sim3p3: Simulate 3+3 design

In raredd/desmon2: More tools for the design and monitoring of clinical trials

Simulate 3+3 design

Description

Simulate a standard 3+3 dose (de-)escalation study.

Usage

sim3p3(probs, expansion = 10, escalation = TRUE, n.max = Inf)

Arguments

probs	vector of true rates of DLTs
expansion	(optional) integer giving size of expansion cohort
escalation	logical; if TRUE, dose-escalation rules are used; otherwise, de-escalation rules are used with decreasing probs
n.max	maximum number of patients available for dose-finding and expansion cohorts combined

Value

A list with the following components:

$data	dose by patient matrix: 0 - no DLT, 1 - DLT
$summary	total number of DTLs, patients, and probability of DLT per dose level for escalation and total
$level	mtd level (i.e., row of data selected)
$mtd	DLT rate of dose level selected
$expansion	observed rate of DLT in expansion cohort
$cohort	observed rate of DLT in all patients
$enrolled	total number of patients enrolled on study

See Also

simcrm

Examples

## standard 3+3 with 10 patient expansion cohort
pr <- 1:5 / 10
sim3p3(pr)


## run 1000 3+3 studies
sim1 <- replicate(1000L, sim3p3(pr), simplify = FALSE)

op <- par(mfrow = c(1, 2), las = 1L)
out <- sapply(sim1, function(x) c(x$level, x$enrolled))
barplot(
  prop.table(table(out[1, ])),
  main = 'Dose selected',
  xlab = 'RP2D',
  ylab = 'Proportion selected'
)
boxplot(
  split(out[2, ], out[1, ]),
  ylim = c(0, length(pr) * 6 + 10),
  main = 'N used to select dose x',
  xlab = 'Dose selected\n(0 - no safe dose)',
  ylab = 'Total size'
)
par(op)


## 3+3 de-escalation, starting at highest dose
## run 1000 3+3 studies
pr2 <- rev(pr)
sim2 <- replicate(1000L, sim3p3(pr2, escalation = FALSE), simplify = FALSE)

op <- par(mfrow = c(1, 2), las = 1L)
out <- sapply(sim2, function(x) c(x$level, x$enrolled))
barplot(
  prop.table(table(out[1, ])),
  main = 'Dose selected',
  xlab = 'RP2D',
  ylab = 'Proportion selected'
)
boxplot(
  split(out[2, ], out[1, ]),
  ylim = c(0, length(pr) * 6 + 10),
  main = 'N used to select dose x',
  xlab = 'Dose selected\n(0 - no safe dose)',
  ylab = 'Total size'
)
par(op)

raredd/desmon2 documentation built on April 13, 2025, 1:56 a.m.