clinDR (version 2.4.1)

randomEmax: Random data constructor function for emaxsim(B) creating random parameters for an Emax model for continuous or binary data.

Description

Creates a list object that contains inputs and a function to create simulated data sets for emaxsim(B). Data sets are created by generating random parameters from an emaxPrior.control() object for a 3/4 parameter Emax model. For binary data, the Emax model is on the logit scale and then back-transformed.

Usage

randomEmax(x,n,doselev,modType=c('4','3'))

Value

A list of length 2. The first element is itself a list named genP that contains named elments n, doselev, dose, modType and the emaxPrior object x. The second element is a function named genFun that takes genP as input and returns a list with named elements meanlev, parm, resSD, y.

Arguments

x

Object of type emaxPrior created by function emaxPrior.control, that specifies a prior distribution for the Emax model parameters.

n

Sample size for each dose group.

doselev

Dose levels (including 0 for placebo) included in the study corresponding to n. Must be in increasing order.

modType

Specifies a 4-parameter sigmoidal Emax model, or a 3-parameter hyperbolic Emax model

Author

Neal Thomas

Details

Normal data are generated from the dose response curves with homogeneous-variance normal residuals. Binary data are 0/1 generated from Bernoulli distributions with proportions computed by transforming the Emax model output from the logit to proportion scale. Default values are based on recommendations in the references.

References

Thomas, N., Sweeney, K., and Somayaji, V. (2014). Meta-analysis of clinical dose response in a large drug development portfolio, Statistics in Biopharmaceutical Research, Vol. 6, No.4, 302-317. <doi:10.1080/19466315.2014.924876>

Thomas, N., and Roy, D. (2016). Analysis of clinical dose-response in small-molecule drug development: 2009-2014. Statistics in Biopharmaceutical Research, Vol. 6, No.4, 302-317 <doi:10.1080/19466315.2016.1256229>

Wu, J., Banerjee, A., Jin, B. Menon, M. S., Martin, S. and Heatherington, A. (2017). Clinical dose response for a broad set of biological products: A model-based meta-analysis. Statistical Methods in Medical Research. <doi:10.1177/0962280216684528>

See Also

emaxsimB, emaxsim, FixedMean

Examples

prior<-emaxPrior.control(epmu=0,epsca=4,
	difTargetmu=0,difTargetsca=4,dTarget=20,
	p50=(2+5)/2,
	sigmalow=0.01,sigmaup=3)
						
simParm<-randomEmax(x=prior,n=c(99,95,98,94,98,98),
	doselev=c(0,5,10,25,50,150),modType="4")
		
# D1 <- emaxsimB(nsim=10,simParm,prior,nproc=1)