Preclinical
Everything done to a potential drug before it is given to a human: lab experiments, animal testing, and the safety and manufacturing work regulators require. Most candidates never make it out.
Preclinical development establishes that a drug hits its target, kills or slows tumours in cells and animals, can be made consistently, and is safe enough at the planned dose to test in people; toxicology in two species is normally required before the first human trial. 'Preclinical evidence' on this site means a claim supported only by such work, and the reader should discount it heavily: roughly 90% of drugs that enter human testing fail, and preclinical findings often do not reproduce even in other labs. Better models (organoids, humanised mice, patient-derived xenografts) and more rigorous reporting are attempts to shrink the gap between bench and bedside.