titecrm {titecrm}R Documentation

TITE-CRM

Description

Returns an object of class mtd that summarizes the dose assignments and recommends a dose for the next patient in a phase I trial using TITE-CRM.

Usage

titecrm(prior, target, tox, level, n=length(level), weights=NULL, 
followup=NULL, obswin=NULL, scheme="linear", dosename=NULL, include=1:n, 
pid=1:n, method="bayes", scale=sqrt(1.34), model.detail=TRUE, 
patient.detail=TRUE)

Arguments

prior A vector of initial estimates of toxicity probabilities associated the doses.
target The target DLT rate.
tox A vector of patient outcomes; 1 indicates a toxicity, 0 otherwise.
level A vector of dose levels assigned to patients. The length of level must be equal to that of tox.
weights A vector of weights assigned to observations. A weight must be between 0 and 1. If given, the arguments followup, obswin, and scheme will be ignored. If not supplied, users must provide followup and obswin. The length of weights must be equal to that of tox.
n The number of enrollments.
followup A vector of follow-up times of patients. If not supplied, users must provide weights.
obswin The observation window with respect to which the MTD is defined. If not supplied, users must provide weights.
scheme A character string to specify the method for assigning weights. Default is ``linear''. Adaptive weight using Kaplan-Meier ``KM'' is to be made available.
dosename A vector containing the names of the regimens/doses used. The length of dosename must be equal to that of prior.
include A subset of patients included in the dose calculation.
pid Patient ID provided in the study. Its length must be equal to that of level.
method A character string to specify the method for parameter estimation. The default method ``bayes'' estimates the model parameter by the posterior mean. Estimation using ``mle'' is to be made available.
scale Standard deviation of the normal prior of the model parameter. Default is sqrt(1.34).
model.detail If TRUE, the model content of an ``mtd'' object will be displayed in detail.
patient.detail If TRUE, patient summary will be given in detail.

Details

Dose-toxicity relationship is assumed as an empiric power model $a_i^{exp(β)}$ where $a_i$ is the initial estimate of toxicity probability of dose level i and the model parameter $β$ has a normal prior with mean 0 and scale to be provided by users.

Value

An object of class ``mtd'' is returned, consisting of the summary of dose assignments thus far and the recommendation of dose for the next patient.

prior Initial estimates of toxicity probabilities.
ptox Updated estimates of toxicity probabilities.
target The target probability of toxicity at the MTD.
recommend The recommended dose level for the next patient.
scale The standard deviation of the normal prior.
estimate Estimate of the model parameter.
level Dose levels assigned to patients.
tox Patients' toxicity indications.
followup Follow-up times of patients.
obswin Observation window with respect to which the MTD is defined.
weights Weights assigned to patients.
scheme Weighting scheme.

References

Cheung, Y. K. and Chappell, R. (2000). Sequential designs for phase I clinical trials with late-onset toxicities. Biometrics 56:1177-1182.

Examples

# Create a simple data set
prior <- c(0.05,0.10,0.20,0.35,0.50,0.70)
target <- 0.2
level <- c(3,4,4,3,3,4,3,2,2,2)
y <- c(0,0,1,0,0,1,1,0,0,0)
u <- c(1,1,0.8,1,1,0.6,0.45,0.25,1/6,1/12)
tau <- 1
foo <- titecrm(prior,target,y,level,followup=u,obswin=1)
rec <- foo$recommend  # recommend a dose level for next patient

[Package titecrm version 0.1-1 Index]