[NMusers] Major public release of nlmixr

From: Wang, Wenping <wenping.wang_at_novartis.com>
Date: Fri, 13 Oct 2017 21:40:48 +0000

The nlmixr team is very proud to announce a major public release of nlmixr,=
 an open source package for population PK and PKPD modelling. nlmixr builds=
 on the RxODE package for simulation of nonlinear mixed effect models using=
 ordinary differential equations, by implementing parameter estimation algo=
rithms like nlme and SAEM (with gnlmm and FOCEi under active development). =
nlmixr greatly expands the utility of existing packages (like nlme) by prov=
iding an efficient and versatile way to specify pharmacometric models and d=
osing scenarios, with rapid execution due to compilation to C++.

This new release features a unified user-interface. This user-interface pr=
ovides PKPD modelers a minimalist, intuitive, expressive, domain-specific m=
odeling language to compactly describe the model structure & efficiently ex=
plore the population data at hand. Below is an example of specifying the t=
heophline data by this domain language:

f <- function(){
             lCl <- -3 # log Cl (L/hr)
             lVc <- -1 # log Vc (L)
             lKA <- 1 # log Ka (1/hr)
             add.err <- c(0, 0.2, 1)
             eta.Cl ~ 0.1 # BSV Cl
             eta.Vc ~ 0.1 # BSV Vc
             eta.KA ~ 0.1 # BSV Ka
             ## First parameters are defined in terms of the initial estima=
             ## parameter names.
             Cl <- exp(lCl + eta.Cl)
             Vc <- exp(lVc + eta.Vc)
             KA <- exp(lKA + eta.KA)
             ## Next, the differential equations are defined
             d/dt(depot) = -KA*depot;
             d/dt(centr) = KA*depot-Cl/Vc*centr;
             ## And the concentration is then calculated
             cp = centr / Vc;
             ## Last, nlmixr is told that the plasma concentration follows
             ## an additive error (estimated by the parameter prop.err)
             cp ~ add(add.err)

fit <- nlmixr(f, theo_sd, est="saem")

On Tuesday, 17 October, 2017, 7:30-9:30 am, Rik Schoemaker will present an =
nlmixr poster at ACoP (T-012): nlmixr: an open-source package for pharmacom=
etric modelling in R. Get in touch, see us at ACoP to discuss ways you coul=
d contribute (Matt Fidler, Rik Schoemaker, Yuan Xiong, Justin Wilkins, Mirj=
am Trame and Wenping Wang will all be there), or try it out for yourself, a=
nd experience the joy of a population modelling package within R! The sourc=
e is available at https://github.com/nlmixrdevelopment/nlmixr<https://urlde=
IRVD2gUNA4p0Ii_Dc8A-4vGp5GzGqpFA8c&e=>, and the nlmixr team is in the pro=
cess of submitting the package to CRAN, and working hard to further improve=
 this community based modeling tool. Our goal: Express your model in nlmixr=
, openly and freely.

Wenping Wang, PhD
Executive Director, Pharmacometrics
Novartis Pharmaceuticals Corporation
One Health Plaza, East Hanover, NJ 07936-1080, USA
Phone +1 862 7789009; Fax +1 9737818265

Received on Fri Oct 13 2017 - 17:40:48 EDT

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