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Dear all,
I am a PKPD beginner and met some issues when I try to do PK/PD model of
a anticancer drug using WinNonlin 5.2. I wish you would help me or
give me some instructions:
1) how to do PK model serval dose levels simutaneously?
I tried to give a extra column in data file and gave different doses in
Model Parameter window. Does that mean they are modeled simutaneously?
If yes, however, the plot output for each dose level are in separate
sheet. Could you please tell me how to get the plots of separate doses
in the same plot?
2) If do PD model, different doses will obtain different Emax and EC50
values. How to avoid it and model simutaneously to get ONE set of PD
parameters for varied doses?
3) Does NDA regulatory accept the different PKPD model co-exsting for
one drug with varied dose levels?
Thank you very much!
Jenny L. Peng
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The following message was posted to: PharmPK
Jenny,
I'm just about to sign off for the night but I want to briefly touch on your questions;
Firstly, please take your free upgrade to Phoenix WinNonlin, the current version is
6.2.1, jusyt about everything you want to do is far easier in the new Phoenix Model Engine
with many examples given in the WinNOnlin and NLME guides to be found in the installation
folder; C:\Program Files (x86)\Pharsight\Phoenix621\docs (the latter is useful for more
detailed examples of writing you own models - even if you haven't got the NLME algorithms
licensed since they use the same model engine.
Regarding your questions, 1) is certainly possible, perhaps you could look around the
discussion forum for Phoenix; or post an example of the model and data you're using;
www.pharsight.com/extranet (also free), in addition to our Support desk.
Overlay plots of different doses are easy using the Predicted values worksheet and
appropriate Group variables, typically dose level as you described your data.
2 (&3?) If do PD model, different doses will obtain different Emax and EC50 values. How to
avoid it and model simultaneously to get ONE set of PD parameters for varied doses? Are
you sure your dose response is linear? it may not be and you will need to account for that
in the model.
We can also offer training; both public -
http://www.pharsight.com/training/training_upcoming.php or onsite, which can be
customised (or indeed consulting services) to help you understand your compound better.
Best regards,
Simon.
--
Simon.Davis.at.certara.com
Senior Scientific Consultant
Pharsight- A Certara(TM) Company
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You can add the doses on the dose tab in the setup section you do not need the samedose
to run
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Thank you very much for the suggestion.
I added as you suggested and obtained different final parameters and
output plots for varied doses. Is here any way to get the same set of
parameters and overlayed plots?
Thank you.
Jenny
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