A study published in the journal Science revealed that Pfizer's early-stage pancreatic cancer candidate CP- 870,893 shrank tumors in four patients in the study. An additional 11 patients saw their tumors stabilize. The participants were given Pfizer's drug in combination with Eli Lilly's Gemzar chemotherapy, notes Bloomberg. The combination therapy prevented disease progression for an average of 5.6 months, as compared to just 2.3 months for those on chemotherapy alone.
When researchers biopsied tissue samples from those receiving the treatment, they found something surprising: CP- 870,893 didn't work they way it was engineered to. Instead of activating the immune system's T-cells to attack the tumors, the treatment caused white blood cells to attack the cancer. Macrophages, as they are called, usually protect cancer tumors.
"Until now, we thought the immune system needed to attack the cancer directly in order to be effective," lead author Robert Vonderheide, a cancer professor at the University of Pennsylvania, told Bloomberg. "We think that this may be a general approach for treating other types of solid tumors."
Studies for CP- 870,893 in melanoma are already under way. And researchers plan to study how they can boost the microphage response to further shrink tumors.
- read the Bloomberg article