A new cancer vaccine is moving into phase 1 human trials after promising results from animal studies showed encouraging efficacy and a robust safety profile. A new study describes the vaccine as producing complete responses in 90% of animals when combined with a second immunotherapy drug.
The development of immune checkpoint inhibitors it is perhaps the biggest breakthrough in cancer therapy in the last two decades. These treatments focus on blocking the mechanisms used by tumor cells to evade attack by immune cells. And they are behind the development of PD1-Vaxx, an experimental cancer vaccine.
The role of the PD-1 protein
One of these mechanisms is that tumor cells attack a checkpoint protein, PD-1, to cancel the immune response. When this PD-1 protein binds with PD-L1, another checkpoint protein found on healthy cells and some tumor cells, it is able to give killer immune cells a sort of “green light”. Killer immune cells pass by and don't do their job.
PD-1 inhibitors are a relatively new class of drugs that allow killer immune cells to more effectively detect and kill cancer cells. In recent years, several first generation anti-PD-1 monoclonal antibodies have been approved for the treatment of several tumors. This new therapy, a true cancer vaccine called PD1-Vaxx, is designed to trigger a broader polyclonal antibody response, with hopefully better efficacy than the first generation of checkpoint inhibitors.
How does the PD1-Vaxx cancer vaccine work?
Two fundamental ideas
This new study, led by Ohio State University researchers, reports preclinical testing of PD1-Vaxx in combination with a second immunotherapy treatment. The first author of the study, Pravin Kaumaya, says this new research offers two important insights into how the new cancer vaccine works.
"First, PD1-Vaxx activates the functions of both B and T cells to promote tumor elimination,” says Kaumaya. “Secondly, treatment is aimed at blocking signaling pathways crucial for tumor growth and maintenance. By giving this vaccine in combination with an immunotherapy drug, we are essentially directing the immune system to target and kill cancer cells.”
The researchers report that the combination therapy was tested in an animal model of colon cancer and produced complete responses in nine out of 10 animals. Previous preclinical tests have effectively established a robust safety profile for the cancer vaccine.
The FDA has approved the move to human trials
In early November, the U.S. Food and Drug Administration granted approval to PD1-Vaxx to advance to Phase 1 human trials. “We are excited to begin testing this vaccine in the United States to provide new hope for patients with lung cancers and other cancers,” Kaumaya says.
The new research was published in the journal Oncoimmunology.
