How to Filter Data with Phoenix WinNonlin

How to Filter Data with Phoenix WinNonlin

Phoenix WinNonlin is Certara’s new implementation of the popular pharmacokinetic software that has been the mainstay of non-compartmental analysis for over 15 years. But, this newest version is the biggest change in the software since the original PC Nonlin was converted to the Windows-based “WinNonlin” (i.e. Windows Nonlin). In Phoenix WinNonlin, there are a powerful set of data manipulation tools that allow a user to standardize analyses and create re-usable objects.

In this post, I will demonstrate how to filter data using the powerful Data Wizard object. For this example, let’s assume we have completed a non-compartmental analysis, and now we want to create a subset of results that includes just a few of the PK parameters (Cmax, Tmax, and AUCall) for summarization. This is commonly done when completing an analysis to support a bioequivalence study. The Cmax and AUC are needed for statistical analysis, but all other PK parameters are only presented in a summary table. By creating a standard filter (like I demonstrate here), you can quickly add this filter object to any workflow where you need to subset your data.

Start by sending the non-pivoted Final results from the NCA Analysis to a Data Manager object. It is important to use the Final Results file rather than the pivoted Final results. The difference is that the Final results contain one record per line while the pivoted Final results contain all records for an individual subject. The Final results are much easier to use for programming purposes (like we are doing here).

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When the Data Wizard object appears, it will appear as shown below. There are three main areas: the summary in the upper left, the data in the upper right, and the operation details in the lower section. Since no operations have been selected, there will be no information in the upper right and lower sections.

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Now select “Filter” using the Action pull-down, then click the Add button. (See below)

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After the filter action is selected, options appear in the upper right and lower sections. The upper right section contains information about the data set. It lists the columns of data available. You can select the magnifying glass on paper icon in the upper section (circled in red) to preview the data set. Then in the lower section, select the “Custom” option button and click the “Add” button (both circled in red in the lower section).

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The “Custom” option allows you to write your own selection criteria for summarizing the data. It is particularly useful when you have more than one selection to make. In our case, we want to include 3 different values of the Parameters: Tmax, Cmax, and AUCall. If you only need to select a single value (i.e. only Cmax), you can use the “Built In” option, or if you only need to exclude a single value (i.e. exclude parameter estimates of “0”) you can use the “Selection Exclude” option. I personally prefer the Custom option as it is more flexible. After you select the Add button, a box will pop open and allow you to enter your custom code. Enter the information shown below to include only the Tmax, Cmax, and AUCall parameter estimates.

parameter estimates

This code allows you to use boolean logic (e.g. and, or) to make selections. In this case, we want to use “or” to include all cases when the Parameter column equals either Tmax OR Cmax OR AUCall. When you have completed the code shown above, click the OK button. Then click the “Execute Step” button in the lower section as shown below (circled in red). This will execute the filter procedure and produce a results dataset.

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By clicking on the results tab in the upper section, you can then view the results of your filter. The “Results” worksheet will include the results of the filter procedure. The “Step 1 Filter Filtered Results” worksheet will include all records excluded by the filter procedure. As shown here, a data set that included more than 15 parameters for each subject now only has the three parameters of interest. You can look at both the results and filtered results to make sure that the filter operated as expected.

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Now this results file can be used to calculate descriptive statistics, produce tables or figures, or conduct other statistical analyses. In addition, this Data Wizard object can be copied and pasted into other workflows and connected to an input data set to give the same results. That makes repeat analyses very simple. That is all there is to filtering data with Phoenix WinNonlin.

To learn about how we’ve improved Phoenix to make performing NCA and PK/PD modeling even easier, please watch this webinar I gave on the latest enhancements to Phoenix.

Nathan Teuscher

About the Author

Nathan Teuscher

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Dr. Nathan Teuscher is the Vice President of Pharmacometric Solutions at Certara. He is an expert in clinical pharmacology, pharmacometrics, pharmacokinetics and pharmacodynamics and was trained by David Smith at the University of Michigan. Dr. Teuscher has held leadership positions in biotechnology, pharmaceutical and contract research companies. In 2008 he established the Learn PKPD.com website to share his knowledge with the community. Prior to coming to Certara, he was the Founder and President of PK/PD Associates.