De-risking in Tier I CNS safety assessments is the primary function of study design and technical training of laboratory staff observers.

Derisking is not a pharmaceutical industry strategy to reduce time, effort, or costs in drug development. Derisking strategies originated within the National Institutes of Health as a predicate to good science. There is a growing sentiment within drug development programs to diminish the importance of behavioral measures in toxicological studies and in the Tiered Safety assessment plans of the U.S. Regulatory Agencies and the International Commission on Harmonization. The validity and reliability of the Functional Observational Batter (FOB) is critically dependent on consistency and technical quality in each risk assessment plan. US Federal and International drug approval organizations have universally adopted the concept of principles of test construction rather than delineating specific behavioral assay endpoints for inclusion of the FOB in nonclinical safety protocols. The validity and reliability of behavioral observations in standardized neurotoxicity screening is critically dependent on the FOB developed by the Study Director with the Sponsor throughout all stages of testing.. The individual risk factors selected for observation to be included in the early Tier 1 safety program should be determined by the mechanism and mode of action of the test article. The results of Tier I testing are the basis for Tier II testing designs. Critical to the compliance with Good Laboratory Practices is the documentation of training of the operational staff scheduled to conduct all aspects of the established protocol.

CNS Safety Screening Under ICH S7A Guidelines Requires Observations of Multiple Behavioral Units to Assess Motor Function.

In the adoption of behavior as a critical end point in safety pharmacology and neurotoxicity screening, federal regulatory agencies have shifted the predominating scientific perspective from pharmacology back to the experimental analysis of behavior (psychology). Nowhere is this more evident than in tier I safety assessment of the central nervous system (CNS). The CNS and peripheral nervous system have multiple behavioral units of general activity. A complete picture of the motor control neural pathways cannot be measured by any one single approach. The CNS safety protocols under International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use S7A are required to be conducted in accordance with Good Laboratory Practices by trained technical staff. The CNS safety assessments necessitate the inclusion of a thorough and detailed behavioral analysis of home cage activity, the response to handling, and transportation to and observations within an open-field apparatus with ancillary measures of basal muscle tone, muscle strength, and tremor in a functional observation battery, as well as quantitative measurements of 3-dimensional activity in an automated photobeam arena. Cost-cutting initiatives or a radical application of the "reduce use" principle of the 3 Rs only jeopardize the spirit, intent, and predictive validity of tier I safety testing assays dictated by current drug safety guidelines.

Extended recording of LMA in rats: Effects of IV catheters, "comfort jackets" and chamber lids on arterial blood gas parameters.

The standard infrared photobeam locomotor activity system has been used extensively in neurobiology and neuropharmacology to study the functional impact of direct manipulations of the nervous system. There is interest in using the activity monitors to assess the early stages of drug withdrawal in rodents. In a standard twice-daily dosing strategy animals would be dosed at 6:00 am and 5:00 pm for 15 to 30 days. There is interest in using the chambers to assess the early stages of the discontinuation syndrome. Placement of the rodents into the chambers following the scheduled sham or vehicle last dose of a 15- to 30-day subchronic dosing regimen (b.i.d., t.i.d., etc.) and monitoring overnight allows for a quantitative measure of the initial physiological homeostatic acclimation period during the lights-out period. By using the chambers there is no circadian dysrhythmia induced as an experimental confound and objectively verifiable data is generated during the period expected to correspond with the plasma drug levels approaching zero and the onset of discontinuation syndrome. We demonstrated that untreated "normal" rats showed a normal decelerating time-effect curve over the 12-hour monitoring period that was not compromised by restricted access to food and water. Arterial blood gas monitoring before and after 12 h of night-time activity chamber monitoring clearly demonstrated normal respiratory function with no clinical signs of any blood gas-based diagnosis of metabolic dysfunction.

NOEL and NOAEL: A retrospective analysis of mention in a sample of recently conducted safety pharmacology studies.

