The Changing Landscape for Human Absorption, Metabolism, and Excretion: Practical Experiences From a Data Analysis of 500 Studies.

Coincidental with the intensified regulatory and industry focus on the design and conduct of human absorption, metabolism, and excretion (hAME) studies in the past 12 months, we have recently completed our 500th cohort involving radiolabeled test item administration to humans. Here, we build upon a recent industry white paper in this journal1 and share some of our own experiences as a Contract Research Organization based upon collaborations with numerous pharma companies and their differing approaches to design and timing, to add further context to the discussion regarding hAME studies and the pivotal role that drug metabolism and pharmacokinetics plays. In this article, we explore how both changing relationships within the industry and shifting regulatory guidelines are impacting strategies, and compare EU and US pre-study approval requirements, before evaluating the trends from over 500 studies conducted at our global facilities conducted over more than 30 years. We conclude with a review of how improved technical capabilities and strategies are influencing the design and conduct of hAME studies, before speculating on some of the driving factors which may shape the direction they take in the future.

One small step in time, one giant leap for DMPK kind - a CRO perspective of the evolving core discipline of drug development.

As the Space Race or Formula 1 drives innovation, efficiency and progress in home technology and home car markets, Drug Metabolism and Pharmacokinetics (DMPK) drives scientific innovation and value for drug development companies. Stand still and fall behind as the saying goes, and these analogies are true as much in the design and conduct of DMPK studies as they are in the technology and manufacturing sectors.This short review showcases the impact that DMPK has had on drug development and how it has changed in the last 10 years, illustrating the value added scientific benefit, cost and time saving, that innovative DMPK program design and study conduct have. Examples and case studies spanning novel in vitro alternatives such as organ-on-a-chip (OOAC) developments; use of in vivo microsampling across small and large animal species; challenging historical paradigms in Absorption, Distribution, Metabolism and Excretion (ADME) studies; and embracing new technologies to address regulatory concerns, are presented.The continual pace of change has kept DMPK at the core of pharmaceutical, crop and chemical evaluation, and this is set to continue as regulators use this discipline to inform decision-making. With new modalities and new scientific questions, DMPK will continue to evolve, with the likes of new in vitro, in vivo and in silico models becoming central to candidate selection and progression.

Minipig and Human Metabolism of Aldehyde Oxidase Substrates: In Vitro-In Vivo Comparisons.

The importance of aldehyde oxidase (AOX) is becoming increasingly recognized in the prediction of human pharmacokinetic parameters from animal data. The objectives of these studies were to ascertain whether an in vitro-in vivo correlation existed in the clearance and metabolic pathways of AOX substrates and to establish whether the minipig represented an appropriate non-rodent model for man in the pre-clinical development of drugs metabolized by AOX. Using the AOX substrates carbazeran, 6-deoxypenciclovir and zaleplon, clearance was estimated from in vitro depletion experiments with minipig and human liver cytosol and microsomes and scaled before comparison with data generated in parallel in vivo studies in minipigs. In vitro and in vivo metabolic pathways were characterized by LC-MS/MS. Scaling of in vitro metabolism data to predict in vivo clearance underestimated in vivo values, although the rank order of clearance for the three compounds was preserved. Prediction of human in vivo clearance from scaled minipig in vivo data produced results which correlated well with published clinical values. Overall, this study is the first to compare minipig in vitro metabolism data with in vivo pharmacokinetic data for compounds metabolized by AOX and provides a scientific rationale for the selection of this species as a model for humans in the development of drugs which are substrates of AOX.