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Dear all
how the blood withdrawal time points are decided in a
clinical Phase III study? how many time points are
considered to be good as per guideline?
Mr. Neel Kamal Mohan
Manipal
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Dear Neel
In phase III, the main stress is on determining efficacy. Generally the
PK part is dealt in phase I and to some extent in Phase II. Regarding
specific guidelines on how many time points to be selected in Phase
III, to my knowledge there is no such guideline. We generally take very
few time points in Phase III and then from this sparse data determine
patient characteristics, using population pharmacokinetics or
pharnmacodynamics. Hope this helps.
Regrds
Tausif Ahmed
Ranbaxy Research Laboratories
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Neel,
If you know your compound's PK, you have a good opportunity to plan
your few samples per patient in a Phase III study to give you the most
information. Best samples are taken when changes occur. Let's say you
have a compound given as a single iv bolus dose that follows a
2-compartment model. I would distribute the samples to be taken some
minutes after the dose, around the time the distribution phase is
completed and some time down the elimination phase. Personally, I would
push for these time-points to be approximate and not exact, in order to
cover a wider time-range. However, in my experience, asking people NOT
to follow an exact time could be difficult, as is the case when you ask
for the EXACT time :-).
Toufigh Gordi
[Something like optimal sampling as per ADAPT II - db]
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Please clarify when Traucated AUC are required for the bioequivalence
studies and is there requirements tahat the AUC can only be trucated at
72hrs . For some of the long half -life drugs having the Thalf of
70-72hrs
can Truncated at 72hrs for bioequvalence study.
Thanks
Manoj Kumar Vishwakarma
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If AUC extrapolate is greater than 20%, it is not possible to use the PK
data for BE.
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Copyright 1995-2010 David W. A. Bourne (david@boomer.org)