Giving Immunotherapy and Chemotherapy a Molecular Boost

(DGIwire) – Immunotherapy has shown great promise in cancer care. However, not all patients respond to it—spurring a search for ways to make it more effective. One of the most intriguing strategies involves so-called “combination treatments” in which immunotherapy and chemotherapy are given in tandem with additional agents. In recent years, researchers have identified several compounds that not only kill cancer cells but are able to do so while leaving healthy cells alone.

“Combination treatments offer what some believe is a promising strategy to move the success rates of cancer treatments forward,” says Douglas J. Swirsky, President and CEO of Rexahn Pharmaceuticals. “We have identified two compounds in particular that are designed to block biological pathways that are present in cancer cells and that are involved in the growth and proliferation of tumors.”

A recent R&D magazine article discussed the potential of this research. Rexahn is studying the potential of one compound, RX-3117, to treat pancreatic cancer and advanced bladder cancer, and another compound, RX-5902, to treat triple negative breast cancer. As Mr. Swirsky notes, both compounds have been well-tolerated by patients in studies to date.

RX-3117 is activated within a tumor cell by an enzyme that is overexpressed in tumors but limited in normal tissue. The compound then kills the tumor cell after invading its genetic material. Rexahn is evaluating the combination of RX-3117 and a chemotherapeutic drug in patients with metastatic pancreatic cancer. Preliminary data 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.   Meanwhile, in bladder cancer, another study reported that RX-3117 was well-tolerated; one patient showed a complete response, four more had partial tumor reductions and six others showed disease stabilization for greater than four months.

As for RX-5902, initial data from a study in metastatic triple negative breast cancer showed 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, with two patients showing stable disease for longer 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.

“The future of immunotherapy might include more combination treatments that help ensure the best possible outcomes for a wide range of patients in need,” Mr. Swirsky adds.

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