Thank you for the suggestion. It seems this NAD approach only uses the mea=
n data and does not estimate inter-subject variability using the standard d=
My intention is to establish a population PK/PD model with appropriate esti=
mation of intersubject variability based on the mean and standard deviation=
data at each timepoint.
A major assumption is that we have good knowledge of the base structure of =
the model (e.g. biexponential), and won't run the risk mistaking 2 mono exp=
onential models for a biexponential model
Your help and discussions will be very much appreciated.
From: Rekic, Dinko [mailto:Dinko.Rekic_at_fda.hhs.gov]
Sent: Thursday, September 10, 2015 10:41 AM
To: Zhu, Penny
Subject: RE: [NMusers] Question of fitting population PK
model using summary statistics of data instead of raw data
See the link and text below.
Naive averaged data approach (NAD)
A model without BSV and BOV is fitted to the
mean data from all individuals.
-Specialized software not
-Does not distinguish between
BSV and WSV.
-Inappropriate means lead to
biased parameter estimates.
-May produce model distortion
i.e., 2 mono exponential equations averaged together can
yield a biexponential.
-Covariate modeling cannot be
Dinko Rekić, Ph.D., MSc(Pharm)
Division of Pharmacometrics
Office of Clinical Pharmacology
Office of Translational Science
Center for Drug Evaluation and Research
U.S. Food and Drug Administration
10903 New Hampshire Ave
Silver Spring, MD 20993
WO Bldg 51, Rm 3122
Office phone: (8)240 402-3785
"The contents of this message are mine personally and do not
necessarily reflect any position of the Government or the
Food and Drug Administration."
On Behalf Of Penny Zhu
Sent: Thursday, September 10, 2015 9:49 AM
Subject: [NMusers] Question of fitting population PK model
using summary statistics of data instead of raw data
Assuming the population PK or PD data are log-normally (or
normally) distributed, if you have the mean and standard
deviation of a readout at each timepoint but do not have the
actual raw data (assuming all pateints are with the same
dosing regimen, etc), is it possible to establish a
well fitted population PK or PD model? How would one
get about doing it?
Your help is very much appreciated
Received on Thu Sep 10 2015 - 14:06:47 EDT