Bioequivalence and Bioavailability Forum

Hi Helmut and others,

❝ With the correct coding I never saw different results from SAS and PHX. Is this a hypothetical example or from the ‘real world’? On the other hand different results in higher-order Xovers are possible (again independent from software)...

Here is a strange one I just experience. 100% final plasma data from a 3-way (2 formulation vs reference) study. Both myself and the CRO used SAS Proc GLM to compute A vs C, B vs C (alpha=0.05 yes). Results? My lower 90% CI for formulation 1 was 80.24, CRO result showed 79.65 at the lower limit of the 90% CI. I checked my individual parameter values with theirs and they all matched! Okay their report only show 2 decimal places and I use 4 decimals. The values are in tenths (? I mean numbers like 20.50, etc, not into hundredths). The difference in arithmetic means are like .5 for some reason.

Geometric (least square) means are also off
Mines are 31.82 (T), 35.50 (R), Intra CV = 24.44
Theirs are 31.8 (T), 35.55 (R), Intrasub CV = 25.8

??? My suspicion is the number of decimal places they used. The plasma-time data is 3 decimal places. No time deviation (0-24 hrs sampling, all in house)

John

P.S. I tried running WinNonlin and the output confirmed my numbers as well.