[R-pkgs] New package ‘bcrm’ to implement Bayesian continuous reassessment method designs

Michael Sweeting michael.sweeting at mrc-bsu.cam.ac.uk
Fri Jan 13 18:23:08 CET 2012

Dear R users,

I am pleased to announce  the release of a new packaged called `bcrm’ 
(version 0.1), now available on CRAN.

The package implements a wide range of Bayesian continuous reassessment 
method (CRM) designs to be used in Phase I dose-escalation trials. The 
package is fully documented and highlights include
•    A choice of 1-parameter working models or the 2-parameter logistic 
•    Bayesian updating performed after outcomes from each cohort of 
patients becomes available, using exact computation or MCMC methods (via 
either BRugs or R2WinBUGS).
•    Full functionality allowing a range prior distributions for the 
model parameter(s) as well as calculation of standardised doses from 
prior estimates of toxicity at each dose level
•    The ability to choose the summary estimate of the posterior 
distribution used to select the next dose (options are posterior mean or 
plug-in mean toxicity or a quantile of the maximum tolerated dose (MTD) 
distribution, as in an EWOC design).
•    Specification of a modified (constrained) or unmodified CRM design.
•    Varying the cohort size
•    Plots of the data and estimated dose-toxicity curve after each 
cohort has been recruited.
•    Fully integrated simulation code, which returns operating 
characteristics of the design as output. Alternatively, the user can 
interactively run the design, specifying doses and outcomes as each new 
cohort is recruited, as if conducting a trial.

In a future release I hope to allow full loss function based decisions 
to be made, using toxicity intervals (areas of the posterior distribution).

As this package is new I would appreciate any feedback users have.

Best wishes
Michael Sweeting

Dr Michael Sweeting
MRC Biostatistics Unit
Institute of Public Health
Robinson Way

Tel: 01223 768257
Fax: 01223 760729

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