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Re: [NMusers] Generating TAD with ADDL dosing format

From: Bill Denney <wdenney_at_humanpredictions.com>
Date: Tue, 20 Dec 2016 07:39:54 -0500

Hi Camila,

It sounds like you've got two questions here-- one related to NONMEM and
one related to the other program you're using to create your VPC. The
NONMEM question appears to be "How do I get TAD in my data without
changing my dataset?" The second question appears to be "How to I
stratify my VPC based on that new TAD variable instead of TIME?"

For the second question, what program are you using for VPC?

For the first question, others may have a more elegant answer, but I
think that you're right: ADDL makes many dose-related events
difficult. The simplest answer is to revise your dataset adding a TAD
column. If you can't do that, then something like this will work
assuming that you only have one dosing record per subject. (Note that
the code below was typed directly into email, so it may have typos.)

; Set TAD to -1 before any dose record for the subject

IF (NEWIND.EQ.2) THEN
   DOSETIME = -1
   ADDLREC = 0
   IIREC = 0
ENDIF
; Capture the (most recent) dosing information for this subject
IF (EVID.EQ.1 .OR. EVID.EQ.4) THEN
   DOSETIME = TIME
   ADDLREC = ADDL
   IIREC = II
ENDIF
; Calculate TAD from the single dose record for a subject in the data
set assuming
; that there is only one dose record per subject or that the dose
records occur
; such that the most recent dose record is the only one important for
calculating
; TAD for a subject. This assumption would not hold if there is a dose
record
; with ADDL that has a dose record for a time in the middle of those
ADDL doses.
IF (DOSETIME.LT.0) THEN
   ; This subject has not received a dose yet, set TAD to -1
   TAD = -1
ELSEIF ((TIME-DOSETIME) .LE. ((ADDLREC+1)*IIREC)) THEN
   ; This subject is in the middle of the ADDL records for this dose,
   ; calculate time since most recent dose.
   TAD = (TIME-DOSETIME) - INT((TIME-DOSETIME)/IIREC)*IIREC
ELSE
   ; This subject is are after the last ADDL dose, calculate time since
the final
   ; dose (observed so far).
   TAD = (TIME-DOSETIME) - ((ADDLREC+1)*IIREC)
ENDIF

Thanks,

Bill


On 12/20/2016 6:45 AM, de Almeida, Camila wrote:
>
> Hello,
>
> I was wondering if I could get some guidance from this great group. My
> issue is primarily with some diagnostic analysis, but this is taking
> me back to an old NONMEM problem.
>
> My aim is to run a VPC on a model I implemented, and if possible
> change the idv to TAD instead of TIME. The reason for that is the VPC
> graph based on TIME looks dreadful as the data is sparse and from
> different studies of different lengths.
>
> Iím having issues generating the TAD output column from my NONMEM run.
> I naively assumed I could easily do that, but looking at the NONMEM
> archives it seems this gets tricky when your dosing events are written
> using ADDL. Has anyone ever managed to find a solution for this? And
> if not, is there an alternative way to run the VCP on TAD, do we
> really need to get this column from NONMEMís output?
>
> Thanks all,
>
> *Camila de Almeida, PhD*
>
> PKPD Scientist,
>
> *Modelling & Simulation, IMED Oncology DMPK*
>
> *________________________________________________________________________________*
>
> *AstraZeneca UK Limited*
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> *R&D, Innovative Medicines*
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------------------------------------------------------------------------
Human Predictions Logo <http://www.humanpredictions.com>*William S.
Denney, PhD*
Chief Scientist, Human Predictions LLC
+1-617-899-8123
wdenney_at_humanpredictions.com

Received on Tue Dec 20 2016 - 07:39:54 EST

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