Re: sequential PK/PD
From: "Lewis B. Sheiner"
Subject: Re: [NMusers] sequential PK/PD
Date: Thu, 02 May 2002 10:44:05 -0700
I had hoped that Liping would clarify this more than she did.
As Mats discussed, there are a number of ways to do sequential vs
simultaneous fitting. Liping and I have been studying these,
following up on Mats' and Janet Wade's work.
The short answer is that Mat's method #3, whereby one fits the
PK data alone, then fits ALL the data to the PKPD model with all
pop PK parameters fixed to values obtained in the previous PK fit,
generally saves computation time relative to
the simultaneous method (Mats' #2), and produces results that
are just as good.
Mats' method #1, whereby one the fits PK data alone, generates Post-hoc
PK parameters, and uses these for the second step PD model fit using
only the PD data in the second step, saves more time, and is almost as
good. There is no point to including the PK data in the last step of
here since they will not influence the PD fit at all.
LBS.
--
_/ _/ _/_/ _/_/_/ _/_/_/ Lewis B Sheiner, MD (lewis@c255.ucsf.edu)
_/ _/ _/ _/_ _/_/ Professor: Lab. Med., Bioph. Sci., Med.
_/ _/ _/ _/ _/ Box 0626, UCSF, SF, CA, 94143-0626
_/_/ _/_/ _/_/_/ _/ 415-476-1965 (v), 415-476-2796 (fax)