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At the 2016 meeting of the American Association for the Advancement of Science, immunotherapy researcher and oncologist Stanley Riddell of Seattle's Fred Hutchinson Cancer Research Center, announced an exciting new cancer treatment. "The early data are unprecedented," Dr. Ridell said. Adoptlive cell therapy could be the long-awaited breakthrough in the war of cancer.
What Is Adoptive Cell Therapy?
For about 100 years cancer specialists have been using radiation and chemotherapy to attack cancer cells directly. The problem with this approach has always been that any treatment that kills cancer cells also kills healthy cells. In recent decades, oncologists have been developing a different approach, recruiting the body's own immune defenses into the fight against cancer. Of course, any non-medical observer might ask why, if our immune systems can fight cancer, do we need treatment at all?
The reason our immune systems don't always defeat cancer (actually, they do more often than not, before cancer is ever symptomatic) is that some cancer cells have an ability to evade detection. They grow inside tumors that aren't connected with most of the body's blood vessels. White blood cells don't detect the cancer because they never come in contact with it. Or the white blood cells known as T cells simply don't have a targeting system for cancer. They don't have a way of attacking cancer without also attacking healthy cells.
It uses the patient's existing T cells. In an earlier version of this technique, the T cells are removed from the patient, grown in the lab, and given back to the patient in vastly increased numbers. As many as 100 billion T cells may be grown in the lab and infused back into the patient's bloodstream. Sometimes this is enough to defeat a cancer.
In a more advanced version of this technique called adoptive cell therapy, a second set of laboratory techniques creates a "chimera" of the patient's native T cells with an antibody attached to what is called a chimeric antigen receptor of CAR, and then multiplies the result. Adding an antibody to the T cells turns them into what some researchers call an elite fighting force for the kind of cancer on which the antibody acts. This method hasn't been used with very many people, but in some studies, 90 percent of leukemia patients have had "complete responses," meaning they have gone into remission, with adoptive cell therapy.
This therapy is not yet FDA-approved, but it is being adapted to modifying other kinds of immune cells, such as natural killer (NK) cells, and to other kinds of cancer, such as non-small cell lung cancer, melanoma, certain kinds of of bone cancer, and multiple myeloma. Adoptive cell therapy boosts the immune system's first line of defense against cancer and gets results, unfortunately, not all of them are positive.
Downside to Adoptive Cell Therapy
Adoptive cell therapy, in one study, eliminated 94 percent of participants with acute lymphoblastic leukemia. This would seem to be a wonderful advance. Most of the time, it is, however, in that other 6 percent there were patients who had to be put in ICU and later died from side effects of the immunotherapy.