In all likelihood, only a subset of patients given regorafenib derive benefit, as suggested by the progression-free survival curve seen in the CORRECT trial, according to Dr. Overman.

“This is a very interesting curve. The medians don’t really capture the difference.… If you look more at the area of separation between the two, that’s captured better with a hazard ratio—big difference,” he noted.

“This curve is … reminiscent of another curve that we’ve seen before. That other curve is related to the experience we have had with anti-EGFR antibodies. This is actually a curve pulled from panitumumab [Vectibix] vs best supportive care prior to any knowledge about KRAS. And this shape of the curve is a subset effect,” he explained, whereby patients with wild-type KRAS benefit, but patients with mutant KRAS do not.

“This is the same thing we are seeing with regorafenib—likely a population that is getting no benefit and a population that is getting benefit,” Dr. Overman asserted. “One of the problems we have right now is we have no way to determine what that population is. So that’s a very interesting area for us to explore and try to sort out.” ■