Sabizabulin's mechanism of action is disruption of microtubules. Which makes sense in relation to fighting Covid. Where the problem lies and I've seen this in other studies is that the death rate in the standard of care arm is abnormally high. Taking into consideration that the patients are a mix of severe and critical at the outside you'd expect a maximum of 30%.

The mortality rate was 20.2% (19 of 94) for sabizabulin versus 45.1% (23 of 51) for placebo. By contrast in leronlimab's trial the mortality rate in the leronlimab arm was 20.5% vs. a mortality rate in placebo of 21.6%.