According to a recent Cytel Whitepaper on Adaptive Clinical Trials, 50% of Phase 3 trials eventually fail. This new Cytel Infographicoffers a breakdown of why so many drugs fail in Phase 3.
The infographic demonstrates that while 42% of failures are economic (e.g. uncompetitive from the perspective of safety and efficacy), 45% of Phase 3 trials in fact fail for reasons of approvability. This includes inadequate safety and efficacy for FDA approval, issues with PK/bioavailability, and so forth.
If anything the infographic highlights the importance of strategic clinical development during every phase of the trial, in order to avoid late phase pitfalls.