Two treatment approaches using donor or engineered natural killer (NK) cells led to remission in people with blood cancers, recent research shows. NK cells act as sentinels to hunt down malignant cells. Unlike T cells, which are most commonly used for immunotherapy, NK cells don’t have to be customized for each patient, and they are less likely to cause side effects.

As reported at the American Association for Cancer Research Annual Meeting, combining NK cells from umbilical cord blood with a bispecific antibody led to remission in 89% of patients with advanced Hodgkin lymphoma. “We were favorably surprised by the quality of tumor responses in patients,” says Yago Nieto, MD, PhD, of the University of Texas MD Anderson Cancer Center.

In addition, the biopharmaceutical company Nkarta recently announced positive results from a pair of small trials evaluating off-the-shelf CAR-NK cells genetically reprogrammed to target cancer. In the first study, three out of five people with advanced acute myeloid leukemia who received high doses of a product dubbed NKX101 achieved a complete response. In the second study, five out of six non-Hodgkin lymphoma patients treated with a high dose of another NK cell product, NKX019, experienced remission. In both studies, the treatment was safe and well tolerated, and patients did not experience the severe adverse events sometimes seen with CAR-T therapy.