For resistant breast cancers, two drugs may be better than one

Cancer cells are even smarter than scientists previously believed, according to new CU Boulder research. When these cells are confronted with potent new drugs called CDK2 inhibitors, which are designed to prevent cancer from proliferating, they can trigger a workaround to survive the assault in as little as one to two hours. 

But the study, published June 8 in the journal “Cell,” comes with a silver lining. It reveals how cancer cells complete this adaption and shows that simultaneously administering a second, the already widely available drug may hobble cancer cells and shrink resistant tumors. The findings bolster the idea, which is currently under investigation in at least three clinical trials, that when it comes to treating resistant breast cancer, two drugs may be better than one.

The current research suggests that you can potentially have a more effective treatment by combining these new CDK2 inhibitors in clinical development with a drug that already exists. “It also uncovers a very basic, fundamental understanding about how the cell cycle is wired for robustness and why so many tumors manage to proliferate in the face of drugs meant to block proliferation.”

The team is still exploring why that happens, but the researcher suspects that CDK4 and CDK6 may stand in the shadows throughout the cell cycle, ready to jump in and assist when CDK2 is impaired. They said CDK2 inhibitors in combination with CDK4/6 inhibitors could, ultimately, be used to help breast cancer patients that haven’t responded well to existing drugs, as well as those who responded well but then relapsed.

Reference: For resistant breast cancers, two drugs may be better than one; Cell, DOI:10.1016/j.cell.2023.05.013