I think most AIDS patients would gladly take that 10% chance.
Here is a hypothetical example (because I don’t know much about HIV): Getting rid of frequent headaches (the hypothetical side-effect of managing a hypothetical otherwise deadly disease) with a cure that has a 1:5 chance of death doesn’t seem like a good deal to me.
HIV may not be a death sentence anymore, but it's still a serious disease with profound implications in one's lifestyle, and as far as I'm concerned, a cure can't come soon enough.