Some physicians at 18 hospitals were doing just that . And while the trials are blinded , physicians are not blind. They can see a group of people getting shots and not know who got what.
However they will notice that some get better in a much more rapid fashion. Do you honestly think they will see someone get better more quickly than they are used to and surmise they got the placebo. uhhm no, they will think...he got the good stuff.
After the trial was no longer enrolling and they got the EINDs and then the Extension , they knew who was getting Leronlomab, because everybody getting a shot was getting Leronlomab.
After that it's just a shot and then observation.
Those doctors have a very good idea as to whether it works or not.