ICON's nonlinear mixed effects modelling tool used in population pharmacokinetic/ pharmacodynamic analysis.


NONMEM® is a nonlinear mixed effects modelling tool used in population pharmacokinetic/pharmacodynamic analysis

The Software:

NONMEM® versions up through VI are the property of the Regents of the University of California, but ICON Development Solutions has exclusive rights to license their use. NONMEM® 7 up to the current version 7.2.0 is the property of ICON Development Solutions.

The software consists of three parts.

  • The NONMEM® program itself is a very general (non-interactive) model analysis program that can be used to fit models to many different types of data. With version 7, Monte Carlo expectation-maximization and Markov Chain Monte Carlo Bayesian methods have been added to the classical likelihood methods available in previous versions. NONMEM® can be used to simulate data as well as fit data. 
  • PREDPP is a powerful package of subroutines that can be used by NONMEM® to compute predictions for population pharmacokinetic and pharmacodynamic data. Use of PREDPP obviates the need for the user to code kinetic-type equations and it also allows complicated patient-type data to be easily used. However, the user can also directly and very generally code prediction-type, likelihood or -2 log-likelihood equations, and thus a great variety of different types of models can be used. 
  • NM-TRAN is (non-interactive) preprocessor, allowing control and other needed inputs to NONMEM/PREDPP to be specified in a user friendly manner, with quick and comprehensive detection of a variety of errors that the user may have made in so doing.

NONMEM® 7 is programmed in Fortran 90/95 code and can be used with 32 or 64 bit Windows, Linux, Macintosh OSX, or Solaris operating systems incorporating a Fortran 90/95-compliant compiler. Since some NONMEM® runs can take considerable time, perhaps many hours or even days, depending on the speed of the computer and the size of the problem, it is advisable to use a fast machine with at least 1.0 Gb of available memory. For multiprocessor and multi-core environments 3-4 Gb of memory may be needed to accommodate several simultaneous NONMEM® runs.

NONMEM® 7.2 includes the following enhancements:

  • Exact likelihood maximization methods, such as importance sampling expectation maximization (EM), and stochastic approximation EM. 
  • Full three stage hierarchical Markov Chain Monte Carlo (MCMC) methods. 
  • Parallel computing of a single problem over multiple cores or computers, significantly reducing completion time.  
  • Dynamic memory allocation according to problem size, eliminating the need to recompile the NONMEM® program for unusually large problems. User may override program generated suggested values using a statement in the control stream. 
  • Improved incidence of success in problems using the first-order conditional estimation method. 
  • Improved incidence of completion when using the “Super Problem” feature. 
  • Additional result files, with number of significant digits selectable by the user, and which can be easily read by post-processing programs. 
  • Control stream files may be written in mixed case
  • Initial parameter entries in the control stream file may be of any numerical format. 
  • Numbers of data items per data record increased to a default maximum of 50, which can be increased if needed. 
  • Label names may be as large as 20 characters. 
  • Added flexibility in the input and output of variance matrix parameters
  • XML markup version of the NONMEM® report file
  • Features to facilitate stochastic differential equations (SDE).

The NONMEM program is available on CD ROM, which together with the documentation and all updates and additions to the program and documentation, will be delivered for a license royalty fee to be paid annually. This fee is subject to change from year to year, and at each anniversary the licensee at its option may choose not to renew the license.