The field of immunotherapy is booming. There are more than 2,600 clinical trials currently testing the most effective kind of immunotherapy, but only about 89, or 3%, of those studies are focused on pancreatic cancer. Why is pancreatic cancer so difficult to treat, and why don’t many immunotherapy researchers study it?
Because pancreatic cancer is one of the deadliest cancers, currently ranking as the third leading cause of U.S. cancer-related deaths, people are wondering why immunotherapy researchers aren’t doing more to study the disease.
Checkpoint inhibitor therapies like Keytruda (pembrolizumab) have been very successful at treating several different kinds of cancer. Clinical trials have subsequently been testing drugs like Keytruda to determine how to make the treatment more successful. But much of this research remains targeted to similar cancer types, such as lung and bladder. Why is there such a disparity?
Pancreatic cancer is not very “immunogenic,” meaning that it doesn’t really trigger the immune system. This is partly why it’s so difficult to use immunotherapy against the tumors. Lung cancer, kidney cancer, and melanoma are, on the other hand, extremely immunogenic, which is why immunotherapy treatments have been so successful in treating them.
The cells surrounding pancreatic tumors are also more likely to block immune responses, which makes it even more probably that cancerous cells will escape the immune system’s attack.
The 89 studies that are focused on pancreatic cancer are working to try different drug combinations with the aim to find one that works. Some studies are also testing drug combinations combined with standard treatments like chemotherapy.
One study, the Parker study, has produced some positive results. Two out of the four study groups received gemcitabine plus Abraxane with an investigational immunotherapy that blocks a protein called CD40. The other two groups received Bristol Myers Squibb’s Opvido along with the therapy.
At the annual meeting of the American Association for Cancer Research last weekend, researchers reported that the treatment has improved tumor shrinkage in 24 (58%) of the patients. Some patients experienced serious side effects from the treatment, however.
The trial has been successful enough that it will move into Phase 2, which is great news. It is the hope of these researchers that their treatment will be successful enough to add to the other effective immunotherapy treatments approved by the FDA.