INTRODUCTION: The concept of characterizing adversity in relation to administered test article dose and/or exposure within toxicology studies has long been considered a normal aspect of the drug safety evaluation enterprise. The typical way this is done in drug safety investigations is by examining study data, often with focus on clinical signs, clinical pathology and histopathology, to determine a No-Observable-Effect-Level (NOEL) and/or a No-Observable-Adverse-Effect-Level (NOAEL). Once established, these, with other information, may be used to identify a safe starting dose in human clinical trials. Although safety pharmacology (SP) is concerned to identify and characterize potentially "adverse" functional effects, NOEL, and particularly NOAEL, traditionally do not have application in SP study interpretation and reporting. METHODS: An anonymized survey of a contract research laboratory master schedule was undertaken to appreciate recent usage of these concepts in GLP (Good Laboratory Practice) cardiovascular, respiratory, and neurobehavioral safety studies. RESULTS: Results across the sample of studies (N = 635) generally confirmed application of appropriate dose selection strategies, as there was a very low proportion (<1%) of observed severe adverse events (antecedent observations ultimately associated with morbidity/mortality). Data further indicated either no mention of NOEL/NOAEL (50%), or alternately, explicit identification of NOEL (28%), or NOAEL (21%). The majority of times a NOAEL was identified, it was also the case that this coincided with the highest dose administered (e.g., there may have been drug-related findings, but these were considered non-adverse across the dose range). DISCUSSION: While the concept of adversity is certainly relevant to nonclinical SP studies, actual current practices appear to reflect a history which generally avoids toxicologically-oriented classifications such as NOAEL. Questions remain regarding the applicability of NOAELs to safety pharmacology studies, including, importantly, the specific circumstances under which such designations of adversity may be considered to add value to understandings of relative risk and risk mitigation in early human clinical trials.

Relative equivalence of CNS safety (FOB) assessment outcomes in male and female Wistar-Han and Sprague-Dawley rats.

In 2006 the National Toxicology Program (NTP) of the FDA shifted to the preferred use of Wistar-Han rats from the more commonly used Sprague-Dawley (SD) strain - and industry followed. While European laboratories preferred the Wistar-Han line, there was a paucity of relevant historical control data in many US research institutions for the new "industry standard" rat strain. In 2010 the NTP reversed its decision and shifted back to SD rats because of reproductive issues with the Wistar strain. For post hoc comparative analyses, we report minimal practical differences in Functional Observational Battery (FOB) data from a large sample of male and female Wistar-Han and SD rats. In summarizing data from the preclinical safety evaluations of the CNS effects of new drugs using the FOB, it is crucial to understand the value of not only how the functional expression of drug effects in the rat are predictive of the human response, but also how and why they differ. What we can predict from the behavioral and physiological response of the designated test system to drug administration is the foundation of "generalizability" to the human's response. Here, we conclude that the use of either SD or WH rat strains in standard CNS safety studies provide equivalent supportive data for CNS safety assessment required for IND approval under the harmonized guidelines.

Repeated "Day 1" FOB testing in ICH S7A safety assessment protocols: The influence of within- and between-session learning.

A large number of CNS safety assessment studies using the standard Functional Observational Battery (FOB) are conducted each year at Contract Research Organizations throughout the globe. Study design characteristics are as varied as the Sponsors for whom they are contracted. Gender inclusion, sample sizes, and timing of the FOBs are generally negotiated during protocol development. The ICH S7A guidelines describe a dose-effect study design for CNS safety assessment to be conducted prior to the first dose administration in man. Additionally, some Sponsors attempt to use the CNS safety FOB to establish both time- and dose-related acute behavioral effects of their compound in this single critical safety study. In this review, we highlight the confounding influences of multiple postdose FOBs (Day 1) versus the more standard, single FOB scheduled near systemic Cmax of the compound. Within- and between-session learning, combined with changes in vigilance/alertness/fatigue in both the animals and raters, can limit the generalizability of the FOB to accurately assess CNS effects under the current guidelines. Rationale is provided as to the tenuous nature of conducting simultaneous time- and dose-effect behavioral assessments as part of the core safety pharmacology programs.

