The vaccines all target neoantigens, new mutations that are only present on tumors. Aiming at these unique proteins allows the immune system to kill cancer cells while leaving healthy tissue unscathed.To accomplish this, tumors are removed and their genetic makeup is mapped using next-generation DNA sequencing. Companies use artificial intelligence to predict which mutations will be the most effective targets.
At that time, there was already proof that immunotherapy could work in so-called "hot" tumors, or highly mutated cancers, such as melanoma. There was little hope it would work in "cold" cancers with few mutations, such as pancreatic cancer, said MSK's Dr. Vinod Balachandran.
Gritstone Bio is taking a different tack, combining two types of customized vaccines in hopes of treating patients with metastatic colon cancer, another cancer that has been largely unresponsive to immunotherapy. Gritstone is expecting data from a later-stage trial testing its dual vaccine therapy in the first quarter of 2024.