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Dear All,
We are going to conduct clinical study of three strengths of the
drug. During PK and Statistical analysis, we would like to calculate
dose proportionality.
Can somebody throw a light on this point?
Thanks in advance.
Thanks with Regards,
Prakash Patel
Project Manager
Veeda Clinical Research Pvt. Ltd.
Shivalik Plaza - A
Near IIM, Ambavadi
Ahmedabad 380015, India
website: www.veedacr.com
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The following message was posted to: PharmPK
Dear Prakesh (and responders to questionnaire),
A questionnaire on methods used to assess dose proportionality was
recently
posted on the PharmPK website. The questionnaire asked whether dose
normalisation or power model (Gough et al. Drug Information Journal
1995;
29:1039 1048) was used and whether beta (derived from power moel) was
estimated with confidence intervals. In addition, if a power model
was used,
under what circumstances dose proportionality was concluded; i.e.
close to
one, CI includes unity or within prescribed limits based on Smith's
criterion (Smith: In Pharmacokinetics in Drug Development: Clinical
Study
Design and Analysis, Volume 1, Bonate P., Howard D eds., 363-382. AAPS
Press, USA, 2004).
Of the 11 responders (6 pharmaceutical companies, 3 CROs and 2
independent
consultants), 9 estimated an exponent from the power model with
confidence
intervals. Of these 9 responders, 5 claimed dose proportionality if the
exponent included unity, 3 have used the approach recommended by
Smith and 1
concluded dose proportionality if the exponent was close to unity.
Thus, testing of the hypothesis that beta=1 was the most common
approach;
however, this was not proposed by Gough et al., and Senn [Statistical
issues
in drug development. Wiley: Chichester, 1997; pp 291 313] emphasised
that
"it will presumably not be adequate simply to test the null
hypothesis that
\0x03B2 is equal to one".
Charlie Brindley
Ray French
Jurgen Hummel
Sue McKendrick
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