What’s Best for Breast Cancer: The Possibilities of Enhancing Immunotherapy

(DGIwire) – Could the advent of immunotherapy mean a brighter future for breast cancer treatment? As recently noted in an article in TIME magazine, many researchers think it might. They have set their sights on finding ways to retrain the body to recognize and destroy tumor cancer cells—a strategy that is making immune-based treatments the newest and most promising weapon against many types of cancers, including certain types of breast cancer that are difficult to treat.

Yet the article acknowledges that, while immunotherapy has shown successes in certain types of cancers (such as leukemia and other blood cancers), there has been relatively less success treating solid cancers—the category into which breast cancer falls—for a variety of scientific reasons. As a result, some researchers are experimenting with ways to combine newer immunotherapy drugs with conventional treatments, such as chemotherapy and radiation, with the hope that the synergistic effect will make tumors more vulnerable to attack by the immune system.

“Combination treatments represent an innovative potential tool in the treatment of breast cancer,” says Douglas J. Swirsky, President and CEO of Rexahn Pharmaceuticals. “Apart from using chemotherapy and radiation, researchers are studying the effectiveness of other small molecules with novel mechanisms of action that are capable of killing breast cancer tumor cells while leaving the surrounding healthy tissue intact.”

One of Rexahn’s compounds, RX-5902, is in studies for triple negative breast cancer, which is an unusually aggressive form of breast cancer that doesn’t respond to hormonal treatment or other standard treatments for breast cancer. RX-5902 inhibits a protein that is responsible for cancer cell growth and metastases and that also allows the cancer cell to evade the body’s immune system that is designed to kill cancer cells.

Rexahn recently reported initial data from a clinical study in metastatic triple negative breast cancer, showing that RX-5902 was safe and well-tolerated in patients who had undergone extensive prior treatment but who had failed two or more of those earlier therapies. Preliminary data showed encouraging responses in heavily pretreated patients, with two patients showing progression free survival of greater than 200 days. Notably, one subject—a 78-year-old woman with malignant neoplasm of the right breast who had progressed on all of her previous therapies—showed an overall tumor reduction of more than 18 percent.

Rexahn also plans to study RX-5902 in combination with immunotherapy. In August 2018, the company announced a collaboration agreement to evaluate the combination of RX-5902 and an immunotherapy drug, pembrolizumab, in a Phase 2 study in patients with metastatic triple negative breast cancer.

“Triple negative breast cancer is an aggressive form of breast cancer that is very difficult to treat,” Mr. Swirsky adds. “There is tremendous need for more effective treatments. The approach of combining immunotherapy with other treatments that can improve the efficacy of immunotherapy has the potential to significantly improve outcomes for patients without the side effects seen with standard chemotherapy.”