OCRF Research Explains Limits of Cancer Immunotherapy Drugs

A new study of ovarian cancer cells from the University of Michigan Comprehensive Cancer Center, funded in part by an OCRF grant to Dr. Weiping Zou, reveals molecular changes within the tumor that prevent immunotherapy drugs from killing off the cancer.  The research was published in Nature.

Immunotherapy treatments have proven wildly successful in treating some patients with cancer. But despite this success, many patients do not respond to the treatments.  Researchers hope the new findings will help make the treatments more effective over time.

The team of researchers studied why certain tumors were able to evade immune therapies designed to unleash the body’s defenses to fight cancer. They noted that tumors with a high concentration of “T cells,” a type of white blood cell essential to the human immune system, were more responsive to the treatments. Tumors with a low number of T cells inside what researchers call the “cancer microenvironment” were far less responsive to the new drugs.

“The tumors are acting to protect themselves,” said Weiping Zou, a senior author of the study and a professor of surgery, immunology and biology at the University of Michigan’s medical school. “If the T cells cannot get in, they have no way to kill the tumors.”

Using human and mouse models of ovarian cancer cells, he and other scientists experimented with specific drugs aimed at helping generate more T cells within a tumor, so that it would then be more responsive to immunotherapy. Although it’s early, the approach seems to have promise.

The main obstacle has been the realization that some cancers have proved less susceptible to immune therapies, and some patients have fared far better than others. If researchers such as Zou and his colleagues can engineer ways to make game-changing immune therapies effective in more patients, that would be a game-changing feat.

“How can we make the responders more responsive, and make the non-responders become responders?” Zou said. “That’s the whole goal.”

Excerpted from The Washington Post.  Click here to read more about this research.