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RE: Sampling and sample size for pkpd analysis

From: Martin Bergstrand <martin.bergstrand>
Date: Fri, 20 Feb 2015 10:13:27 +0000

Dear Bernard and all,

This is a few of the scientific papers on that topic that I am aware of:

Vong C, Bergstrand M, Nyberg J, Karlsson MO. Rapid sample size calculations=
 for a defined likelihood ratio test-based power in mixed-effects models. A=
APS J. 2012 Jun;14(2):176-86.

Ogungbenro, K., Aarons, L. & Graham, G. Sample size calculations based on g=
eneralized estimating equations for population pharmacokinetic experiments.=
 J. Biopharm. Stat. 16, 135-50 (2006).

Kang, D., Schwartz, J. B. & Verotta, D. Sample size computations for PK/PD =
population models. J. Pharmacokinet. Pharmacodyn. 32, 685-701 (2005).

Lee, P. Design and power of a population pharmacokinetic study. Pharm. Res.=
 18, 75-82 (2001).

For the practical implementation of sample size calculations you can use th=
e MCMP or the SSE functionality in PsN:

Best regards,

-----Original Message-----
From: owner-nmusers
 Behalf Of Bernard Ngara
Sent: den 17 februari 2015 17:39
To: nmusers
Subject: [NMusers] Sampling and sample size for pkpd analysis

Dear all

I would like to apply pkpd-vd analysis to quantify the impact of
HAART(based) prophylaxis to the rate of mother to child transimission and p=
rogression of HIV-1 in mother and child pairs expected to be followed up fo=
r a minimum of 2 years. Can you please assist me on the following issues:

1. What are the methods to use for determining the minimum number of mother=
 and newborn pairs to be included for pkpd-vd analysis?

2. What are the minimum number of blood samples and optimal sampling times =
should i collect from both mother and newborn pairs to obtain an accurate m=
easure of the drug and viral load levels over the 2-year period?

Primary covariates to be included in the analysis are CYP2B6, CYP3A4 and AB=

Your comments and suggestions are welcome.


PhD Student, University of Zimbabwe

Bernard Ngara
Trainee Biostatistician
Africa Institute of Biomedical Science and Technology P. O Box 2294 Harare =
+263 772 160 896
Received on Fri Feb 20 2015 - 05:13:27 EST

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