More Evidence That Genetically Engineered Cells Can Annihilate Cancer

Long touted as a potential breakthrough in cancer treatment, gene therapy took one step closer to FDA approval this week with the announcement of promising results that use a technique called CAR-T cell therapy. The treatment involves filtering a patient's blood, removing the special cells that power the immune system, and genetically altering them to attack cancer in the body. According to Kite Pharma, the pharmaceutical company that developed the treatment, more than a third of patients with aggressive lymphoma showed no sign of disease six months after receiving a single treatment. If those results hold up to scrutiny, CAR-T could become the first FDA-approved gene therapy.

A major challenge in treating cancer is that the body doesn't typically recognize cancer as a threat, and the immune system doesn't attack it. CAR-T is a type of immunotherapy, which uses different techniques to jumpstart the immune system into recognizing and attacking cancer cells.

In the case of CAR-T, the "CAR" stands for "chimeric antigen receptors"—genetically engineered to bond specifically with a patient's cancer. (Think of it as a customized, artisanal antigen.) They're grafted onto T-cells, the front-line soldiers of the body's immune system. The altered cells are then returned to the patients intravenously, where they divide and spread, creating an artificially induced immune response.

The study focused on 101 patients with multiple types of aggressive Non-Hodgkin's lymphoma, a blood cancer. Six months after a single treatment, 41 percent had seen their cancer shrink at least by half and 36 percent were in complete remission, with no sign of the disease. One patient told the Associated Press that he watched his tumors "shrink like ice cubes." In total, 82 percent of patients saw their cancers shrink by at least half at some point in the study.

The approach carries with it some dangers, though; three patients in the study died of causes unrelated to the advancement of their cancers, and two of those deaths were attributed to the treatment. One side effect was the immune system dangerously overreacting in attacking the cancer; researchers saw that happen in 13 percent of the study patients—but say they're getting better at treating such a reaction.

Competition is fierce among companies vying to bring the treatment to market. Kite Pharma now has a lead over Novartis in the race to win FDA approval; a third company, Juno Therapeutics, just announced that it would shelve one version of its CAR-T treatment after five patient deaths caused by swelling and fluid in the brain. (It will continue researching a second approach to CAR-T.) Kite, which hasn't disclosed anything about what kind of price would be put on this new treatment, plans to submit a plan to the FDA by the end of March, bringing gene therapy that much closer to potential approval.