National / Science & Health

Japanese team plans to use iPS cells in clinical trial for cancer patients


A Japanese team is preparing a clinical trial to inject immune cells made from induced pluripotent stem (iPS) cells into patients with head and neck cancer, it has been learned.

The team of Riken and Chiba University researchers will file for state approval of the trial as early as autumn and start as soon as approval is given, informed sources said Thursday. The trial would become the first in Japan to use iPS cells as a possible cancer treatment.

Key members of the team include Haruhiko Koseki, executive of the Riken Center for Integrative Medical Sciences, and Chiba University professor Yoshitaka Okamoto.

The trial is expected to be conducted on three patients with recurrent cancers that cannot be sufficiently treated through surgery.

The team plans to collect from the blood of healthy people a type of white blood cell known as a natural killer T cell, which attack cancer cells and activate other immune cells. The cells will then be converted into iPS cells, which will be developed again into natural killer T cells.

The new natural killer T cells will be transplanted into the patients through a series of three intravascular injections. In the first round, about 30 million natural killer T cells will be transplanted. The team will examine the positive and negative effects of the treatment and adjust the number of cells for the second and third transplants.

In a Chiba University clinical study using a patient’s own natural killer T cells, a similar transplant helped reduce cancer cells.

Blood contains only a small number of the cells and it takes time to culture them, while the number of iPS cells can be increased easily, making it easier to produce a large number of natural killer T cells, the sources said.

IPS cells may turn cancerous if they stay within subjects without being converted into the cells researchers intend to produce. But this is unlikely to be a problem in the planned trial, because it will use cells from other subjects. The cells are expected to be cleared away by the patient’s immune systems even if they turn cancerous.