Deep shit [RSABE / ABEL]

posted by Mikalai  – Belarus, 2020-01-31 16:07  – Posting: # 21121
Views: 4,127

Dear Helmut

» Duno what you mean. Are you considering the sample size of a 2×2×2 crossover? The sample size of the 2-period 4-sequence full replicate is ~½ though the number of treatments / biosamples (driving the study cost) are essentially the same.
» CV (%) ABE.2x2x2 ABE.2x2x4 n.ABEL n.ABEL.Bonf n.ABEL.adj n.Molins
»     20        20        10     18          24         18       22
»     30        40        20     34          44         42       42
»     40        66        34     30          38         32       36
»     50        98        50     28          34         28       32
» Try the functions pa.ABE() and pa.scABE() of PowerTOST.

» The plots in the slide are all for ABEL. A comparison of ABE and the EMA’s (unadjusted) ABEL:
» [image]
» At 30% sample sizes are 40 and 34, at 40% 68 and 30.
» Hhm, not sure what you mean.

I just would like to say that it has no sense to conduct ABEL/RABE trials if the CV is assumed around 30% because, in order to control TIE, we have to increase the sample size to around that of usual ABE trials. It violates GCP principles in this case and invalidates the ABEL/RABE approach (subjects are subjected to unnecessary risks in the ABEL/RABE trials). And it very complicates the matter. Basically, when should we consider an ABEL/RABE trial?

Best regards

It also seems that when we wish to control TIE the sample size will be around 50 (worst scenario + dropout rate) in almost every case (usually little known about reference withindividual variability) of the ABEL/RABE. But I have rarely seen such trials.


Edit: Merged with a later (now deleted) post. You can edit your posts for 24 hours. [Helmut]

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