Bioequivalence and Bioavailability Forum

Dear Mike,

❝ ... Since the study will be carried out in patients and due to budget

❝ limits, we only expect to be able to include around 12 subjects ...

Whatever your final chosen statistical test method for your problem is (superiority t-test of treatment groups Bonferroni corrected, Dunnett test of treatment groups with supplement versus treatment with drug alone, regression analysis of AUC vs. 'dose' of supplement ...), I bet one of my monthly salary^*) that the power you calculate based on your chosen statistical test is low if sample size is 12, given your mentioned intra-subject CV of greater then 30%.

What does this imply for you ?
Would you abandon your study because power is low?
Or would / can you wait for a sponsor coming around next time with some million bucks in his long pocket to allow you to recruit enough patients to attain a higher power?

Or would you go for it to investigate your question nevertheless? Because its so of interest or potential benefit for patients that it is worth to investigate even with low power, low sample size.

One may argue that it is unethical to do such a study with low number of subjects. For that I recommend Stephen Senn's book
"Statistical issues in drug development"
Wiley 2007
Chapter 13.2.7

Let me cite:
"The argument here is that one should not ask patients to enter a clinical trial unless one has a reasonable chance of finding something useful. Hence small or ‘inadequately powered’ trials are unethical.
There is something in this argument. I do not agree, however, that small trials are uninterpretable and, as was explained in Section 13.2.2, sometimes only a small trial can be run. It can be argued that if a treatment will be lost anyway if the trial is not run, then it should be run, even if it is only capable of ‘proving’ efficacy where the treatment effect is considerable ...
... As Edwards et al. have argued eloquently, some evidence is better than none.".
(Emphasis by me)

^*)BTW: You can't become rich because of that .