When you (or Otto Yang) say Leronlimab is only "50%-75% effective", there is no context to that statement. Effective at *what*? Adding muscle mass? Growing hair? Eliminating body odor?
The trial was designed with a primary end point of mortality after 28 days. Meaning if Leronlimab prevents a patient from dying within 28 days, it was effective. If 50%-75% of the patients were dying before 28 days at the midpoint review, the DSMC would've stopped the trial. By the calculations I've seen, there can only be at most around 50 deaths in the Leronlimab arm and still meet efficacy.
So, yes, if the trail was designed with an endpoint of preventing ARDS or eliminating myalgia, maybe Leronlimab would be only 50%-75% effective. But as indicated by the DSMC recommendation to continue the trial unchanged, it will be MUCH more effective in preventing death.