Simulation

The main goal of Simulx is to perform simulations of clinical trials. In other words, it simulates a population of individuals, in one or several groups, using different scenarios. It gives the last step of the modeling&simulation workflow, after model building in Monolix for instance.

There are two tasks in the simulation tab: SIMULATION that generates outputs, and OUTCOMES & ENDPOINTS – a post-processing task – that uses the simulation outputs to calculate outcomes (one per individual) and endpoints (summary over all individuals of a group). In addition, running the tasks produces and immediate feedback thanks to the automatically generated RESULTS and PLOTS.


Simulations of clinical trials include:

  • Simulation scenario – Building a simulation scenario takes place in the dedicated section “Simulation” and includes selecting simulation elements, creating groups for comparison and choosing sampling options.
  • Outcomes and endpoints – Outcomes & Endpoints are below the “Simulations” section.  Outcomes represent a post-processing of the simulation outputs for each individual. Endpoints summarize the outcome values over all individuals, for each simulation group and for each replicate. It is a separate task, so it does not require re-running the entire simulation after a modification.
  • Results – Results are in a dedicated tab as copyable tables. They include individual and output values, outcome&endpoint analysis and statistical group comparison.
  • Plots – All simulation outputs, defined outcomes and endpoints are displayed on separate plots as individual outputs and distributions. In addition, plot settings, stratification options and charts preferences are available at hand in the right panel of the interface.

A screenshot of the Simulation tab with an typical example of s simulation of a population of individuals in two groups with different treatment.

Order of events

There are prioritization rules in place in case of various event types occurring at the same time. So, the order of row numbers in the data set is not important, and same is true for the order of administration and empty/reset macros in model files.

The sequence of events will always be the following:

  1. regressors are updated,
  2. reset done by EVID=3 or EVID=4 is performed,
  3. dose is administered,
  4. empty/reset done by macros is performed,
  5. observation is made.

The behavior is consistent between Monolix and Simulx.

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