If only that was all you had to show in the preclinical stage.<p>The bigger problem is you can’t show either of these with preclinical testing. If you could then there would be no need for human testing.<p>The reality is most of preclinical testing outside of certain drug classes (e.g. antibiotics) is not that helpful for knowing if a drug will cause problems in humans or will even work. It has got so bad that most drugs on the market would not get through current preclinincal testing requirements.