An unforgiving enemy
To guide her treatment, Blechner turned to doctors at Memorial Sloan Kettering Cancer Center, including Dr. Vinod Balachandran, director of MSK’s Olayan Center for Cancer Vaccines.
It’s more challenging to make a vaccine against cancer than it is to create a vaccine against a virus or bacteria, Balachandran says. “That’s because our body’s immune systems are hard-wired to recognize viruses and pathogens as foreign, so a vaccine is teaching our body to do something it already wants to do. In contrast, cancer is ourselves. It’s derived from our own tissues.”
Much of Balachandran’s work the past two decades has focused on pancreatic tumors because the disease is such a tough nut to crack. “It’s a cancer where nothing had really worked,” he said.
When Blechner arrived at MSK, he was just launching a trial of an experimental mRNA-based vaccine against pancreatic cancer, in combination with standard immunotherapy and chemotherapy. He felt like a successful vaccine would also have the potential for wider application. “If we could break through and crack the toughest one, it could unlock how to crack the other [types of cancer], because it would provide a blueprint.”
To develop the vaccine, he began by studying “super-survivors”: the fewer than 10% of pancreatic cancer patients who live more than five years from the time of diagnosis. He found that their immune systems were especially good at spontaneously recognizing cancer cells as foreign. In fact, Balachandran says, these patients had about 12 times as many T-cells – a specialized type of immune cell – inside their tumors as average patients. The same T cells were circulating for more than a decade, in some cases.
Balachandran also realized that these weren’t generic cancer-fighters. “These T cells were recognizing mutations,” he said, “but each person’s immune system was recognizing their cancer as foreign in a very specific way. To replicate this would require us to teach each individual person’s immune system how to recognize their individual cancer. It would be an individualized vaccine. And we felt the best technology for rapid custom cancer vaccination was to use RNA.”
Taking a chance as a research volunteer
After Blechner signed on for the trial, the first step was surgery. She underwent what’s known as a Whipple procedure to remove the tumor in the head of her pancreas. In a lab at MSK, the tumor was preserved and sliced into fine pieces, each thinner than a human hair. In less than 72 hours, the package was en route to Germany, where technicians at BioNTech took steps to process the material into a clear liquid: a personalized vaccine, custom-made for Vita Sara Blechner.
