Bioequivalence and Bioavailability Forum

Hi John,

❝ […] 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.

❝ ??? My suspicion is the number of decimal places they used. The plasma-time data is 3 decimal places.

Reasonable assumption. It might well be that – despite concentrations in the report are given with three decimals – the CRO used results in full precision. That’s not uncommon if a CRO runs both the analytical and statistical part of the study or if analytical results are transfer to another site in electronic form (f**ing Excel or SAS transport format). Ask the CRO to repeat the evaluation with data rounded to three decimal places (as given in the report). If they don’t get your results, something is wrong.

BTW, data transfer should always be done to the same precision as given in the analytical report. Imagine a case where a study passes with data in full precision and fails with results given in the report. Yes, regulators sometimes (especially if the CI is borderline) recalculate studies. Will ring the bell. In Excel there is an option to export to a CSV-file with “Precision as displayed”. That’s the way to go if you want to avoid discrepancies.

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

Pharsight will be happy to read this.