The failure in humans of stuff that worked in mice is actually the biggest driver of the cost of drug development According to a widely cited paper on the cost

The failure in humans of stuff that worked in mice is actually the biggest driver of the cost of drug development According to a widely cited paper on the cost of drug development [0], phase 2 has the lowest probability of succes of any stage in the funnel at 30-40%. Phase 2 is generally the first time a drugs effectiveness is studied in humans. It can cost $50-100M+ to get a drug through a phase 2 study One of the major advances in drug development in the last few years is to reduce the "translational risk", i.e. The risk that animal models and other disease models are not predictive of human outcomes. A recent study suggests that we have actually started to make some improvements in this area which is a huge step in lowering drug costs and getting more new medicines [0] https://www.nature.com/articles/nrd3078 https://www.nature.com/articles/nrd3078