Hematopoietic cell transplantation for myeloid/NK cell precursor acute leukemia in second remission

Effectiveness of venetoclax and azacytidine against myeloid/natural killer cell precursor acute leukemia

Myeloid/natural killer (NK) cell precursor acute leukemia (MNKPL) is a rare leukemia subtype that possibly originates from precursor NK cells. The disease has a poor prognosis, and information on its treatment is lacking. We herein report the first case of a 46-year-old woman with MNKPL who was refractory to two lines of acute myeloid leukemia (AML)-type intensive chemotherapy but was successfully treated with venetoclax and azacytidine (VEN/AZA). She was diagnosed with MNKPL based on the conformations of immature lymphoblastoid morphology without myeloperoxidase reactivity that showed a CD7/CD33/CD34/CD56/HLA-DR positive phenotype and extramedullary regions. The disease was refractory to induction therapy with daunorubicin and cytarabine (DNR/Ara-C) and to reinduction therapy with mitoxantrone, etoposide, and cytarabine (MEC). After two lines of induction chemotherapy, massive pericardial and pleural effusion was found, and was suspected to be extramedullary lesions. The patient developed cardiac tamponade and required pericardiocentesis. Thus, VEN/AZA was administered as third-line therapy. After two cycles of VEN/AZA, the pericardial and pleural effusion disappeared, and complete remission was achieved. The patient received post-transplant cyclophosphamide-based haploidentical transplantation and has stayed relapse-free as of her last follow-up examination 2 years after diagnosis.

Myeloid/natural killer (NK) cell precursor acute leukemia as a distinct leukemia type

Myeloid/natural killer (NK) cell precursor acute leukemia (MNKPL) has been described on the basis of its unique immunophenotype and clinical phenotype. However, there is no consensus on the characteristics for identifying this disease type because of its rarity and lack of defined distinctive molecular characteristics. In this study, multiomics analysis revealed that MNKPL is distinct from acute myeloid leukemia, T cell acute lymphoblastic leukemia, and mixed-phenotype acute leukemia (MPAL), and NOTCH1 and RUNX3 activation and BCL11B down-regulation are hallmarks of MNKPL. Although NK cells have been classically considered to be lymphoid lineage-derived, the results of our single-cell analysis using MNKPL cells suggest that NK cells and myeloid cells share common progenitor cells. Treatment outcomes for MNKPL are unsatisfactory, even when hematopoietic cell transplantation is performed. Multiomics analysis and in vitro drug sensitivity assays revealed increased sensitivity to l-asparaginase and reduced levels of asparagine synthetase (ASNS), supporting the clinically observed effectiveness of l-asparaginase.