Bioequivalence and Bioavailability Forum

Dear All,

I have been tracking the forum for last two years and found so many answers to my question, however, I believe there hasn't yet been a discussion regarding the following topic.

I am dealing with vasoconstriction assay as a BE method of topical corticosteroids.
I have an ointment and cream (same active ingredient) and according to "relatively old" FDA guideline for vasoconstriction assay I would have to perform pilot and pivotal study for each, ointment and cream (i.e. 4 studies).

I would like to optimize this with increasing number of application sites on each arm (i.e. more than proposed by FDA: 6/arm for pilot and 10/arm for pivotal) and using one arm for ointment and other for the cream. This would mean: same number of subject, but only two studies.

I have considered:
- literature data show that there is no difference between left and right arm

I am wondering :
- What is the highest number of application sites that I can have on each arm?
- Would the increased amount of product (due to increase in # of application sites) administered to each subject lead to any safety concerns?

Do you have any experience/arguments to support or to object with this kind of design?

Thank you for any feedback.

Best Regards

d_krajc

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Edit: URLs for the interested reader: FDA’ guidance (1995) and EMA’s Q&A (2006). [Helmut]