A trial looking at natural killer cells after chemotherapy and radiotherapy for acute myeloid leukaemia

This trial was done to find out if having injections of natural killer (NK) cells from a healthy relative helps people with acute myeloid leukaemia (AML). And if it is a safe treatment.

Doctors usually treat AML with chemotherapy. After chemotherapy, there will be a lot of natural killer (NK) cells in your blood. We all have these cells in our blood, but there are more of them after chemotherapy. The NK cells are part of the immune system. They can target and attack any leukaemia cells that are left after chemotherapy. We know from earlier research that NK cells help people stay in remission but some leukaemias are resistant to them.

Doctors want to find ways of safely increasing the number of NK cells and make them better at killing resistant leukaemias. In this trial, they looked at using NK cells from a healthy relative. This is called an allogeneic donor cell infusion.

But some cells in the infusion called T lymphocytes could see your normal body cells as foreign and attack them. This is called graft versus host disease (GVHD). The researchers reduced the risk of GVHD by removing almost all the T lymphocytes. And they looked at a way of changing the NK cells so that they can kill resistant leukaemia cells, but don’t kill normal blood or bone marrow cells. These are called tumour activated NK cells (TaNKs).

The aim of the trial was to make sure that this type of treatment is safe, and to see

• Whether the donor TaNKs stay in the immune system

• If they can help to lower the risk of leukaemia coming back