Well-conducted Phase II clinical trials provide the data required to determine whether there is a case to be made, both scientifically and commercially, for progressing a drug candidate into Phase III trials. At present, however, Phase II success rates are lower than at any other phase of development. Analysis by the Centre for Medicines Research (CMR) of projects from a group of 16 companies (representing approximately 60% of global R&D spending) in the CMR International Global R&D database reveals that the Phase II success rates for new development projects have fallen from 28% (2006–2007) to 18% (2008–2009), although these success rates do vary between therapeutic areas and between small molecules and biologics. As the current likelihood of a drug successfully progressing through Phase III to launch is 50% (Nature Rev. Drug Discov. 10, 87; 2011), the overall attrition of late-stage drug development seems to be unsustainably high.
Although it is difficult to draw conclusions from these data, the finding that a substantial proportion of Phase II failures were due to strategic reasons suggests that one important underlying factor could be overlapping R&D activity between companies with drugs in Phase II trials. This raises the question of whether an increase in collaborative efforts between companies up to the point of proof-of-concept for novel targets or mechanisms might be more cost- and time-effective.
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