Dear list
Using Stata 8.1
I'm unsure on how to calculate the required sample for the following trial,
been searching by findit for equivalence ado's without finding my answer:
We are planning to do a 2 year equivalence trial.The current standard of
treatment has a 2 year failure rate of 7%: In our trial of a new drug, the
treatments will be considered equivalent if the 95% confidence interval are
within the bound of -12% to 12%, which we believe is the the largest
difference that would be considered clinically acceptable.
First off, it would seem that what is appropriate here is a non-inferiority
setup (1-sided) rather than (bio)equivalence (2-sided). If the new drug is
much much better, that's good and acceptable, no? Why would you want to
bound the efficacy difference from both sides? It's only when the new drug
is worse that you might need to impose bounds. It comes down to what
exactly you want to prove:
