Considerations for assessing the potential effects of antidiabetes drugs on cardiac ventricular repolarization: A report from the Cardiac Safety Research Consortium.

Thorough QT studies conducted according to the International Council on Harmonisation E14 guideline are required for new nonantiarrhythmic drugs to assess the potential to prolong ventricular repolarization. Special considerations may be needed for conducting such studies with antidiabetes drugs as changes in blood glucose and other physiologic parameters affected by antidiabetes drugs may prolong the QT interval and thus confound QT/corrected QT assessments. This review discusses potential mechanisms for QT/corrected QT interval prolongation with antidiabetes drugs and offers practical considerations for assessing antidiabetes drugs in thorough QT studies. This article represents collaborative discussions among key stakeholders from academia, industry, and regulatory agencies participating in the Cardiac Safety Research Consortium. It does not represent regulatory policy.

Effects of isoflurane, ketamine-xylazine and a combination of medetomidine, midazolam and fentanyl on physiological variables continuously measured by telemetry in Wistar rats.

BACKGROUND: This study investigated effects on cardiovascular parameters during anaesthesia with isoflurane (ISO, 2-3 Vol%), ketamine-xylazine (KX, 100 mg•kg(-1) + 5 mg•kg(-1)) or a combination of medetomidine-midazolam-fentanyl (MMF, 0.15 mg•kg(-1) + 2.0 mg•kg(-1) + 0.005 mg•kg(-1)) in rats throughout induction, maintenance and recovery from anaesthesia. Rats were instrumented with a telemetric system for the measurement of systolic, diastolic and mean arterial pressure (SAP, DAP, MAP), pulse pressure (PP), heart rate (HR) and core body temperature (BT). The parameters were continuously measured before, during and after each type of anaesthesia. Forty minutes after induction, ISO delivery was terminated and MMF was antagonized with atipamezole-flumazenil-naloxone (AFN, 0.75 mg•kg(-1) + 0.2 mg•kg(-1) + 0.12 mg•kg(-1)) whereas KX was not antagonized. RESULTS: Differences were observed between anaesthesias with KX (301 min) lasting much longer than MMF (45 min) and ISO (43 min). HR in ISO ([Formula: see text] = 404 ± 25 bpm) increased during the time of surgical tolerance whereas a HR decrease was observed in KX ([Formula: see text] = 255 ± 26 bpm) and MMF ([Formula: see text] = 209 ± 24 bpm). In ISO (MAP during time of surgical tolerance: [Formula: see text] = 89 ± 12.3 mmHg) and KX (MAP during wake-up period: [Formula: see text] = 84 ± 8.5 mmHg) mild hypotensive values were observed, whereas blood pressure (BP) in MMF (MAP during time of surgical tolerance: [Formula: see text] = 138 ± 9.9 mmHg) increased. Despite keeping animals on a warming pad, a loss of BT of about 1°C was seen in all groups. Additionally, we observed a peaked increase of HR ([Formula: see text] = 445 ± 20 bpm) during the wake-up period with ISO and an increase of PP ([Formula: see text] = 59 ± 8.5 mmHg) in MMF during the time of surgical tolerance. CONCLUSION: The anaesthesias influenced very differently the cardiovascular parameters measured in Wistar rats. ISO caused mild hypotension and increased HR whereas MMF produced a marked hypertension and a significant decrease of HR. The slightest alterations of BP, HR and BT were observed using KX, but the long wake-up and recovery period suggest the need for prolonged monitoring.

Influence of repeated anaesthesia on physiological parameters in male Wistar rats: a telemetric study about isoflurane, ketamine-xylazine and a combination of medetomidine, midazolam and fentanyl.

