New Drug Stunts Tumor Growth

By: Erika Dunayer, Ivanhoe Health Consultant

(Ivanhoe Newswire) -- Cancer is a leading cause of death globally. Now, researchers are breaking ground on new ways to cut off the ability for cancer cells to grow.

RNA Polymerase I (Pol I) activity is essential for cancer cell survival. Scientists are discovering that its inhibition selectively activates p53 (tumor suppressor protein) to kill tumors. Cylene Pharmaceuticals, founded by Daniel Von Hoff the worlds leading clinical oncologist, has found that the Pol I inhibitor, CX-5461, selectively destroys cancer by activating p53 in malignant cells but not in normal cells.

"What we found is that the drug (CX-5461) can selectively kill the tumor cells. It activates p53, which is the guardian of the genome, activating p53 is something everyone strives for, and as it turns out, that’s how this drug works," Dr. William G. Rice, PhD, President and CEO of Cylene Pharmaceuticals, told Ivanhoe.

"We collaborated with the team at the Peter MacCallum Centre in Melbourne, Australia and together we validated that Pol 1 is a true target for cancer. Even a modest reduction in Pol 1 selectively kills cancer cells but not normal cells and that was really a major finding to show that you can reduce Pol 1 in cancer cells and it kills them but it does not kill normal cells," Dr. Rice said.

Studies were done in vivo (within the living) models of blood cancers and demonstrated that the drug removed malignant cells from the bloodstream, while allowing normal healthy blood cells to grow, thus differentiating CX-5461 from genotoxic treatments. Targeting cancer's dependence upon Pol I to trigger cancer-specific activation of p53 signifies an entirely new approach to cancer therapy.

"It's a completely new concept to treating cancer," Rice told Ivanhoe. "Identifying the target (Pol 1), understanding that it is a validated cancer target, developing the drug, showing that it selectively kills tumor cells and not normal cells, and now we have even been able to determine genetic marker cells which means that we will be able to select the most beneficial patients. It is unusual to have all of those elements meet at one time."

This drug will be clinically tried in human patients in just a couple of months. The Peter MacCallum Cancer Center in Melbourne Australia received a grant from the Australian Government to support this first-in-human trial.

"It's a major step forward to be able to move this into humans so quickly and we are just thrilled to be able to offer a new class of drugs to cancer patients. We really have the potential here to save lives and that is very exciting," Rice said.

Source: Ivanhoe Interview with Dr. William G. Rice, PhD, President and CEO of Cylene Pharmaceuticals on July11, 2012