In a perfect world, cancer doesn't stand a chance of wreaking havoc. Like a soldier guarding the home shores, the immune system gives marching orders to white blood cells known as T cells to remain vigilant for an invasion of foreign cells, including cancerous ones. When a T cell recognizes an invader, it initiates a process that targets that cell for destruction.
But cancer is a formidable foe, one that immunotherapy researcher Dr. Stanley Riddell is all too familiar with after more than two decades of attempting to overcome it.
"Tumors are very clever, and they utilize evasion strategies to limit the effectiveness of the immune response," he said.
So he's fortifying the immune system with T cells specially engineered to seek and destroy cancer.
"When you see it work, it is so amazing ― the bone marrow just goes from being full of leukemia to being in remission, and very large tumors simply melt away," Riddell said.
The patients receiving the experimental CAR T-cell therapy through the trial are different from the average leukemia patient — they’ve been through many prior treatments that didn’t work against their cancers, and “they really had very few treatment options at the time they enrolled in our study,” Riddell said.
Using high-tech techniques, Riddell and his colleagues know that the study participants whose cancers disappear after CAR T-cell infusion are in what’s known as a molecular remission, “which is a really, really deep remission, probably remissions that are deeper than anything they’ve ever had with any prior treatment,” the scientist said.
The results so far from this trial are just the beginning, however. Riddell and his team are working on bringing CAR T cells to the clinic that target other types of advanced cancers, including the blood cancer multiple myeloma and solid tumors like breast cancer and lung cancer. The team is also working to overcome common toxic side effects of CAR T-cell approaches, and crafting better CAR technology to reduce patients’ waiting time and increase the cells’ potency against cancer.
“We’re at the starting line,” Riddell said. “But I think we’re at the starting line where we know that we’re in a race that we actually can win.”
Every time he sees patients in the clinic, Riddell goes back to his research with a new sense of urgency.
“The courage of patients is inspiring, and it makes me realize that we don’t have the best [treatments] yet. We have to do better.”
— Updated Dec. 12, 2016