BACKGROUND: This study evaluated the influence of repeated anaesthesia using isoflurane (ISO, 2-3 Vol%), ketamine-xylazine (KX, 100 mg·kg(-1) + 5 mg·kg(-1), i.m.) or a combination of medetomidine-midazolam-fentanyl (MMF, 0.15 mg·kg(-1) + 2.0 mg·kg(-1) + 0.005 mg·kg(-1), i.m.) on heart rate (HR), arterial blood pressure (BP), body temperature (BT), duration of anaesthetic intervals and body weight (BW) in Wistar rats. Rats were instrumented with a telemetric system for the measurement of systolic, diastolic and mean arterial pressure (SAP, DAP, MAP), pulse pressure (PP), HR and BT during induction, maintenance and recovery of anaesthesia. Each anaesthesia was performed six times within three weeks. KX was not antagonized, but ISO delivery was terminated 40 minutes after induction and MMF was reversed with atipamezole-flumazenil-naloxone (AFN, 0.75 mg·kg(-1) + 0.2 mg·kg(-1) + 0.12 mg·kg(-1), s.c.). RESULTS: With repeated anaesthesia, ISO showed a decrease of HR and BP. A significant decrease of PP could be observed with repeated anaesthesia using MMF. HR and BP were not affected by repeated KX anaesthesia, but we noted a reduction of sleeping time and BW. Neither MMF nor ISO showed significant differences in the duration of anaesthetic intervals and BW. With KX we observed tissue necrosis at the injection site and surgical tolerance was not achieved in 25% of the anaesthesias performed. CONCLUSION: HR, BP values, BT, duration of anaesthetic intervals and BW were affected differently by repeated anaesthesia performed with ISO, KX or MMF. ISO produced a reproducible anaesthesia, thereby being suitable for repeated use, but with a decrease of HR and BP throughout the six anaesthesias. The use of ISO in cases where these parameters should be unaffected is therefore not advised. The inability to produce a surgical tolerance, the reduction of sleeping time and BW, as well as the tissue necrosis are significant contraindications for a repeated use of KX. Only mild changes of BP were found with repeated MMF anaesthesia, so it seems suitable for serial use, unless the high BP and the low HR during the surgical plane of anaesthesia are undesirable for a special procedure.

The impact of environmental and biological factors on the resting heart rate of dogs as assessed using 20 years of data from safety pharmacology studies.

INTRODUCTION: A safety pharmacology study detects and evaluates potential side effects of a new drug on physiological function at therapeutic levels and above and, in most cases, prior to the initiation of clinical trials. The aim of this study was to investigate the effects of environmental and biological factors on resting heart rate (HR), a representative cardiac parameter in cardiovascular safety pharmacology. METHODS: Over twenty years, 143 dogs (Beagles, Labradors and mongrels) received implanted telemetry transmitters to measure aortic pressure (AP), left ventricular pressure (LVP), Electrocardiogram (ECG) and body temperature. Throughout the 7-h period of data collection, data were continuously recorded without drug treatment and included the range of HRs resulting from spontaneous physiological changes. Statistics and visualizations were calculated using R and Spotfire. RESULTS: Beagles had a higher HR than the mongrels, while Labradors had a lower HR than mongrels. Labradors were found to have a sex-based difference in HR, with females having a higher HR. A higher HR was observed in young animals of all breeds when they were in contact with humans. The cage system affected the HR of Labradors and mongrels more than Beagles. Larger dogs (e.g. Labrador) have a lower HR than smaller dogs (Beagles). Animals that are younger were found to have more HR variability and have a higher HR than older animals. In addition, older animals reacted less to the application period and human interaction than younger animals. The HR response of animals inside a cage system may depend on the cage system in which they were bred. A familiar cage system typically has less impact on HR. DISCUSSION: This retrospective data base evaluation has demonstrated the impact of environmental and biological factors on cardiovascular parameters in the context of performing safety pharmacology studies. Breed, sex, age and the type of cage system used affected, at least in some cases, the HR and its variability. They should therefore be carefully considered when designing safety pharmacology studies to have the highest possible test sensitivity.

Optimization of bioanalysis of dried blood samples.

INTRODUCTION: Pharmacokinetic/pharmacodynamic modelling has emerged as a valuable technique for understanding drug exposure and response relationships in drug development. Pharmacokinetic data are often obtained by taking multiple blood samples, which may disturb physiological parameters and complicate study designs. Wearable automatic blood sampling systems can improve this limitation by collecting dried blood samples at programmable time points without disrupting cardiovascular parameters. It is the objective of this study to evaluate the bioanalysis of DBS in comparison to conventional blood sampling techniques and to optimize the recovery of various compounds spiked into canine blood dried on filter paper tape. METHODS: Incubated blood samples from Beagle dogs were spiked with 16 different compounds and half of the whole blood sample was centrifuged to obtain plasma. After the dried blood sample drops were dried, liquid chromatography-mass spectrometry methods were used to analyze the samples. The study explored different anticoagulants, sample preparation methods and technical approaches to best determine the compound concentrations in dried blood samples. RESULTS: With the two anticoagulants tested and using the optimized sample preparation methods and technical approaches we employed, the bioanalysis of dried blood samples can provide equivalent results to conventional blood sampling techniques. DISCUSSION: Automated blood sampling systems have the potential to provide increased numbers of blood samples, providing substantially more Pharmacokinetic data within safety pharmacology studies without disrupting physiological parameters. They can provide a viable alternative to traditional methods of obtaining blood for various other types of studies or analyses.

Thirty years of telemetry-based data acquisition for cardiovascular drug safety evaluation: Applications and optimization.

Conducting safety evaluations of new drugs using conscious animals has been a specialty of our working group for thirty years. In this article, we review the various technical challenges and solutions dealt with over the years to improve both the data quality and the well being of our animal subjects. Of particular interest for us has been the use of telemetry-based data acquisition for conducting studies on cardiovascular (CV) function. This includes the evolving technical aspects of the studies, as well as the development of new applications that take advantage of this technical approach.

Cardiovascular function in nonclinical drug safety assessment: current issues and opportunities.

There are several recent examples where clinically significant, safety-related, drug effects on hemodynamics or cardiac function were not apparent until large clinical trials were completed or the drugs entered the consumer market. Such late-stage safety issues can have significant impact on patient health and consumer confidence, as well as ramifications for the regulatory, pharmaceutical, and financial communities. This manuscript provides recommendations that evolved from a 2009 HESI workshop on the need for improved translation of nonclinical cardiovascular effects to the clinical arena. The authors conclude that expanded and improved efforts to perform sensitive yet specific evaluations of functional cardiovascular parameters in nonclinical studies will allow pharmaceutical companies to identify suspect drugs early in the discovery and development process while allowing promising drugs to proceed into clinical development.

Time for a Fully Integrated Nonclinical-Clinical Risk Assessment to Streamline QT Prolongation Liability Determinations: A Pharma Industry Perspective.

Defining an appropriate and efficient assessment of drug-induced corrected QT interval (QTc) prolongation (a surrogate marker of torsades de pointes arrhythmia) remains a concern of drug developers and regulators worldwide. In use for over 15 years, the nonclinical International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH) S7B and clinical ICH E14 guidances describe three core assays (S7B: in vitro hERG current & in vivo QTc studies; E14: thorough QT study) that are used to assess the potential of drugs to cause delayed ventricular repolarization. Incorporating these assays during nonclinical or human testing of novel compounds has led to a low prevalence of QTc-prolonging drugs in clinical trials and no new drugs having been removed from the marketplace due to unexpected QTc prolongation. Despite this success, nonclinical evaluations of delayed repolarization still minimally influence ICH E14-based strategies for assessing clinical QTc prolongation and defining proarrhythmic risk. In particular, the value of ICH S7B-based "double-negative" nonclinical findings (low risk for hERG block and in vivo QTc prolongation at relevant clinical exposures) is underappreciated. These nonclinical data have additional value in assessing the risk of clinical QTc prolongation when clinical evaluations are limited by heart rate changes, low drug exposures, or high-dose safety considerations. The time has come to meaningfully merge nonclinical and clinical data to enable a more comprehensive, but flexible, clinical risk assessment strategy for QTc monitoring discussed in updated ICH E14 Questions and Answers. Implementing a fully integrated nonclinical/clinical risk assessment for compounds with double-negative nonclinical findings in the context of a low prevalence of clinical QTc prolongation would relieve the burden of unnecessary clinical QTc studies and streamline drug development.

Echocardiographic and hemodynamic indices of myocardial contractility simultaneously evaluated in telemetered beagle dogs: A HESI-sponsored cross-company evaluation.

INTRODUCTION: Alterations in cardiac contractility can have significant clinical implications, highlighting the need for early detection of potential liabilities. Pre-clinical methods to assess contractility are typically invasive and their translation to human measures of cardiac function are not well defined. Clinically, cardiac function is most often measured non-invasively using echocardiography. The objective of these studies was to introduce echocardiography into standard large animal cardiovascular safety pharmacology studies and determine the feasibility of this combination. METHODS: A consortia of laboratories combined their data sets for evaluation. At each site, telemetered beagle dogs, in a 4 × 4 Latin square crossover study design (n = 4), were administered either pimobendan (positive inotrope) or atenolol (negative inotrope) orally at clinically relevant dose levels. Standard telemetry parameters were collected (heart rate, mean arterial blood pressure, etc.) continuously over 24 h, as well as derived contractility endpoints: QA interval and LV +dP/dtmax. At Tmax, echocardiography was performed in conscious dogs with minimal restraint to collect contractility parameters: ejection fraction (EF) and fractional shortening (FS). RESULTS: Correlations between telemetry and echo contractility endpoints showed that, in general, a change in LV +dP/dtmax of 1000 mmHg/s translates to a 5.2% change in EF and a 4.2% change in FS. Poor correlations were shown between QA interval derived simultaneously, to both EF and FS. DISCUSSION: Comparing data from telemetry-only groups to those that included echocardiography collections showed no effect in the ability to interpret test article-related effects, providing the foundation for the inclusion of echocardiography without compromising standard telemetry data quality.

INSPIRE: A European training network to foster research and training in cardiovascular safety pharmacology.

Safety pharmacology is an essential part of drug development aiming to identify, evaluate and investigate undesirable pharmacodynamic properties of a drug primarily prior to clinical trials. In particular, cardiovascular adverse drug reactions (ADR) have halted many drug development programs. Safety pharmacology has successfully implemented a screening strategy to detect cardiovascular liabilities, but there is room for further refinement. In this setting, we present the INSPIRE project, a European Training Network in safety pharmacology for Early Stage Researchers (ESRs), funded by the European Commission's H2020-MSCA-ITN programme. INSPIRE has recruited 15 ESR fellows that will conduct an individual PhD-research project for a period of 36 months. INSPIRE aims to be complementary to ongoing research initiatives. With this as a goal, an inventory of collaborative research initiatives in safety pharmacology was created and the ESR projects have been designed to be complementary to this roadmap. Overall, INSPIRE aims to improve cardiovascular safety evaluation, either by investigating technological innovations or by adding mechanistic insight in emerging safety concerns, as observed in the field of cardio-oncology. Finally, in addition to its hands-on research pillar, INSPIRE will organize a number of summer schools and workshops that will be open to the wider community as well. In summary, INSPIRE aims to foster both research and training in safety pharmacology and hopes to inspire the future generation of safety scientists.

Comparison of in vitro and computational experiments on the relation of inter-beat interval and duration of repolarization in a specific type of human induced pluripotent stem cell-derived cardiomyocytes.

We compared a published computational model of the action potential of a specific type of human induced pluripotent stem cell -derived cardiomyocytes (hiPSC-CM) with experimental field potential data with regard to their inter-beat interval and the duration of repolarization. In particular, concomitant changes in inter-beat interval and duration of repolarization were calculated after reduction and/or augmentation of specific ion channel conductances as a surrogate for pharmacological manipulation. The observed mismatches between calculations and experimental data indicate that there is information missing about the cellular test system. Based on our results we hypothesize that, among other currents, the actual If ("funny current") may deviate from the prediction. We show that replacement of the If formulation by alternative equations causes the model predictions to change qualitatively, however, none of the available formulations is actually achieving a satisfactory match with experimental data. We suggest a strategy to clarify whether the mismatch can be completely resolved at all using single cell models and, if yes, how this goal could be reached.

Considerations for an In Vitro, Cell-Based Testing Platform for Detection of Adverse Drug-Induced Inotropic Effects in Early Drug Development. Part 1: General Considerations for Development of Novel Testing Platforms.

Drug-induced effects on cardiac contractility can be assessed through the measurement of the maximal rate of pressure increase in the left ventricle (LVdP/dtmax) in conscious animals, and such studies are often conducted at the late stage of preclinical drug development. Detection of such effects earlier in drug research using simpler, in vitro test systems would be a valuable addition to our strategies for identifying the best possible drug development candidates. Thus, testing platforms with reasonably high throughput, and affordable costs would be helpful for early screening purposes. There may also be utility for testing platforms that provide mechanistic information about how a given drug affects cardiac contractility. Finally, there could be in vitro testing platforms that could ultimately contribute to the regulatory safety package of a new drug. The characteristics needed for a successful cell or tissue-based testing platform for cardiac contractility will be dictated by its intended use. In this article, general considerations are presented with the intent of guiding the development of new testing platforms that will find utility in drug research and development. In the following article (part 2), specific aspects of using human-induced stem cell-derived cardiomyocytes for this purpose are addressed.

Drug safety Africa: An overview of safety pharmacology & toxicology in South Africa.

This meeting report is based on presentations given at the first Drug Safety Africa Meeting in Potchefstroom, South Africa from November 20-22, 2018 at the North-West University campus. There were 134 attendees (including 26 speakers and 34 students) from the pharmaceutical industry, academia, regulatory agencies as well as 6 exhibitors. These meeting proceedings are designed to inform the content that was presented in terms of Safety Pharmacology (SP) and Toxicology methods and models that are used by the pharmaceutical industry to characterize the safety profile of novel small chemical or biological molecules. The first part of this report includes an overview of the core battery studies defined by cardiovascular, central nervous system (CNS) and respiratory studies. Approaches to evaluating drug effects on the renal and gastrointestinal systems and murine phenotyping were also discussed. Subsequently, toxicological approaches were presented including standard strategies and options for early identification and characterization of risks associated with a novel therapeutic, the types of toxicology studies conducted and relevance to risk assessment supporting first-in-human (FIH) clinical trials and target organ toxicity. Biopharmaceutical development and principles of immunotoxicology were discussed as well as emerging technologies. An additional poster session was held that included 18 posters on advanced studies and topics by South African researchers, postgraduate students and postdoctoral fellows.

Considerations for an In Vitro, Cell-Based Testing Platform for Detection of Drug-Induced Inotropic Effects in Early Drug Development. Part 2: Designing and Fabricating Microsystems for Assaying Cardiac Contractility With Physiological Relevance Using Human iPSC-Cardiomyocytes.

Contractility of the myocardium engines the pumping function of the heart and is enabled by the collective contractile activity of its muscle cells: cardiomyocytes. The effects of drugs on the contractility of human cardiomyocytes in vitro can provide mechanistic insight that can support the prediction of clinical cardiac drug effects early in drug development. Cardiomyocytes differentiated from human-induced pluripotent stem cells have high potential for overcoming the current limitations of contractility assays because they attach easily to extracellular materials and last long in culture, while having human- and patient-specific properties. Under these conditions, contractility measurements can be non-destructive and minimally invasive, which allow assaying sub-chronic effects of drugs. For this purpose, the function of cardiomyocytes in vitro must reflect physiological settings, which is not observed in cultured cardiomyocytes derived from induced pluripotent stem cells because of the fetal-like properties of their contractile machinery. Primary cardiomyocytes or tissues of human origin fully represent physiological cellular properties, but are not easily available, do not last long in culture, and do not attach easily to force sensors or mechanical actuators. Microengineered cellular systems with a more mature contractile function have been developed in the last 5 years to overcome this limitation of stem cell-derived cardiomyocytes, while simultaneously measuring contractile endpoints with integrated force sensors/actuators and image-based techniques. Known effects of engineered microenvironments on the maturity of cardiomyocyte contractility have also been discovered in the development of these systems. Based on these discoveries, we review here design criteria of microengineered platforms of cardiomyocytes derived from pluripotent stem cells for measuring contractility with higher physiological relevance. These criteria involve the use of electromechanical, chemical and morphological cues, co-culture of different cell types, and three-dimensional cellular microenvironments. We further discuss the use and the current challenges for developing and improving these novel technologies for predicting clinical effects of drugs based on contractility measurements with cardiomyocytes differentiated from induced pluripotent stem cells. Future research should establish contexts of use in drug development for novel contractility assays with stem cell-derived cardiomyocytes.

Evaluation of cardiovascular and ECG parameters in the normal, freely moving Göttingen Minipig.

