"At least one other protease inhibitor that was targeted against hepatitis C has failed in development, largely because it had too many side effects.
To investigate when they failed in development, we fixed timed collections and stained them for DNA, tubulin, and the centrosomal marker Cnn.
Male Wistar rats received pharmacologically active doses of 14 compounds that had failed in development owing to hepato- and/or nephro-toxicity.
There have been numerous assays developed in order to pre-screen compounds that would likely fail in further development due to poor absorption properties including PAMPA, Caco-2, and MDCK permeability assays.
Even ENMs intended for biomedical applications often fail in preclinical development due to endotoxin.
In clinical oncology, most drugs fail in late development after enormous financial investments, typically due to a lack of efficacy in human subjects.
It is thus imperative that compounds brought forward do not fail in late stage development and the two features that have a major impact are pharmacokinetics and toxicity.
Even worse, up to 83% of the drug candidates which are successful in pre-clinical tests fail in the clinical development phase where the drug candidate is tested in human volunteers and patients, and a still significant proportion fails in the most expensive late pivotal trials.
