We evaluated the safety and efficacy of allogeneic, ex-vivo expanded, NK cells, MG4101, in patients with refractory or relapsed AML. The relationship between immunological characteristics and clinical responses was analyzed. Between April 2018 and February 2020, 11 patients (male:female = 5:6) were treated with MG4101. Of eight evaluable patients, two (25.0%) showed partial response and two (25.0%) showed stable disease. The median overall survival was 3.4 months (95% confidence interval [95% CI], 2.5-4.3 months), and the allogeneic hematopoietic stem cell transplantation (HSCT) censored duration of response was 2.9 months (95% CI, 1.5-4.4 months). Two patients underwent HSCT after MG4101 treatment. Except for one grade 3 infusion-related reaction, no serious adverse events were observed. The sum of activating KIRs in responders tended to be higher than that in non-responders. Analyses of NKRL and KIR highlighted the importance of immunological mechanisms in treating myeloid neoplasms.
Keywords: MG4101; acute myeloid leukemia; allogeneic NK cell therapy.