From: Penny Zhu <*penny.zhu*>

Date: Thu, 10 Sep 2015 11:06:47 -0700

Dear Dinko

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=

eviation data.

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.

Penny

-----Original Message-----

From: Rekic, Dinko [mailto:Dinko.Rekic

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.

http://accp1.org/pharmacometrics/theory_popmeth.htm#npd

Naive averaged data approach (NAD)

A model without BSV and BOV is fitted to the

mean data from all individuals.

Features

-Specialized software not

necessary.

Disadvantages

-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

performed.

Kind regards

Dinko

_________________________________

Dinko Rekić, Ph.D., MSc(Pharm)

Pharmacometrics reviewer

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."

-----Original Message-----

From: owner-nmusers

[mailto:owner-nmusers

On Behalf Of Penny Zhu

Sent: Thursday, September 10, 2015 9:49 AM

To: nmusers

Subject: [NMusers] Question of fitting population PK model

using summary statistics of data instead of raw data

Dear all

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

Penny

Received on Thu Sep 10 2015 - 14:06:47 EDT

Date: Thu, 10 Sep 2015 11:06:47 -0700

Dear Dinko

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=

eviation data.

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.

Penny

-----Original Message-----

From: Rekic, Dinko [mailto:Dinko.Rekic

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.

http://accp1.org/pharmacometrics/theory_popmeth.htm#npd

Naive averaged data approach (NAD)

A model without BSV and BOV is fitted to the

mean data from all individuals.

Features

-Specialized software not

necessary.

Disadvantages

-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

performed.

Kind regards

Dinko

_________________________________

Dinko Rekić, Ph.D., MSc(Pharm)

Pharmacometrics reviewer

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."

-----Original Message-----

From: owner-nmusers

[mailto:owner-nmusers

On Behalf Of Penny Zhu

Sent: Thursday, September 10, 2015 9:49 AM

To: nmusers

Subject: [NMusers] Question of fitting population PK model

using summary statistics of data instead of raw data

Dear all

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

Penny

Received on Thu Sep 10 2015 - 14:06:47 EDT