gsDesign 3.6.0

Time-to-event endpoint design with calendar timing of analyses

We added a gsSurvCalendar() function to enable group sequential design for time-to-event outcomes using calendar specification of interim analysis timing. These designs can use either information- or calendar-based spending with latter focused on trials where the priority may be on finishing in a fixed time rather than a fixed number of endpoints.

Integer sample size and event count

toInteger(): Fixed the documentation and execution based on the ratio argument.

print.gsSurv(): Improve the display of targeted events (very minor). The boundary crossing probability computations did not change. The need for this was made evident by the addition of the toInteger() function.

Translate survival design bounds to exact binomial bounds

toBinomialExact() and gsBinomialExact(): fixed error checking in bound computations, improved documentation and error messages.

Breaking change: gsSurv() and nSurv() have updated default values for T and minfup so that function calls with no arguments will run. Legacy code with T or minfup not explicitly specified could break; this was considered unlikely to be common and the new defaults offer some convenience.

Other improvements

These vignettes were updated:

• Vaccine efficacy trial design.
• Poisson mixture model.
• Integer sample size and event counts.

We added an as_rtf() method for gsBinomialExact objects, enabling RTF table outputs for standard word processing software.

For more details about the updates in gsDesign 3.6.0, see the changelog.

Integer sample size and event count

The app now defaults to translating group sequential design to integer events (survival designs) or sample size (other designs except information-based designs).

To change this behavior:

1. Click Global Options in the upper-right corner.
2. Switch off Enable integer sample size and event counts.
3. Click Save Settings.

The value of this new option will be saved when you save the design to the .rds file. For reproducibility, restoring previously saved designs will have this option switched off by default.

Calendar-based timing and spending

New options have been added to allow calendar-based timing and spending when creating the design.

Calendar-based timing:

1. Under the Design page, switch to the Timing tab.
2. In Timing type, select Calendar-based.
3. Fill out the Calendar timing increments.

Calendar-based spending:

1. Under the Design page, switch to the Boundaries tab.
2. In Spending type, select Calendar-based.

Note that these options will only show up when the endpoint type is time-to-event, and when the option under Enrollment is Vary enrollment rate (Lachin-Foulkes).

UI and report template improvements

We improved many theming details of specific UI elements in this release. For example, the Restore Design button now renders properly under Firefox. The padding of code blocks has been increased. The editing experience of matrix inputs is now better aligned with numeric or select inputs.

Last but not least, the R Markdown report templates now load ggplot2 explicitly. This is due to the dependency being moved from Depends to Imports since gsDesign 3.4.0 (#56).