The study was not "stopped". They removed the high dose arm because of these issues and continued with the low dose arm, although at least one source (Biocentur

The study was not "stopped". They removed the high dose arm because of these issues and continued with the low dose arm, although at least one source (Biocentury) called the emergence of the toxic effect "stastistically insignificant trend". Which doesn't mean that it's not bad (it is), but that you can't rule out the null hypothesis there (assuming that what Biocentury wrote was correct). I don't know enough on the safety profile of hydroxychloroquine as opposed to chloroquine to tell if they're different on that regard (the French institution in Marseille uses the latter, IIRC). Any pointers on that?