New gene treatment effective for some leukemia patients

A new way of genetically altering a patient’s cells to fight cancer has helped desperately ill people with leukemia when every other treatment had failed, researchers reported Monday in the journal Nature Medicine.

The new approach, still experimental, could eventually be given by itself or, more likely, be used in combination treatments — analogous to antiviral “cocktails” for HIV or multi-drug regimens of chemotherapy for cancer — to increase the odds of shutting down the disease.

Researchers say the treatment may be more promising as part of a combination than when given alone because, although some patients in the small study have had longlasting remissions, many others had relapses.

The research, conducted at the National Cancer Institute, is the latest advance in the fast-growing field of immunotherapy, which fires up the immune system to attack cancer. The new findings build on two similar treatments that were approved by the Food and Drug Administration this year: Kymriah, made by Novartis for leukemia; and Yescarta, by Kite Pharma for lymphoma.

In some cases, those two treatments have brought long and seemingly miraculous remissions to people who were expected to die.

Kymriah and Yescarta require removing millions of each patient’s T-cells — disease-fighting white blood cells — and genetically engineering them to seek and destroy cancer cells. The T-cells are then dripped back into the patient, where they home in on protein molecules called CD19 found on malignant cells in most types of leukemia and lymphoma.

The new treatment differs in a major way: The T-cells are programmed to attack a different target on malignant cells, CD22.

Researchers have been eager to test this type of T-cell. One reason is that they hoped to find that CD19 was not the only vulnerable target, “not some kind of unicorn,” said Dr. Crystal L. Mackall, the senior author of the study and the associate director of the Stanford University School of Medicine’s cancer institute. Cancer cells are highly adaptable and often find ways to evade treatments aimed at only one target.

“The idea that we could have one magic bullet is naive,” she said.