Last year, a new drug called Zaltrap was approved as a kind of last-chance therapy for patients with colorectal cancer. Studies suggested Zaltrap worked almost exactly as well as an existing drug called Avastin. In fact, the main difference between the two drugs seemed to be the price. "I was rather stunned," Dr. Leonard Saltz, who specializes in colorectal cancer, told me. Zaltrap costs about $11,000 per month — about twice as much as Avastin, Saltz said. Saltz and his colleagues at Memorial Sloan-Kettering Cancer Center in New York made what seemed like a very reasonable decision: The hospital would not stock the more expensive drug. But taking cost into account for a new cancer drug was a very unusual decision for the hospital