INTRODUCTION: The objective of this study was to evaluate the normal cardiovascular and ECG parameters in freely moving minipigs and to use these data as the basis of pharmacological drug safety evaluation. METHODS: 7 Göttingen Minipigs were equipped with radiotelemetry transmitters (ITS). Aortic pressure (AP), left ventricular pressure (LVP), lead II of the ECG and body temperature were continuously monitored. Notocord HEM 4.2 software was used for data acquisition. Power calculations for the various parameters were done to assess appropriate sample sizes. RESULTS: We obtained excellent signal quality and found stable hemodynamic parameters with a low intrinsic heart rate in the Göttingen Minipig. After oral dosing of vehicle, the hemodynamic parameters returned quickly to baseline values indicating that the procedure was well tolerated. The heart rate dependency of the QT interval had to be corrected individually. A sufficient power could be achieved with a sample size of 4 due to the low variability of the parameters measured. DISCUSSION: These are, to our knowledge, the first data documenting the course of systemic arterial and ventricular hemodynamic parameters in the freely moving Göttingen Minipig over 24 h. As such, they may serve as a basis for future studies in which drug effects are studied in these animals.

3,5-Dihydro-imidazo[4,5-d]pyridazin-4-ones: a class of potent DPP-4 inhibitors.

Systematic variations of the xanthine scaffold in close analogs of development compound BI 1356 led to the class of 3,5-dihydro-imidazo[4,5-d]pyridazin-4-ones which provided, after substituent screening, a series of highly potent DPP-4 inhibitors.

Safety pharmacology in and for Africa: Establishment of the pre-clinical drug development platform.

Southern Africa (South Africa as well as neighboring countries) has not had an infrastructure for testing the safety of new drugs or other therapeutic entities, including plant-based or herbal treatments coming from the indigenous cultures, according to the current practice and regulatory requirements. Simultaneously, Southern Africa is challenged by very high rates of immune deficiency diseases which have further led to the resurgence of diseases such as tuberculosis, which is commonly thought to be eradicated, at least in Western cultures. Thus, there is high medical need for affordable, effective and safe treatments, but up to now there has been no local expertise and capabilities for state-of-the-art drug testing. Based on an initiative funded by the South African Department of Science and Technology, the Potchefstroom campus of North-West University was chosen for the establishment of a center of excellence for doing rodent-based drug testing research. The centerpiece of the Pre-Clinical Drug Development Platform (PCDDP) is a new rodent vivarium for breeding of SPF rats and mice and associated laboratories for conducting a wide range of physiological and pharmacological studies. Notably, the vivarium has become the first AAALAC-accredited animal facility in Sub-Sahara Africa and is qualified for conducting GLP studies. The establishment of safety pharmacology models is a first priority of the PCDDP, including expertise in studies to examine electrophysiological effects in vitro, and potential CNS, cardiovascular and respiratory effects. The intention is to offer the rodent-based safety pharmacology testing not only to local academic and company-related scientists, but also to those throughout South Africa and neighboring countries.

A new telemetry-based system for assessing cardiovascular function in group-housed large animals. Taking the 3Rs to a new level with the evaluation of remote measurement via cloud data transmission.

INTRODUCTION: A newly developed total implant telemetry system for cardiovascular (CV), electrophysiological and body temperature measurement was evaluated. A cloud-based transmission of the physiological signals allowed an assessment of the quality of the physiological signals despite the physical separation between the instrumented animals and the evaluating home laboratory. The new system is intended to be used for safety pharmacological evaluations of drug candidates in various species. METHODS: Two female minipigs, 6 Labrador-mixed breed dogs and 4 female Cynomolgus monkeys were instrumented with a newly developed total implant system (TSE SYSTEMS). The implants feature a microprocessor, internal memory (1 GB), 2 solid state pressure-tipped catheters, amplifiers and a radio transmitter. Sampling rates for each measurement can be selected within a range between 0.1 and 1 kHz. Biological signals are selected in a programmable fashion on a session-by-session basis according to a user-defined protocol. The pressure sensors are at the tip of an electrical lead having a length customized to each species. Core temperature measurement and activity monitoring (3D accelerometer) are included in the system. Digital transmission range using a single antenna is 5 m with up to 16 animals held together and monitored simultaneously. The range can be expanded with more antennas in an array coupled to a single receiver. The antenna/receiver station consists of a single USB powered mobile unit connected to a PC or laptop. The battery life provides 110 days of continuous recording. The dogs and minipigs were instrumented and monitored in Germany. A novel cloud-based data transmission system was developed to monitor the physiological signals in real-time from the Cynomolgus monkeys, still kept in Mauritius, from the data evaluation laboratory in Germany. After recovery from the surgical implantation, aortic pressure (AP), left ventricular pressure (LVP), ECG and body temperature were recorded for 24 hr monitoring sessions in all animals. Additionally, moxifloxacin (10, 30 and 100 mg/kg) was tested in the dog model using a modified Latin square cross-over study design. RESULTS: The implant was well tolerated and the animals recovered rapidly from the implantation procedure. Excellent signal quality was obtained and stable hemodynamic and electrophysiological parameters could be measured, with little signal artefact or drop-out, over 24 h in each species. After oral dosing of moxifloxacin to the dogs, a substantial, dose-dependent increase in the QT-interval duration could be shown, as anticipated for this agent. Cloud-based data acquisition from the animals in Mauritius and the data evaluation lab in Germany worked well. CONCLUSION: This new CV telemetry system provides a novel alternative to fluid-filled catheter telemetry systems and the coupling to a cloud-based data transmission allows for flexibility in the location of the instrumented animals and data acquisition and the location of the site for data analysis. For the first time it is technically feasible to conduct a CV safety pharmacology study in Cynomolgus monkeys without having to ship them long distances to the home laboratory.

