Why immunotherapy could be the cure to cancer we have all been waiting for

Cancer research leader Carl June on how targeting immune cells could provide potentially lifelong protection

Cancer cells spread due to their insidious ability to bypass the body’s immune system. To fight them, oncologists have historically turned to toxic drugs that kill a cancer’s dividing cells. But over the past decade, researchers have been figuring out how to trick the immune system into attacking tumors. In late 2015, the FDA approved Amgen’s IMLYGIC, a genetically engineered virus that might trigger the immune system to kill cancer. For now, the drug is only for melanoma, but it’s a harbinger of a major shift in the fight against cancer. University of Pennsylvania’s Carl June, a leader in immunotherapy research, explains how IMLYGIC, and other drugs like it, could change how cancer is treated.

Popular Science: How does immunotherapy differ from chemo and radiation?

Carl June: A reprogrammed immune system could have a lifelong antitumor effect. That sets it apart from short-term therapies, where you get the effect only until the drugs metabolize. Plus, the lessons we learn from the immunotherapy for one cancer will apply to other cancers.

PS: The treatment you developed, CAR (chimeric antigen receptors) T cell therapy, uses engineered T cells (immune cells) to kill tumors. It kills some cancers, but not all. Why?

CJ: Often, the tumor cell mutates, so the modified T cells can’t find it anymore. We are now in trials where we give patients a cocktail of cells. Then mathematically, it’s about impossible for the tumor to mutate in so many ways that the engineered T cells can’t keep up. Our end goal is to pin a tumor into a corner, where it can’t escape.

PS: Both CAR T and IMLYGIC use viruses to ignite an immune response. Are there side effects?

CJ: Yes, but we are balancing a sword. In CAR T, patients who get high fevers [from the treatment] are the ones who end up doing best. The fever is your immune response to the virus, which is needed. The patients who never get a fever are the ones who don’t do well.

PS: The big question: Could this lead to a cure for cancer?

CJ: In an ideal world, we will have vaccines. For now, there’s data showing that if we give immunotherapy early, a single treatment could bulk-reduce or eliminate the tumor. And then hopefully it’s one and done.

This article was originally published in the November/December 2016 issue of Popular Science, under the title “Our Bodies Can Kill Cancer.”