Key clinical point: Leukemic stem cells (LSCs) persisted in bone marrow (BM) but not in peripheral blood (PB) of patients with chronic-phase chronic myeloid leukemia (CML-CP) with deep molecular response (DMR) . Investigating BM LSCs before deciding tyrosine kinase inhibitor (TKI) discontinuation could help achieve and maintain stable treatment-free remission (TFR).
Major finding: LSCs persisted in BM of patients in DMR (281.1 LSC/10 6 white blood cells [WBCs]) but not in PB. BM LSCs were observed in newly diagnosed patients (805 LSCs/10 6 WBC) and TKI-treated patients with BCR-ABL-positive hematopoiesis (143.5 LSCs/10 6 WBC). PB LSCs were highest in newly diagnosed patients (237.5 LSCs/μL) but reduced in TKI-treated patients with BCR-ABL-positive hematopoiesis (13.5 LSCs/μL).
Study details : This study included 38 patients with CML-CP who were either recently diagnosed (n=7), had BCR-ABL-positive hematopoiesis under TKI therapy (n=19), or achieved DMR with TKIs (n=12).
Disclosures: This study was funded by Pfizer through Pfizer Independent Medical Grants program. The authors declared no conflicts of interest.
Source: Ilhan O et al. Int J Lab Haematol. 2021 Apr 9. doi: 10.1111/ijlh.13528 .