Cancer’s Newest Miracle Cure

It combines the power of genetics and the immune system, and it’s saving lives

Diagnosed with leukemia when she was 18 months old, [Kaitlyn Johnson’s] life has been consumed with cancer treatments, doctors’ visits and hospital stays.

Acute lymphoblastic leukemia is the most common cancer among young children, accounting for a quarter of all cancer cases in kids, and it has no cure. For about 85% to 90% of children, the leukemia can, however, be effectively treated through chemotherapy.

If it is not eliminated and comes back, it is, more often than not, fatal. Rounds of chemotherapy can buy patients time, but as the disease progresses, the periods of remission get shorter and shorter. “The options for these patients are not very good at all,” says Dr. Theodore Laetsch, a pediatrician at the University of Texas Southwestern Medical Center.

When Kaitlyn’s cancer wasn’t controlled after three years and round after round of chemotherapy drugs, her doctors had little else to offer. “They said, ‘This did nothing, it didn’t touch it,’” says Kaitlyn’s mother Mandy, a dental assistant from Royce City, Texas. “My stomach just dropped.” Kaitlyn could receive a bone-marrow transplant, but only about half of those procedures are successful, and there was a good chance that she would reject the donor cells. If that happened, her chances of surviving were very small.

In a calculated gamble, her doctors suggested a radical new option: becoming a test subject in a trial of an experimental therapy that would, for the first time, use gene therapy to train a patient’s immune system to recognize and destroy their cancer in the same way it dispatches bacteria and viruses. The strategy is the latest development in immunotherapy, a revolutionary approach to cancer treatment that uses a series of precision strikes to disintegrate cancer from within the body itself. Joining the trial was risky, since other attempts to activate the immune system hadn’t really worked in the past.

What are we going to do if this doesn’t help her?”

But it did. After receiving the therapy in 2015, the cancer cells in Kaitlyn’s body melted away. Test after test, including one that picks up one cancer cell in a million, still can’t detect any malignant cells lurking in Kaitlyn’s blood. What saved Kaitlyn was an infusion of her own immune cells that were genetically modified to destroy her leukemia. “You take someone who essentially has no possibility for a cure–almost every single one of these patients dies–and with [this] therapy, 90% go into remission,” says Dr. David Porter, director of blood and bone-marrow transplantation at the University of Pennsylvania. Such radical immune-based approaches were launched in 2011 with the success of intravenous drugs that loosen the brakes on the immune system so it can see cancer cells and destroy them with the same vigor with which they attack bacteria and viruses. Now, with the genetically engineered immune cells known as chimeric antigen receptor (CAR) T cells that were used in Kaitlyn’s study, doctors are crippling cancer in more precise and targeted ways than surgery, chemotherapy and radiation ever could. While the first cancer immunotherapies were broadly aimed at any cancer, experts are now repurposing the immune system into a personalized precision treatment that can not only recognize but also eliminate the cancer cells unique to each individual patient.

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