Drugs blocking tumor proteins offer hope for cancer outcomes

This blog post is by Timothy Cannon, MD.  Dr. Cannon and other members of the Inova Dwight and Martha Schar Cancer Institute will be blogging on current topics in cancer, research and other developments of note. 

A personal story always adds to the drama of a clinical trial. In this week’s issue of The Journal of Clinical Oncology, a group of researchers describe the response of renal cell carcinoma (kidney cancer) to a type of treatment called an immune checkpoint inhibitor.

(Click here to see the abstract; Full article: Survival, Durable Response, and Long-Term Safety in Patients With Previously Treated Advanced Renal Cell Carcinoma Receiving Nivolumab.)

Of the 34 patients studied, 29% had a significant shrinkage, while many others were able to maintain stable disease. Importantly, as described in the article via the anecdote about Philip Prichard, those who do respond often have a dramatic and long-lasting response. Stories of prolonged complete remissions are now ubiquitous in the medical literature.

As a hematology fellow in 2008, I first learned about experiments in rats that demonstrated that a medicine could uncloak a cancer, and allow it to be recognized by the immune system. Tumors secrete proteins such as PD-1 (programmed death-1) that hide the tumor cells from one’s immune system, allowing the tumor to grow unrecognized.  I was fascinated by this idea, but wondered if blocking one such protein would really make a meaningful difference in the outcomes of human beings with cancer. In the past several years, my skepticism has been allayed by multiple wonderful clinical trial results. Though they don’t work for everybody, the story in this article gives us a taste of their potential. An important future goal will be distinguishing those patients who will benefit from the drug, from those who will not.