PMXFrem

The goal of PMXFrem is to provide pre- and post-processing support for Full Random Effects Models (FREM) built in NONMEM. It facilitates the conversion of FREM models to Full Fixed Effects Models (FFEM), enabling standard project workflows including Goodness-of-Fit (GOF) diagnostics, Visual Predictive Checks (VPC), and forest-plot based results communication.

Installation

You can install the development version of PMXFrem from GitHub with:

# install.packages("devtools")
devtools::install_github("pharmetheus/PMXFrem")

The vignette sources are in vignettes/. Open the .Rmd files in RStudio and click Knit to compile, or run browseVignettes("PMXFrem") to read the versions built at install time.

To get the latest stable release (including vignettes), download the source package from the releases page of the GitHub repository: the file whose name starts with PMXFrem and ends in .tar.gz. Install it with the install.packages command, e.g.:

install.packages("path_to_release.tar.gz", repos = NULL, type = "source")

If your organizational SOPs require installation via an internal package manager (e.g., Posit Package Manager) or a localized server, please prioritize those methods over GitHub to ensure environment stability and reproducibility.

Further information

A FREM analysis has more moving parts than a short example can usefully show, so the documentation takes it a piece at a time. PMXFrem assembles FREM data sets, converts a converged FREM model to its FFEM counterpart, extends an established model with new structural thetas and IIVs, derives subject-specific variances for missing covariates, and produces the parameter tables, diagnostics, forest plots and explained-variability plots a FREM analysis is reported with. The vignettes are written to be read in order:

1. Quick Start - a 5-minute copy-pasteable example to verify your installation and run a basic FREM-to-FFEM conversion.
2. The Walk-Through - the full workflow, from data assembly to forest plot generation.
3. The deep dives - one vignette per topic, for the parts of the workflow that need more than the walk-through gives them.

Once the package is installed you can issue the command: browseVignettes("PMXFrem")