In 2010, DiMasi et al1 analyzed clinical approval success rates and clinical phase transition analyses for the investigational compounds that entered clinical testing between 1999 and 2004 with confidential data from the 50 largest pharmaceutical firms. Only 16% of compounds entering clinical testing eventually gained marketing approval. Most failures occurred in phase 2 and 3 trials, which is not surprising because phase 1 trials are focused on screening for safety and dosing, whereas phase 2 trials focus on establishing efficacy and phase 3 trials focus on confirming safety and efficacy. In view of the fact that the decision to test a compound in clinical trials involves extensive consultation among experienced scientists and clinicians, an overall 84% failure rate (from phase 1 to new drug application approval) seems remarkably high. Some direct consequences of this high failure rate are reduced output of new treatments for our patients and a higher cost of pharmaceutical and biological agents. (The profits from 1 successful compound must cover the losses incurred from 5 failures.) Because funding for medical care is increasingly constrained, an indirect consequence of this failure rate also may be reduced reimbursement for physician services and reduced access to care. Thus, improving the efficiency of product development is a matter of great importance.
Zarbin MA. Translating Drugs From Animals to HumansDo We Need to Prove Efficacy?. JAMA Ophthalmol. 2014;132(6):667-668. doi:10.1001/jamaophthalmol.2014.882