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 OneArmTTE_GUI_V3.0.8.zip  1229 KB Windows installer and documentation
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One-Arm Time-to-Event Simulator

The One-Arm Time-to-Event Simulator (One-Arm TTE Simulator) is a user friendly implementation of the One-Arm Time-to-Event trial design.
The statistical method is based on the paper “Monitoring event times in early phase clinical trials: some practical issues” by Thall, Wooten and Tannir.

screen shot showing the Model Parameters tab page

NOTE: Information about specific versions is below.

The software was developed by John Aven, Clift Norris, and John Venier.  The software tools were: Microsoft Visual Studio 2015 (Update 3); C#; .Net Framework 4.6.1. (as of September, 2018)

System Requirements

  • Windows 7 SP1 (but may work on later versions of Windows as well, although this has not been tested)
  • Microsoft .NET Framework version 4.6.1 (x86 and x64)
  • Windows Installer 4.5
  • Minimum Screen Resolution 1235x850

If any required software component is absent from your system, the installation process will install it.

About Version 3.0.8

Version 3.0.8 adds the ability to switch off/on the stopping rule monitoring at patient accrual time. A dialog control for this was added to the GUI. This monitoring is performed during trial simulations.

Several minor bugs were fixed.

About Version 3.0.7

Version 3.0.7 adds changeable dimensional units for the Delta_U and Delta_L values at the bottom of the Model Parameters tab on the GUI. The units are the same as the Prior Distributions. In previous versions, the units were always "Days". Important note: Input files saved with versions 3.0.6 and earlier can be opened with v3.0.7, but a warning message will be displayed stating that the Delta_U and Delta_L values may be in error and should be verified on the GUI. You are urged to check these values.

The program can now check for software updates that are available from MD Anderson. An automatic check is performed when the program initially starts, and the user can manually check via the "Help.Check for updates" menu item.

About Version 3.0.6

Version 3.0.6 fixes a minor user interface input bug affecting users attempting to enter prior parameters for distributions with large means and small variances, as well as some enhancements to error handling and stability improvements.

About Version 3.0.5

Version 3.0.5 has an entirely rewritten simulator. In addition, trial duration is now estimated from the beginning of the simulated virtual patient accrual process, instead of the first virtual patient accrual. Thus this operating characteristic will be on average one virtual patient inter-arrival time longer compared with previous versions of One-Arm Time-to-Event Simulator. For example, if you have specified in a simulation scenario an accrual rate of 2.5 patients per month, the estimated trial duration will be on average slightly over 12 days longer for that scenario compared with previous versions of the software.

About Version 3.0.4

Version 3.0.4 has a much improved Recent Files system.

About Version 3.0.3

Version 3.0.3 fixes a bug preventing computers with a positive UTC offset from being able to run One-Arm Time-to-Event Simulator, updates the required .NET framework, and has many improvements.

About Version 3.0.2

Version 3.0.2 fixes a bug preventing users running One-Arm Time-to-Event Simulator on a computer through Remote Desktop from being able to save their work.

About Version 3.0.1

Version 3.0.1 contains improvements based on user feedback, and bug fixes.

Important note for version 3.0.0 users: Input files saved with version 3.0.0 can’t normally be opened with version 3.0.1. If you need help with this, please contact us.

About Version 3.0.0

  • Model Parameters:
    screen shot showing the Model Parameters tab page
    Model Parameters Tab
    • Prior Distributions:
      The method requires the specification of prior distributions for the Standard Treatment Arm and an Experimental Treatment Arm. The prior distributions are Inverse Gamma distributions.

      The prior distributions may be defined by specifying the Mean and Standard Deviation, the shape and scale, or two quantiles.

    • Mean or Median:
      The software supports parameterizing the Exponential Time-to-Event distributions in terms of the Mean TTE or the Median TTE.
    • Stopping Rules:
      Trials can be designed to Stop Early due either to superiority or inferiority (or both if desired). Also, the design will specify whether maximizing or minimizing the time-to-event is desirable.
    • Trial Monitoring:
      You can specify that the trial be monitored at periodic times (Periodic Monitoring) and after a Post-Accrual Follow-Up Period. These monitoring times are in addition to the monitoring which (optionally) occurs immediately before each patient is accrued.

      Specifying the minimum number of patients to be greater than one postpones any monitoring of the trial from occurring until at least the minimum number of patients has been accrued.

    • Time Units:
      Many of the parameters in the software have a time unit associated with them. These units can be set to be Days, Weeks or Months.
    • Help:
      Clicking on the blue or firebrick text in the form will open context-specific help in the window on the right hand side of the form.
  • Simulation Run:
    screen shot showing the Simulation Run tab page
    Simulation Run Tab
    • Scenarios:
      Scenarios are specified by providing a Name, True Mean/Median Time-to-Event, Accrual Rate, and Seed for the random number generator.

      The specified time units for True Mean/Median Time-to-Event and Accrual Rate will be used for all scenarios.

      Scenarios can be added, deleted, duplicated, and moved up and down the list.

    • Credible Interval Percentage:
      Some Operating Characteristics are reported with computed Sample Quantiles. These quantiles are computed using a Credible Interval Percentage as descriptive of a centralized Sample Quantiles range.

      For example, a Credible Interval Percentage of 95% will correspond to a Sample Quantiles range of ( 0.025 , 0.975 ).

    • Simulation Output:
      After the simulations have completed, or have been aborted, an HTML formatted report will be output to a window on the right hand side of the form. This will contain a many expandable regions: Model Parameters (Input), Summary Table, and an expandable region for each Scenario.
    • Help:
      Clicking on the blue or firebrick text in the form will open context-specific help in the window on the right hand side of the form.


  1. Peter F. Thall, Leiko H. Wooten, and Nizar M. Tannir (2005). Monitoring event times in early phase clinical trials: some practical issues. Clinical Trials, 2(6), 467-478.