That's a reasonable way to look at this, in principle. But I don't see why you put chances of success so low. To justify that on the basis of general statistics on success of trials is not sufficient. What perils do you see confronting NNVC in it's flu trials? Unlike almost all other "drugs" we have something here that does not seem to interact in any significant way with a living biological system. It will be cleared from the circulatory system eventually, and that clearing process might cause problems. But it has not done so in animal testing. The viricides might survive and be excreted into the waste stream causing some kind of adverse ecological effect. But what if any evidence is there that suggests that might happen? The viricides might escape the circulatory system and enter cells causing adverse effect. But that did not seem to happen in animals, so what's different about humans? All this suggests to me a very low possibility of failure. Where do you come up with 60% failure probability. I can't get a number that high.