Description Details Author(s) References See Also Examples
This package contains R-functions to perform power calculation in a group sequential clinical trial with censored survival data and possibly unequal patient allocation between treatment and control groups. The functions can also be used to determine the study duration in a clinical trial with censored survival data as the sum of the accrual duration, which determines the sample size in a traditional sense, and the follow-up duration, which more or less controls the number of events to be observed. This package also contains R functions and methods to display the computed results.
Package: | CR |
Type: | Package |
Version: | 1.0 |
Date: | 2012-06-18 |
License: | GPL-2 |
Depends: | methods |
Emil A. Cornea, Bahjat F. Qaqish, and Joseph G. Ibrahim
Maintainer: Emil A. Cornea <ecornea@live.unc.edu>
Ewell, M. and Ibrahim, J.G. (1997). The Large Sample Distribution of the Weighted Log Rank Statistic Under General Local Alternatives. Lifetime Data Analysis,3, 5-12.
Kim, K. (1992). Study Duration for Group Sequential Clinical Trials with Censored Survival Data Adjusting for Stratification.Statistics in Medicine, Vol. 11, 1477-1788.
Harrington, D. P. and Fleming, T. R. (1982). A class of rank test procedures for censored survival data. Biometrika 69, 553-566.
Gray, R.J. and Tsiatis, A.A. (1989). A linear rank test for use when the main interest is in differences in cure rates. Biometrics 45, 899-904.
curerate
, CureRate-class
,
showcr
, and show-methods
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 | ## Input Data
###############
# rho - specifies the value of rho in the G-rho test (Harrington and Fleming, 1982).
# rho = 0 gives the logrank test, and rho = 1 the Peto-Peto Wilcoxon test
#(and rho = -1 the test discussed by Gray and Tsiatis, 1989).
rho = 0
numreps = 500
##cureobs - probability of cure on the observation arm of the study
cureobs = .359
##curerx - probability of cure on the treatment arm of the study
curerx = .459
##medobs - median survival among the non-cured on observation
medobs = .747
##medrx - median survival among the non-cured on treatment
medrx = .859
##acrate - rate at which patients accrue, combined over both
##observation and treatment arms of the study
acrate = 232
##probrx - probability of assignment to the treatment arm
probrx = .5
##actime - accrual duration
actime = c(3.3, 3.5, 3.8);
##futime - follow-up duration
futime = c(2.0, 2.5)
##info - vector of information times for the interim looks
##must be an increasing sequence in (0,1]
info = c( .35, .61, .86, 1.0)
##crits - vector of critical values corresponding to the
##interim analysis time points specified in info
crits = c(3.6128, 2.6506, 2.1894, 2.0536)
#############################################################
### Log-rank test: rho=0 (default)
mycr<-curerate(rho,numreps,cureobs,curerx,medobs,medrx,acrate,
probrx,actime,futime,info,crits)
mycr ### (*)
show(mycr) ### same as above
showcr(mycr) ### same as above
showcr(mycr,full.result=TRUE)
showcr(mycr,indac=2,indfu=1)
showcr(mycr,indac=2:3,indfu=2:1)
showcr(mycr,indac=c(1,3),indfu=2)
show(mycr) ### same as (*) above
showcr(mycr) ### same as above
mycr ### same as above
### Peto & Peto modification of the Gehan-Wilcoxon test: rho=1
rho=1
mycr<-curerate(rho,numreps,cureobs,curerx,medobs,medrx,acrate,
probrx,actime,futime,info,crits)
mycr
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