The evaluation of endpoint variability and implications for study statistical power and sample size in conscious instrumented dogs.

INTRODUCTION: The sensitivity of a given test to detect a treatment-induced effect in a variable of interest is intrinsically related to the variability of that variable observed without treatment and the number of observations made in the study (i.e. number of animals). To evaluate test sensitivity to detect drug-induced changes in myocardial contractility using the variable LVdP/dtmax, a HESI-supported consortium designed and conducted studies in chronically instrumented, conscious dogs using telemetry. This paper evaluated the inherent variability of the primary endpoint, LVdP/dtmax, over time in individual animals as well as the variability between animals for a given laboratory. An approach is described to evaluate test system variability and thereby test sensitivity which may be used to support the selection of the number of animals for a given study, based on the desired test sensitivity. METHODS: A double 4 × 4 Latin square study design where eight animals each received a vehicle control and three dose levels of a test compound was conducted at six independent laboratories. LVdP/dtmax was assessed via implanted telemetry systems in Beagle dogs (N = 8) using the same protocol and each of the six laboratories conducted between two and four studies. Vehicle data from each study was used to evaluate the between-animal and within-animal variability in different time averaging windows. Simulations were conducted to evaluate statistical power and type I error for LVdP/dtmax based on the estimated variability and assumed treatment effects in hourly-interval, bi-hourly interval, or drug-specific super interval. RESULTS: We observe that the within-animal variability can be reduced by as much as 30% through the use of a larger time averaging window. Laboratory is a significant source of animal-to-animal variability as between-animal variability is laboratory-dependent and is less impacted by the use of different time averaging windows. The statistical power analysis shows that with N = 8, the double Latin square design has over 90% power to detect a minimal time profile with a maximum change of up to 15% or approximately 450 mm Hg/s in LVdP/dtmax. With N = 4, the single Latin square design has over 80% power to detect a minimal time profile with a maximum change of up to 20% or approximately 600 mm Hg/s in LVdP/dtmax. DISCUSSION: We describe a statistical procedure to quantitatively evaluate the acute cardiac effects from studies conducted across six sites and objectively examine the variability and sensitivity that were difficult or impossible to calculate consistently based on previous works. Although this report focuses on the evaluation on LVdP/dtmax, this approach is appropriate for other variables such as heart rate, arterial blood pressure, or variables derived from the ECG.

8-(3-(R)-aminopiperidin-1-yl)-7-but-2-ynyl-3-methyl-1-(4-methyl-quinazolin-2-ylmethyl)-3,7-dihydropurine-2,6-dione (BI 1356), a highly potent, selective, long-acting, and orally bioavailable DPP-4 inhibitor for the treatment of type 2 diabetes.

A new chemical class of potent DPP-4 inhibitors structurally derived from the xanthine scaffold for the treatment of type 2 diabetes has been discovered and evaluated. Systematic structural variations have led to 1 (BI 1356), a highly potent, selective, long-acting, and orally active DPP-4 inhibitor that shows considerable blood glucose lowering in different animal species. 1 is currently undergoing clinical phase IIb trials and holds the potential for once-daily treatment of type 2 diabetics.