By Staff Reports
(DGIwire) – Immunotherapy—the method of harnessing the body’s own immune system to attack and kill cancer cells—is not just one of the most exciting frontiers in medicine today; it is now officially Nobel Prize-winning work. As recently reported by the Pancreatic Cancer Action Network and many other media outlets, two pioneers in the field—Drs. James Allison and Tasuko Honjo—were awarded the 2018 Nobel Prize in Medicine. Allison and Honjo each discovered a protein—known as CTLA-4 and PD-1, respectively—that puts the “brakes” on an immune response against cancer cells. They demonstrated that by blocking that braking mechanism, the immune system could theoretically be turned into a cancer-fighting tool.
“The progress that has been made in immunotherapy in recent years has offered tremendous hope to patients with certain cancers,” says Douglas J. Swirsky, the President and CEO of Rexahn Pharmaceuticals. “Patients are living longer and with better quality of life. The challenge that remains is how to extend that benefit to a wider range of patients with different types of cancer. One approach is to combine immunotherapy with other drugs that will directly kill the tumor cells and also sensitize the cells to immunotherapy so that it can work better.”
Rexahn is studying the potential of its compound RX-5902 to treat triple negative breast cancer.
Preliminary data from a study in patients whose cancer had progressed after multiple prior treatments showed encouraging responses, with two patients showing stable disease for longer than 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. In August 2018, the company entered a collaboration agreement to evaluate RX-5902 in combination with immunotherapy (pembrolizumab), in a study in patients with metastatic triple negative breast cancer.
Meanwhile, Rexahn’s other compound, RX-3117, is being developed for pancreatic cancer and for advanced bladder cancer. RX-3117 is unique in that it is activated within a tumor cell by an enzyme that is found in tumors but not in normal tissue. The activated compound then kills the tumor cell after invading its genetic material. RX-3117 is being evaluated in combination with a chemotherapeutic drug in patients with metastatic pancreatic cancer. Preliminary data from the first 14 patients in the study show that RX-3117 is safe and well-tolerated. One patient experienced a complete response after six cycles of therapy; three patients exhibited a partial response, with tumor reduction ranging from 36 to 47 percent; and an additional eight patients experienced stable disease with tumor marker reduction ranging between 43 to 69 percent. The disease control rate for evaluable patients was 86 percent. As for bladder cancer, another study reported that RX-3117 was well-tolerated; one patient showed a complete response, four more had tumor reductions and six others showed disease stabilization for greater than four months.
“The coming years are likely to bring major advances in how we use immunotherapy and other types of cancer treatments and how we can optimally use different combinations of treatments to improve patient outcomes while maintaining a good quality of life,” Mr. Swirsky adds.