Narrator: This is Science Today. For the first time, a virus that's been engineered to selectively kill cancer cells, is advancing to a clinical trial known as Phase 3, which determines whether or not the treatment can be used in clinical practice. Dr. Frank McCormick, who directs the University of California, San Francisco Cancer Center, developed the virus being used, which is called Onyx-015.
McCormick: It's definitely been clear for quite a long time that viruses do have some preference with replicating in cancer cells and that people have tried before, way back, to do this kind of thing. But this is the first specifically engineered virus that's gone this far.
Narrator: Onyx-015 is an adenovirus, one of the causes of the common cold. But it lacks a specific gene that neutralizes a tumor suppressive protein called p53, which is also sensitive to viral attack in normal cells. But cancer cells, for the most part, lack functional p53.
McCormick: By taking out the gene that neutralizes p53, we've made a virus that can only grow in cells that don't have any p53. The results we've attained so far are encouraging and promising, but we haven't formally begun to prove that this is having a clinical benefit.
Narrator: For Science Today, I'm Larissa Branin.