Hi Shen,
The short answer is yes, under $PK you could fit a linear spline through the
observed conc. and use it in $DES.
Ex.
$PK
IF(NEWIND.NE.2) THEN
LCP=0
LTM=TIME
ENDIF
INT = LCP
TINT = LTM
DEN = TIME-TINT
IF(DEN.EQ.0) THEN
SLOP = 0
ELSE
SLOP = (CP-INT)/DEN
ENDIF
LCP=CP
LTM=TIME
$DES
INPUT=INT+SLOP*(T-TINT) ;INPUT IS INTERPOLATED CP
Best,
Nidal
Nidal AL-Huniti, PhD
Associate Director, Modeling and Simulations
ICON Development Solutions SM
On 4/3/09, Shen Li <[email protected]> wrote:
>
> Dear all,
>
> Can an indirect response model be used for PD modeling alone in NONMEM
> (without PK modeling)? I am planning to evaluate the concentration-response
> relationship for a PD marker. I am wondering whether I can just use the
> observed PK concentrations in the indirect response model in NONMEM.
>
> Thanks!
> Shen
>
