"Even when we were very conservative [with our estimate], the cost of a course of these treatments would be on the order of $150 to $250 per person," Hill says. He questions whether the $84,000 price tag represents "a fair profit."

She notes that Gilead more than $11 billion to acquire a smaller company that developed sofosbuvir. She acknowledges that Gilead should be allowed to recoup that investment.

On the other hand, "you only need about 150,000 people to recover that cost," Graham says. "And so, if you're treating 2 million people, once you have recovered your cost, then I think it's ... I don't want to say it's unfair, but it does start feeling more exploitative."

'An Affordable Range'

Graham says she thinks once Gilead has recovered its investment cost, it ought to cut the price of sofosbuvir.

"That's very unlikely that we would do that," responds Alton, Gilead vice president. "I appreciate the thought."