By Jenna Larson
Using new techniques that tap into the defense mechanisms of the immune system, doctors are able to decloak — or weaken — cancers, in hopes of purging them altogether.
“One of the really exciting areas that we are working on is the use of the immune system to treat cancer,” said George Weiner, the director of the University of Iowa Holden Comprehensive Cancer Center.
For many years, one of Weiner’s focuses at the center has been using the immune system to treat cancer.
“I think we have finally, after struggling and doing a lot of research on how the immune system works, got to the point where we can use the immune system to treat cancer,” he said.
Teams at the center are working to ensure that this new treatment is working safely and effectively on patients, he said.
“It’s a new era in cancer therapy,” he said. “It’s very exciting, but we have a lot of progress to make.”
Doctors and researchers have been working on changing the tumor itself so that the immune system sees it as foreign, Weiner said. They are looking at ways to inject cancer-fighting proteins or other drugs into the tumor so the immune system realizes it doesn’t belong there.
“We are combining this with the check-point blockade breakthrough that allows the immune system to continue to fight the cancer once it recognizes it as foreign,” he said.
One thing researchers are doing is injecting fake viruses into the tumors. These viruses aren’t infectious but will activate the immune system to fight back, Weiner said.
Compared to such standard treatment as chemotherapy, the new technique of approaching the tumor through the immune system is more targeted.
“With these new approaches, we are really focusing on what’s different from the cancer cells to the normal cells,” he said.
The new approaches should allow the therapy to be more effective than typical treatments and have fewer side effects.
“Our goal is to reduce the need to use these standard approaches to cancer therapy by developing these targeted approaches,” Weiner said.
Along with these viruses injected into the tumor, there are also drugs that can break tolerance between the cancer cell and the immune cell, said UI Clinical Professor Mohammed Milhem.
“There are many categories of new drugs that have come out [to attack cancerous cells],” he said. “Some of them are oral, IV, [or] direct injections.”
The method of injection is determined by the type of cancer, he said. For example, melanoma is a surface cancer, so injection is a somewhat easier approach.
“We are still trying to figure out how [injection] would apply to other cancers,” Milhem said.
Also, the immune system’s response is not specific to any particular type of cancer, but rather, it can kill all types of cancers, he said. Cancers can engage the immune system faster and better so it can kill them in a more robust way, or vice versa.
“Some of these direct injections have potential in making tumors that might turn [unrecognizable] into [recognizable],” Milhem explained.
Anti-programmed death-1, a protein injected to target the tumor through the immune system, has been popular in treating melanoma and lung cancer, Milhem said.
“In melanoma, kidney cancer, and pretty much all other tumors, the hot topic is Anti-PD-1,” said Yousef Zakharia, a UI clinical assistant professor of hemotology/oncology.
The cancer center is holding numerous trials to test the efficacy of these agents with other types of treatments, he said.
“The combination of two agents improve the overall response rate of patients,” he said. It also is much more tolerable.
Teams at the center who are conducting these clinical trials are seeing robust results with response rate and survival of patients.
“The field is moving away from chemotherapy and going toward an immunotherapy approach,” he said.