randomEmax {clinDR}

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'))

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

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.

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.

Author(s)

Neal Thomas

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)