inhibitors improve long-term survival of patients with chronic phase chronic myeloid leukemia (CML-CP). Recently, the treatment goal for patients with CML-CP became safe discontinuation of tyrosine kinase inhibitors (TKIs). Several clinical trials show that approximately half of patients who achieve a durable deep molecular response (DMR) during TKI treatment maintain molecular remission after discontinuation of TKIs. However, the factors responsible for successful achievement of 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 DMR, presence of withdrawal syndrome, a deeper molecular response, a lower Sokal score, interferon α treatment prior to TKI administration, and favorable NK- 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.