Increasing Percentages of New Drugs are Failing Phase II and III Trials

In the drug discovery pipeline, Phase I trials are first used to evaluate if a new drug is safe, then Phase II trials are done to assess the drug’s efficacy, and finally Phase III trials are performed to monitor side effects and compare the drug to similar compounds already on the market. Each consecutive phase includes more people to refine the results obtained in the previous phase. A recent analysis by the Centre for Medicines Research in the UK has concluded that since 2008, the failure rate for drugs in Phase II and III clinical trials has been rising [1-2]. Phase II success rates are currently at 18%, lower than at any other phase of drug development.

Drug development pipeline