MDL - The DDMoRe Modelling Description Language
Nick Holford (1), Mike Smith (2) on behalf of DDMoRe WP3 contributors
1. Department of Pharmaceutical Biosciences, Uppsala University, Sweden 2. Dept Statistical Pharmacometrics, Pfizer Global Research & Development, United Kingdom
Objectives: Definition of a modelling description language (MDL) is a key deliverable from the Innovative Medicines Initiative Drug Disease Modelling Resource (DDMoRe) project . The MDL aims to provide a new standard in describing pharmacometric models consistently across software tools and brings together features of various existing modelling languages. It is intended to be flexible, extensible, easy to code, understand and use. Together with the associated computer-readable markup language, PharmML, the aim is to facilitate automated translation of models and modelling tasks into target application scripts for NONMEM, Monolix, Phoenix NLME, BUGS, R and Matlab.
Methods: A DDMoRe work-package group comprising members from European universities, small to medium enterprises (SME) and the pharmaceutical industry have collaborated for 2 years to develop the MDL. A draft MDL description was proposed and refined through review and input from colleagues across the project. Example models (Use Cases) have been proposed which test the ability of the language to describe a variety model features succinctly and unambiguously.
Results: A MDL specification document has been written that describes the structure and properties of the language. There are two components 1) the Model Coding Language (MCL) which is declarative and describes the mathematical model, parameters, data and task properties. 2) the Task Execution Language which is procedural and defines the workflow of modelling tasks using a R like language which may include (but is not limited to) estimation, simulation, diagnostics, modelling summaries and data generation. Close integration with R is desirable to leverage existing and established modelling and simulation packages. Automated translation from NM-TRAN to MDL  and from MDL to NM-TRAN has been demonstrated for simple models. A "Rosetta Stone" has been constructed to assess whether key attributes within the target languages have been adequately expressed within the MCL and to identify how translation of MDL to the other target languages can be achieved.
Conclusions: It is expected that conversion to the remaining target application scripts will occur rapidly now that the feasibility of using NM-TRAN has been confirmed. Public release of the language specification will occur by June 2013. This work is presented on behalf of the DDMoRe project.
 The DDMoRe project, www.ddmore.eu Accessed 14 March 2013
 Holford NHG. nt2mdl - an automated NM-TRAN to MDL translator. http://nmtran-to-mdl.mango-solutions.com/ Accessed 14 March 2013