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Concepts and Synonymy in the UMLS Metathesaurus

G. H. Merrill

Abstract: This paper advances a detailed exploration of the complex relationships among terms, concepts, and synonymy in the UMLS Metathesaurus, and proposes the study and understanding of the Metathesaurus from a model-theoretic perspective. Initial sections provide the background and motivation for such an approach, and a careful informal treatment of these notions is offered as a context and basis for the formal analysis. What emerges from this is a set of puzzles and confusions in the Metathesaurus and its literature pertaining to synonymy and its relation to terms and concepts. A model theory for a segment of the Metathesaurus is then constructed, and its adequacy relative to the informal treatment is demonstrated. Finally, it is shown how this approach clarifies and addresses the puzzles educed from the informal discussion, and how the model-theoretic perspective may be employed to evaluate some fundamental criticisms of the Metathesaurus.

Use a Predictive Approach to the ICH Q8 Definition of Design Space – CBI’s Annual Pharmaceutical technology Conference

John J. Peterson

An observational error model to investigate discordance in oncology studies with progression-free survival

Frank Mannino, Ohad Amit

Discussion of the convergence of best intention adaptive designs in dose-finding experiments

Yuehui Wu, Valerii Fedorov

Statistical power consideration of dichotomizing continuous outcomes

Val Fedorov, Chi-Hse Teng, Frank Mannino, Yuehui Wu

Dose reduction profiles for combination drug studies

John Peterson

Interim enrollment adjustment

Val Fedorov & Frank Mannino

The use of regression models in adjustment of treatment assignment

V. Fedorov

Modelling of multicenter trials: recruitment and drug supply

Vladimir Anisimov

Abstract: Patient recruitment and drug supply planning are the biggest challenges for clinical study design. The innovative statistical technique for modeling patient recruitment in multicentre clinical trials is proposed. It allows predicting recruitment with confidence boundaries at initial and ongoing stage of the study, evaluating study/centre performance and the minimal number of centres needed to complete recruitment in time with a given confidence, providing adaptive adjustment. Predicting in time the recruitment profile provides the opportunity to evaluate drug supply needed to cover patient demand for a given risk of patient stock out and establishes the basis for a novel approach in optimizing drug supply planning. The developed in R software tools use derived closed-form expressions, no Monte Carlo simulation involved. Technique is validated on real data, case studies are considered. The results are illustrated for several case studies.

Central versus investigator review for progression-free survival – an overview

Frank Mannino & Ohad Amit