New “Natural Cell Killing” Cancer Immunotherapy

A new immunotherapy, called chimeric antigen receptor (CAR) therapy, that uses immune cells cultured from stem cells has been engineered to annihilate cancer cells.

This is set to increase the cancer-killing ability of the immune cells by reconditioning them to extract CAR protein, which has been designed to bond only to cancer cells.

This was led by a team of researchers from the University of California, San Diego and the University of Minnesota.

They stated that this method might lead to “off-the-shelf” stocks of cancer-killing cells.

Researchers described in a paper published in the Cell Stem Cell journal the way the cells displayed strengthened “anti-tumor activity” in mice that had ovarian cancer taken from human cancer cells.

CAR immunotherapy uses white blood cells (T cells) that are genetically modified and grown from cells taken from patients.

Rather than patient-specific T cells, this new method uses NK (natural killer) cells acquired from human induced pluripotent stem cells (iPSCs).

“NK cells offer significant advantages as they don’t have to be matched to a specific patient,” said senior study author Dan S. Kaufman, Professor of Medicine at the University of California, San Diego.

“One batch of iPSC-derived NK cells can be potentially used to treat thousands of patients,” he added.

This opens the possibility of having off-the-shelf, standardized treatments for use with other anticancer drugs.

Although CAR-T cell immunotherapy seems promising, positive trial results don’t always convert to clinical success.
CAR-T cell therapy also presents various obstacles. It is time-consuming and it requires T cells taken from the patient and they only work for that patient.

Professor Kaufman has indicated several cases of “severe toxicity or adverse effects” that have led to organ failure and death, raising serious concerns regarding the safety of CAR-T therapy.

It is unclear how soon CAR-T therapies for solid tumors will become available in the U.S. even though one therapy for a type of acute lymphoblastic leukemia has been approved.