The standardized functional observational battery: Its intrinsic value remains in the instrument of measure: The rat.

The International Conference on Harmonisation's (ICH) Tripartite Guideline on Safety Pharmacology Studies for Human Pharmaceuticals has adopted the requirement that each new test substance must be tested for effects on the central nervous system prior to "first dose in man". This assessment is required to measure, at a minimum, the effects of the substance on general motor activity, behavioral changes, coordination, sensory/motor reflex responses, and body temperatures. To achieve this goal, ICH S7A recommends a neurobehavioral assessment (usually a functional observational battery (FOB) or modified Irwin test), which is generally undertaken in the rat. There seems to be a growing lack of consensus on the value of the FOB to determine CNS safety. This review highlights the importance of the time, effort and cost of training technicians to familiarize with their instrument of measure, so that each observer is better able to identify and document very subtle changes in behavior that will serve to increase the reliability and validity of these assays with respect to CNS safety assessments.

The failure to detect drug-induced sensory loss in standard preclinical studies.

Over the years a number of drugs have been approved for human use with limited signs of toxicity noted during preclinical risk assessment study designs but then show adverse events in compliant patients taking the drugs as prescribed within the first few years on the market. Loss or impairments in sensory systems, such as hearing, vision, taste, and smell have been reported to the FDA or have been described in the literature appearing in peer-reviewed scientific journals within the first five years of widespread use. This review highlights the interactive cross-modal compensation within sensory systems that can occur that reduces the likelihood of identifying these losses in less sentient animals used in standard preclinical toxicology and safety protocols. We provide some historical and experimental evidence to substantiate these sensory effects in and highlight the critical importance of detailed training of technicians on basic ethological, species-specific behaviors of all purpose-bred laboratory animals used in these study designs. We propose that the time, effort and cost of training technicians to be better able to identify and document very subtle changes in behavior will serve to increase the likelihood of early detection of biomarkers predictive of drug-induced sensory loss within current standard regulatory preclinical research protocols.

Abuse liability assessment of hydrocodone under current draft regulatory guidelines.

INTRODUCTION: The abuse liability of hydrocodone was assessed in male Sprague-Dawley rats under the European Medicines Agency, the International Commission on Harmonisation, and the U.S. Food & Drug Administration draft guidelines for the non-clinical investigation of the dependence potential of medicinal products. METHODS: Self-administration, drug discrimination, and repeat-dose two week dependence liability studies were conducted to compare hydrocodone to the prototypical opiates, morphine and oxycodone. RESULTS: Hydrocodone was self-administered, produced an opiate-like subjective discriminative generalization profile and produced a significant discontinuation syndrome following abrupt treatment cessation that was quantitatively and qualitatively similar to morphine and/or oxycodone. CONCLUSION: Hydrocodone has abuse liability more similar to Schedule II opiates than other Schedule III compounds currently controlled under the U.S. Controlled Substance Act.

Reprint of "Safety pharmacology in 2014: New focus on non-cardiac methods and models".

"What do you know about Safety Pharmacology?" This is the question that was asked in 2000 with the inception of the Safety Pharmacology Society (SPS). There is now a widespread awareness of the role of safety pharmacology in drug discovery and increasing awareness among the wider community of methods and models used in the assessment of the core battery required set of safety studies. However, safety pharmacology does not stop with core battery studies. New methods are intensively sought in order to achieve a swifter and more reliable assessment of adverse effect liability. The dynamics of the discipline and method expansion are reflected in the content of this issue of the Journal of Pharmacological and Toxicological Methods (JPTM). We are into the second decade of publishing on safety pharmacology methods and models, reflected by the annual themed issue in JPTM, and on willingness of investigators to embrace new technologies and methodologies. This years' themed issue is derived from the annual Safety Pharmacology Society (SPS) meeting, held in Rotterdam, The Netherlands, in 2013.

Safety pharmacology in 2014: new focus on non-cardiac methods and models.

