Estimating Parameter That Satisfies Minimal Efficacy

Hello,

I have a working PK/PD model implemented in SimBiology that relates the kinetics of a drug to it's effect on the growth of a tumor. I'm looking to perform the following task. The goal is to compute the dose at which a minimal efficacy signal is attained. Specifically, I'm looking to estimate the dose at which, four weeks post drug application, the tumor volume is 80% of the volume that is attained when the tumor grows without any applied drug. In other words, the dose at which there is a 20% reduction in the maximum volume attained after four weeks. I was wondering if there is a way to do this using SimBiology? Many thanks for your time in advance.

[emjey]

There is certainly a smarter way of doing it but why don't you simply scan a dose amount range? Unless you need to do it for many subjects, it would give you what you want very quickly.

[Arthur Goldsipe]

I can think of a couple of other ways to do this. Are you interested in writing functions or scripts that you run at the command line, approaches that use the SimBiology Model Analyzer app, or both?

[mitpi_182]

Hello Arthur,

Many thanks for your reply. I'm interested in both. I'm a relatively new user to SimBiology so I've mainly been using the Model Analyzer App but I'm planning to slowly transition to using the command line.

Answer 1

[Arthur Goldsipe]

Here's a high-level description of how I'd do this in the Analyzer App:

1. Create and run a simulation program that determines the tumor volume at 4 weeks when there's no drug.
2. Manually create and import a data set that specifies the target tumor volume you're trying to estimate at 4 weeks.
3. Create and run a fit program that estimates the dose amount. Use the data set from the previous step as the data you're using for fitting. Configure the program to use a baseline dose that has a parameterized dose amount, which is the parameter that you're estimating.

My command line workflow would be similar, except I'd be able to automate the creation of the data set.

Let me know if you need more details on any of the above steps. And if you do, also let me know what version of MATLAB you're using.