The latest research presents a possible explanation for why a new type of cancer treatment has not been working as anticipated against bladder cancer. The research finds that checkpoint immunotherapy, which is supposed to activate the immune system, is ineffective on some bladder cancers because there are no immune cells in the tumors. The finding clarifies what is happening at a cellular level to prevent the immune cells from getting into the tumor and points researchers in the right direction towards developing a mixture therapy that could work.
Daugaard, a senior scientist at the Vancouver Prostate Centre, said it has already been a mystery for many years as to how tumors evade the immune system. He continues his word by saying “We have found a cellular pointer pathway that controls whether the body’s immune cells are allowed to infiltrate the tumor.”
Bladder cancer is the 5th most prevalent cancer in the World. There is only one line of chemotherapy available, cisplatin-based therapy, for invasive tumors. Once cancers become absorbent, only checkpoint immunotherapy is endorsed as a second-line treatment.
Atezolizumab is a checkpoint immunotherapy drug that strengthens the body’s immune response and currently became the first new bladder cancer drug to be endorsed in more than two decades. Primary results were auspicious, but subsequent scientific trials have shown that only one in five patients proved an objective response to treatment. The reason for that has baffled researchers, until now.
In this research, Daugaard and Dr. Peter discovered that some invasive bladder cancer tumors block the immune cells from accessing it by activating a cell pointer pathway called the peroxisome proliferators-activated receptor gamma (PPAR-γ) pathway.
“With this pathway, the tumors close the door to the immune system,” said Daugaard. “Without immune cells in the tumor, checkpoint immunotherapy has little effect. Now we know what door the tumors are closing, and we can, therefore, focus our efforts on deteriorating that door and let the immune system back in.” added by Daugaard.
Daugaard and his team have taken the first steps to develop a drug able to target the PPAR-γ pathway. The main reason is to use such a drug in combination with checkpoint immunotherapy treatment.
“The best way to resist cancer would be to have the immune system take care of it. In fact, that is what we want to accomplish,” said by Daugaard.