Biotech Values

[Summer2762]

I would like to see a statistics about this. However, a decent size trial powered 90% to show a 25-35% improvement at final should be powered at least 20% at interim assuming the interim is at 1/2 # of events and uses standard OBF under the exact assumptions used during trial design. So I say the probability of early unblinding at interim should be higher than this at least if you think original trial design assumptions are correct (or if you think the trial will be a success at the end).