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Analyze Time-to-Event Data Using Hazard Ratio Limits of Confidence Interval

AnalyzeTTEUsingHazardRatioLimitsOfCI.Rd

This function analyzes time-to-event data using a simplified design based on upper and lower confidence boundaries for hazard ratios (HR). It determines whether to make a "Go" or "No Go" decision by assessing the likelihood of the HR being below specified limits. Specifically, the function utilizes the coxph() model from the survival package to estimate the log hazard ratio and its standard error. The decision-making process is as follows:

  • If the upper limit (UL) of the confidence interval is below the Minimum Acceptable Value (MAV), a "Go" decision is made.

  • If the lower limit (LL) of the confidence interval is above the Target Value (TV), a "No Go" decision is made.

  • Otherwise, the analysis continues to the next look.

At the final analysis:

  • If UL < MAV, a "Go" decision is made.

  • Otherwise, a "No Go" decision is made.

HR and log HR are monotonically related. Since coxph() outputs results for log HR, the function uses the log HR scale for decision-making.

Usage

AnalyzeTTEUsingHazardRatioLimitsOfCI(
  SimData,
  DesignParam,
  LookInfo = NULL,
  UserParam = NULL
)

Arguments

SimData

Data frame consisting of data generated in the current simulation.

DesignParam

List of design and simulation parameters required to perform the analysis.

LookInfo

A list containing input parameters related to multiple looks. Users should access variables using their names, such as:

  • LookInfo$NumLooks: Integer representing the number of looks in the study.

  • LookInfo$CurrLookIndex: Integer representing the current index look, starting from 1.

  • LookInfo$CumEvents: Vector of cumulative number of events at each look.

  • LookInfo$RejType: Code representing rejection types, with possible values:

    • Efficacy Only:

      • 0: 1-Sided Efficacy Upper.

      • 2: 1-Sided Efficacy Lower.

    • Futility Only:

      • 1: 1-Sided Futility Upper.

      • 3: 1-Sided Futility Lower.

    • Efficacy and Futility:

      • 4: 1-Sided Efficacy Upper and Futility Lower.

      • 5: 1-Sided Efficacy Lower and Futility Upper.

UserParam

A list of user-defined parameters. Must contain the following named elements:

UserParam$dMAV

Numeric; specifies the Minimum Acceptable Value (MAV).

UserParam$dTV

Numeric; specifies the Target Value (TV).

UserParam$dConfLevel

Numeric (0,1); specifies the confidence level for the t.test() function.

Value

A list containing the following elements:

HazardRatio

A double representing the computed hazard ratio.

Decision

Required integer value indicating the decision made:

0

No boundary crossed (neither efficacy nor futility).

1

Lower efficacy boundary crossed.

2

Upper efficacy boundary crossed.

3

Futility boundary crossed.

4

Equivalence boundary crossed.

ErrorCode

Optional integer value:

0

No error.

> 0

Non-fatal error; current simulation is aborted but subsequent simulations continue.

< 0

Fatal error; no further simulations are attempted.