Table 3.

Selected results of clinical studies on NK cell-based immunotherapy

	Study	NK cell infusion regimen	Results
In non-transplant setting
In advanced AML	Miller, 2014	Haplo-NK, activated with IL-2, Flu/Cy	Five of 19 (26%) patients achieved CR
	Bachanova, 2014	Haplo-NK, depletion of Tregs, activation of IL-2, Flu/Cy	Eight of 15 patients (53%) achieved remission at day 28, CR (n = 3), (CRp; n = 2), and CRi (n = 3)
	Cooley, 2019	Haplo-NK cells given with rhIL-15, Flu/Cy	Fourteen of 40 patients (35%) achieved CR/CRi
In MRD positive AML	Zhao, 2020	IL-21/4-1BBL-expanded NK cellchemotherapy with Flu/Cy or anthracyclines/Cy	Effective rates were 50% or 60% in Flu/Cy (n = 10) or anthracyclines/Cy (n = 10); DFS was clearly better in the NK group than in the historical group
As consolidation or maintenance	Jiang, 2019	IL-21/4-1BBL-expanded NK cell infusion during 4 to 7 courses of chemotherapy	The 3-year LFS was better in the NK group than in the control group (65.1% vs. 43.5%, P = 0.047)
	Nguyen, 2019	Haplo-NK, activated with IL-2, Flu/Cy	NK cells did not improve EFS (60.7% vs. 69.1%; P = 0.553) over chemotherapy alone
In transplant setting
Post-HSCT	Choi, 2014	Donor-derived, IL-15 plus IL-21-stimulated CD3-depleted NK cells on days 14 and 21 post HSCT	Post-transplantation NK cells significantly decreased leukemia progression (74% to 46%, P = 0.038)
	Choi, 2016	Additional donor NK-cell infusions given on days 6 and 9 in addition to 14 and 21 post HSCT	Compared with the above study findings, an additional NK infusion on days 6 and 9 was not associated with less leukemia progression
Pre-HSCT	Lee, 2016	IL-2 activated NK cell infusion after conditioning chemotherapy and before stem cell infusion	Durable CR occurred in 5 of 21 patients
	Ciurea, 2017	mbIL21 ex vivo expanded donor-derived NK cells on days −2, +7, and +28	The incidence was significantly lower in the NK group than in the control group for CMV reactivation (30.8%) (70.4%, P = 0.01)

CRp, CR without platelet recovery; CRi, CR with incomplete recovery.