Lottery or science? [PK / PD]

posted by ElMaestro  – Denmark, 2015-01-13 12:05 (3770 d 05:09 ago) – Posting: # 14278
Views: 9,388

Hi Nobody,


❝ Yepp, it was bioequivalent. But is this a merrit of the formulation? Or was it purely by chance (if you have a look at the lower limit of the CI for Ctrough)? Or was it something else ;-)?


❝ Imagine that a slightly different trough value for ONE formulation in a SINGLE volunteer might have resulted in a lower limit of CI for Ctrough of 79.98%


I see your point, and yes I quite agree. Hope for the best, light some candles in the church, make sacrifices on your home altar to please the higher powers. You do not always have any other good options.
It is tremendously problematic when regulators tack on new CIs that also need to pass a criterion. Sometimes I think the inclusion of such "new" metrics seem intuitive but look to be quite without a scientific basis.
Perspective: In the Advair US guidance which was published 2013 FDA required 50 (fifty!!) succesful BE-tests, including 14 confidence intervals in order for the product to be considered bioequivalent.

In such situations when primary requirements are piled skyhigh, It is virtually impossible to plan your way out of it, unless you happen to
either
  1. have lot of $$$ so that you can power each individual test to something like 99.XYZ % so that the whole shebang passes with 80% chance or whatever your overall power aim is.
  2. have a tremendous insight on how the individual metrics correlate and can model your way out of the trouble. Noone really has this insight to an extent where the uncertainty in the model isn't a problem.

Pass or fail!
ElMaestro

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