I would like to answer the original question and add the points about general clinical trials without the animal studies that have not been mentioned.
“how can you possibly predict that beforehand”? we don’t. There can always be an unforeseeable risk that we hope it will not be there. In all the studies that I have worked in, there was always this line in the consent form. All clinical studies I participated in weren’t required to have animal study because the risk was minimal and the animal model was not appropriate/translatable. Although we always include the may-seem-rare risk that can happen (for example subject has to stand so there’s a fall risk), there can always be other risk lurking around so we just have to be cautious with each step of the process.