The
wikipedia
article on drug trial phases which indicates sizes and groups
types is an interesting starter on clinical trials, and there are some links to approval and success rates.
This
is a table of clinical trial approval rates at each stage:
Stage of Development Probability of Approval
- Phase 1
9%
- Phase 2
15%
- Phase 3 44%
- Submission 80%
So basically only 9% of candidate drugs make it through the phase 1
trial, so there is massive attrition. my rudimentary calculations
make that if you start with 1000 phase 1 trials then 90 make it to
phase 2, of those 13.5 make it to phase 3, and then .44 of those.
Hence only ~6 make it to the application for approval to the FDA
(this is US data, but its broadly similar over here)
