FDAAccording to the FDA approval process, it doesn't matter how many times a drug fails to prove useful in its clinical trials. Innumerable scientific studies can show the drug to be ineffective, but as long as two or more show statistical superiority over placebo, the drug can win approval.
I you have some time read about how Prozac got approved... very scary!
In its "Summary of Basis of Approval," dated October 3, 1988, the FDA states that fourteen protocols involving controlled studies were submitted by Lilly. Four compared Prozac to placebo, and of these, three were used by the FDA as evidence of some beneficial effect. One showed none at all. Of the remaining ten studies, eight showed Prozac to have no positive effect. Overall, there were more negative efforts than positive, but this made no difference in the approval process.
In six out of the seven studies where it was included, imipramine (Tofranil), a very old drug, did better than Prozac. That, too, made no difference in the approval process
https://www.sntp.net/prozac/breggin_prozac_2.htm
The FDA allowed Lilly to use the "placebo washout," a very questionable but commonly used technique in drug studies . All patients were started off on placebo for approximately one week (4-14 days). Those patients who showed improvement on placebo were then dropped from the study and the trials were begun all over again from scratch with a placebo and a drug group.
Using the placebo washout helps make a drug seem more effective than it is. For example, some of those patients "washed out" of the testing because they responded positively to the placebo might not have reacted positively to the drug if they had received it in the second part of the testing. That is, if they had not been dropped from the actual trials, the placebo responders might have once again reacted positively to the sugar pill but not to the drug with its frequently unpleasant side effects. Even if the placebo washout reduced the number of positive responders equally in both the sugar pill and the drug groups, this reduction in the total number of positive responders in both groups would favor the drug. Why? Statistically, the same difference between two smaller groups is more significant than. the same difference between two larger groups. The placebo washout purposely produces an unnatural pool of patients. It is unscientific.