Here comes the hard part -- figuring out the percentage of prostate cancer patients who fit that category, which is labeled "AIPrC" in my model above. After a lot of Googling and research, including looking back at some old analyst notes, my best guess is that 35% of prostate cancer patients are no longer responding to hormone treatments. That's what I used in my revenue model to come up with a total population of AIPrC patients -- the target group for Provenge.