toxbdry {clinfun}R Documentation

Stopping rule for toxicity monitoring

Description

Computes a stopping rule and its operating characteristics for toxicity monitoring based repeated significance testing.

Usage

toxbdry(pLo, pHi, n, cP0=0.1, cP1=0.9, ngrid=6, niter=5,
          priority=c("null","alt"))
bdrycross.prob(n, r, ptox)
## S3 method for class 'toxbdry':
print(x, ...)

Arguments

pLo the toxicity rate that is acceptable.
pHi the toxicity rate that is too high and hence unacceptable.
n vector of times (sample size) when toxicty is moniroted.
r vector of maximum acceptable toxicities corresponding to n.
ptox the toxicity rates for which the operating characteristics are calculated.
cP0 boundary crossing probability under pLo i.e. type I error or the probability of declaring a treatment with toxicity rate pLo unacceptable.
cP1 boundary crossing probability under pHi i.e. power or the probability of declaring a treatment with toxicity rate pHi unacceptable.
ngrid the number of toxicity rates from pLo to pHi for which the operating characteristics are computed.
niter the number of iterations run to obtain the boundary.
priority the error threshold to prioritize when the max sample size is too small to have both error thresholds satisfied. Default is the null i.e. error under pLo.
x object returned by the function toxbdry.
... additional arguments to print.

Value

the function returns a list with:

looks when toxicty is monitored - same as input n.
lo.bdry lower boundary is a vector of maximum acceptable number of toxicities corresponding the number of subjects in n. The boundary crossing probability for this is slightly above cP0.
hi.bdry upper boundary is a vector of maximum acceptable number of toxicities corresponding the number of subjects in n. The boundary crossing probability for this is slightly below cP0.
bdry.oc the operating characteristics i.e the toxicity rate, the probability of crossing, stopping (i.e. cross before the last observation) and the expected sample size for both the low (lo) and high (hi) boundaries.
bdry.alpha the alpha levels for testing at each look for the two boundaries.


stopping for toxicity is done when the number of toxicities exceeda the boundary i.e. the boundary gives the maximum acceptable number.

Examples

  toxbdry(0.2, 0.35, c(20,40,60,75))
  toxbdry(0.2, 0.3, c(20,40,60,75), cP0=0.15, cP1=0.8)
  toxbdry(0.1, 0.3, 2:30) # continuous monitoring
  toxbdry(0.1, 0.3, 2:25, priority="alt") # prioritize cP1 error threshold

[Package clinfun version 0.8.4 Index]