title: The success rate of new drug development in clinical trials: Crohn's disease.
abstract: OBJECTIVE
  To determine the risk of drug failure during clinical trial testing in Crohn's disease and determine what steps can be taken to improve outcomes. This is the first study to quantify such risk for a single disease.
  
  
  METHODS
  Moderate to severe Crohn's disease was investigated by reviewing press releases from 1998 to June 2008. Clinical trial failure causes were classified as commercial or clinical and compared with industry expectations. The risk of failure was also reviewed based on whether the compound was a small molecule drug or a biologic. Lastly, the role of the sponsor was examined, in determining whether the size of the firm involved in a drug program was predictive of the outcome of the study.
  
  
  RESULTS
  More than a 120 press releases were reviewed yielding 37 drugs that met our search criteria. The cumulative success rate for drug development in Crohn's disease is 19%, from start to finish of clinical trial testing. New drug approvals are dominated by protein based therapeutics in this indication. Commercial and clinical failures both contributed substantially to the failure rates of new drugs. Phase I clinical testing appeared to offer little risk mitigation with pass rates at 95%.
  
  
  CONCLUSIONS
  Funding intended to advance Crohn's disease must take into account the disease specific historical failure rate of drug development in forecasting any reasonable expectation of producing new therapies. As it currently stands, one in five drugs will be successfully approved that enter clinical trial testing in this indication. To manage this risk continued development of biologics over small molecule drugs may be warranted in this disease.
authors.affiliation: Department of Biology, University of Toronto, Toronto, Canada. jayson.parker@utoronto.ca
authors.forename: Jayson L
authors.initials: JL
authors.lastname: Parker
authors.forename: Jillian
authors.initials: J
authors.lastname: Clare Kohler
mesh_terms: D017321:Clinical Trials, Phase I as Topic / Q000706:statistics & numerical data; D017322:Clinical Trials, Phase II as Topic / Q000706:statistics & numerical data; D003424:Crohn Disease / Q000188:drug therapy* / Q000503:physiopathology; D017277:Drug Approval / Q000706:statistics & numerical data*; D015195:Drug Design; D004345:Drug Industry / Q000191:economics / Q000458:organization & administration; D006801:Humans; D012306:Risk; D012720:Severity of Illness Index; D014481:United States