build_gs_norm: Build a multi-stage group-sequential multi-arm clinical trial...

In mjg211/multiarm: Design of single- and multi-stage multi-arm clinical trials

Build a multi-stage group-sequential multi-arm clinical trial for a normally distributed primary outcome

Description

build_gs_norm() builds a multi-stage group-sequential multi-arm clinical trial design object assuming the primary outcome variable is normally distributed, like those returned by des_gs_norm.

Usage

build_gs_norm(
  n10 = 77,
  n1 = n10 * (1 + K * ratio),
  e = c(2.42, 2.42),
  f = c(-2.42, 2.42),
  K = 2,
  alpha = 0.025,
  beta = 0.1,
  delta1 = 0.5,
  delta0 = 0,
  sigma = 1,
  ratio = 1,
  power = "marginal",
  stopping = "simultaneous",
  type = "variable",
  spacing = (1:length(e))/length(e),
  summary = FALSE
)

Arguments

n10	A numeric indicating the chosen value for n10, the sample size required in the control arm in stage one of the trial. Defaults to 54.
n1	A numeric indicating the chosen value for n1, the total sample size required in stage one of the trial. Defaults to n10\*(1 + K\*ratio).
e	A numeric vector indicating the chosen value for e, the efficacy (upper) stopping boundaries. Defaults to c(2.42, 2.42).
f	A numeric vector indicating the chosen value for f, the futility (lower) stopping boundaries. Defaults to c(-2.42, 2.42).
K	A numeric indicating the chosen value for K, the (initial) number of experimental treatment arms. Defaults to 2.
alpha	A numeric indicating the chosen value for α, the significance level (family-wise error-rate). Defaults to 0.025.
beta	A numeric indicating the chosen value for β, used in the definition of the desired power. Defaults to 0.1.
delta1	A numeric indicating the chosen value for δ1, the 'interesting' treatment effect. Defaults to 0.5.
delta0	A numeric indicating the chosen value for δ0, the 'uninteresting' treatment effect. Defaults to 0.
sigma	A numeric vector indicating the chosen values for σ0 and σ1, the standard deviations of the responses in the control and experimental arms. Must be of length 1 or 2. If of length 1, it is assumed that σ0 =σ1. Defaults to 1.
ratio	A numeric indicating the chosen value for r, the stage-wise allocation ratio to present experimental arms. Defaults to 1.
power	A character string indicating the chosen type of power to design the trial for. Can be "disjunctive" or "marginal". Defaults to "marginal".
stopping	A character string indicating the chosen type of stopping rule. Can be "separate" or "simultaneous". Defaults to "simultaneous".
type	A character string indicating the choice for the stage-wise sample size. Can be "variable" or "fixed". Defaults to "variable".
spacing	A numeric vector indicating the chosen spacing of the interim analyses in terms of the proportion of the maximal possible sample size. It must contain strictly increasing values, with final element equal to 1. Defaults to (1:length(e))/length(e) (i.e., to equally spaced analyses).
summary	A logical variable indicating whether a summary of the function's progress should be printed to the console. Defaults to FALSE.

Value

A list, with additional class "multiarm_des_gs_norm", containing the following elements:

• A tibble in the slot $opchar summarising the operating characteristics of the identified design.

• A tibble in the slot $pmf_N summarising the probability mass function of the random required sample size under key scenarios.

• A numeric in the slot $maxN specifying max N, the trial's maximum required sample size.

• A numeric in the slot $n_factor, for internal use in other functions.

• Each of the input variables.

See Also

des_gs_norm, gui, opchar_gs_norm, plot.multiarm_des_gs_norm, sim_gs_norm.

Examples

# The design for the default parameters
des <- build_gs_norm()

mjg211/multiarm documentation built on Jan. 19, 2024, 8:21 a.m.