Confidence intervals vs. point estimators [Regulatives / Guidelines]

posted by Dr_Dan  – Germany, 2010-08-06 11:55 (4865 d 16:49 ago) – Posting: # 5727
Views: 14,891

Dear Helmut
I would prefer if you could change the category back to statistics in order to to proceed in discussion, because I do not think that speculations about regulatory affairs aspects would help solving my problem. To get into discussion with the assessor I really need some strong arguments.

Dear all

I am not an expert in statistics but as far as I know the 90% confidence interval for Cmax and AUC tells one that the true test/reference ratio lies within this interval with a probability of 90%. On the one side we will argue that for both primary bioequivalence parameters there is a overlapping of confidence intervals for all four studies. On the other side the assessor will argue that the point estimators of the second pilot study are not included by the confidence intervals of the other studies -> batch variability! Is this reasonable?

As Pavidus explained BE studies are definitely not suitable to assess inter-batch variability of any product. Which arguments can support this idea? To my understanding the only possibility to detect batch variability of the test product would be to perform a three way cross-over study with test 1, test 2 and reference). If you get different point estimators for your test batches (they can not be exactly the same) how far can they differ in order to claim similarity? Beside this nobody raised the question if the results we obtained are due to batch differences of the orginator.

Your input is very much appreciated.
Kind regards

Category changed back. [Helmut]

Kind regards and have a nice day

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