Dear nmusers,
I am planning to analyze categorical PD data from rats in order to make
predictions for an effective concentration in humans. As I have never
analyzed this type of data, I was hoping to get some help from some of the
more experienced modellers.
I have PK data available after intravenous drug administration as well as
after administration of four different oral or s.c. doses, respectively,
from some animals but not all. The PK can be described with a
two-compartment model. Concerning the PD data, I have three different
categories: no response, partial response, full response, available for
both the oral as well as the s.c. route. Thus, the PD data looks like
this:
PD category
dose (mg/kg) full response (%) partial response (%) no
response (%)
0.5 0 0 100
0.75 17 0 83
1 33 17 50
1.5 50 50 0
The percent value means how many animals of the whole group show the
respective response.
My question is if it is possible to obtain a pharmacodynamic parameter
such as an IC50 value from this type of data or if the information is
insufficient. If that is the case, what kind of information can I get from
this type of data? Any suggestions, including NONMEM control streams and
information about the dataset creation (anything special there?) would be
highly appreciated. One equestion that came to my mind was also whether it
would be possible to treat one category as continuous in the sense that
clearly, with higher concentrations, a lot more animals showed the full
response? If it is possible, how would I implement this?
Thanks and best wishes
Nele
_________________________
Dr. Nele Plock
Bayer Schering Pharma AG
Drug Metabolism & Pharmacokinetics
Development Pharmacokinetics
Scientific Expert Development Pharmacokinetics
D- 13342 Berlin
Phone : +49-30-468 15146
Fax: +49-30-468 95146
[EMAIL PROTECTED]
http://www.bayerscheringpharma.de
Vorstand: Arthur J. Higgins, Vorsitzender | Werner Baumann, Andreas Busch,
Ulrich Köstlin, Kemal Malik, Gunnar Riemann
Vorsitzender des Aufsichtsrats: Werner Wenning
Sitz der Gesellschaft: Berlin | Eintragung: Amtsgericht Charlottenburg 93
HRB 283
