NONMEM Users Network Archive

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Model building

From: Indranil Bhattacharya <ibhattacharya>
Date: Thu, 3 Dec 2009 10:40:32 -0500

Hi, I am in the process of developing a PK/PD model and have a naive
question regarding model building.
I currently do not have all the PD data and more data would be available in
the future. For the current data set, I have tried models say A to D.
Now model A (cell kill) and B (cell kill +transduction) converges using
FOCE (no CV% but I am willing to live with that) but from the RES and WRES
plots we can clearly see that there is some bias. The fit is OK but not
great. The ofv values are around 400.
Now models B (cell cycle specific kill), C (cell + precursor cell kill
+transduction) and D (cell cycle specific + indirect response model) do not
converge using FO or FOCE methods but when I look at the fits from the
terminated runs, the fits are much better than those obtained with Model A,
and there seems very little bias. Also the ofv values are between 160-250.

So my question is whether the fits, RES, WRES plots and the ofv values have
meaning even when the minimization terminates.



Indranil Bhattacharya

Received on Thu Dec 03 2009 - 10:40:32 EST

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