"What do you know about Safety Pharmacology?" This is the question that was asked in 2000 with the inception of the Safety Pharmacology Society (SPS). There is now a widespread awareness of the role of safety pharmacology in drug discovery and increasing awareness among the wider community of methods and models used in the assessment of the core battery required set of safety studies. However, safety pharmacology does not stop with core battery studies. New methods are intensively sought in order to achieve a swifter and more reliable assessment of adverse effect liability. The dynamics of the discipline and method expansion are reflected in the content of this issue of the Journal of Pharmacological and Toxicological Methods (JPTM). We are into the second decade of publishing on safety pharmacology methods and models, reflected by the annual themed issue in JPTM, and on willingness of investigators to embrace new technologies and methodologies. This years' themed issue is derived from the annual Safety Pharmacology Society (SPS) meeting, held in Rotterdam, The Netherlands, in 2013.

Background variability in standard clinical pathology biomarkers in beagle dogs instrumented with chronic indwelling telemetry devices.

INTRODUCTION: Contemporary best practice recommendations in preclinical cardiovascular safety assessment promote 3Rs principles. This includes the employment of within-subjects experimental designs to evaluate discrete, acute doses of investigational new drugs, as well as the maintenance of stock colonies of appropriate large animal test systems. Such colony species are often tested repeatedly on independent studies with provision of appropriate recovery periods and requisite health status evaluations (e.g., physical examinations, electrocardiographic assessments, clinical pathology evaluations). METHODS: To investigate the utility of the often reiterative process of pre- or inter-study clinical pathology testing to help ascertain health status of non-naïve, telemetered canines (beagle dogs), the present study collated the results of a randomly selected set of animals approximately every three months for a period of three years. RESULTS: Although occasionally a few routine hematology or clinical chemistry endpoints did demonstrate evidence of systematic trending over time, none of the observed fluctuations fell outside the range of expected biological variability, nor would have prevented assignment of any given animal to study. DISCUSSION: The present findings illustrate a high degree of consistency in routinely assessed clinical pathology parameters during the course of chronic telemetry instrumentation in the canine, including relative to historical control data in healthy, experimentally naïve animals of the same species and source, maintained under analogous laboratory conditions. The data suggest that routine assessment of such parameters for the purposes of facilitating judgments concerning suitability for study may represent a pursuit of little overall value, and which may be reasonably accomplished based on alternative, observation-based screening procedures.

Effects of telemetric epicardial leads and ventricular catheters on arrhythmia incidence in cynomolgus monkeys.

INTRODUCTION: Utilization of implantable bio-telemetry devices represents a common approach to contemporary cardiovascular safety assessment. Depending on the specific needs of the study design, and corresponding surgical methodologies employed, application of telemetry devices may have more or less liability to interact with ongoing physiology. The potential for intrathoracic procedures (epicardial/intracardiac ECG lead arrangements, left ventricular catheterization) to influence baseline cardiovascular function, and particularly arrhythmia status is currently an important topic of consideration. METHODS: Two experiments were performed to assess the post-surgical incidence of ventricular arrhythmias in cynomolgus monkeys instrumented with telemetry devices with 1) left ventricular pressure (LVP) transducers and epicardial lead array (N=67), and 2) epicardial lead array without LVP catheter placement (N=55). A third experiment (N=18) was performed to prospectively, and definitively, investigate the effect of chronic left ventricular catheterization on the observed incidences of arrhythmias by means of multiple (pre- and post-surgery) electrocardiographic evaluations conducted on ~24h of data per interval assessed up to ~12months post-implantation. RESULTS: The diversity and number of ventricular rhythm variants was considerably greater in animals instrumented with left ventricular catheters (62/67; 93%) compared to animals instrumented with epicardial leads only (21/55; 38.2%), and surgically naïve animals (9/18; 50%). Prior to surgery, the average frequency of all definitively characterized arrhythmias among experimentally naïve animals was 0.19/h; following surgical implantation of the telemetry device with epicardial leads and ventricular pressure catheter, the overall frequency of arrhythmia increased approximately 40-fold, to 7.19/h. DISCUSSION: Similar to prior investigations in canines, the present results confirm an increased incidence in the rate and variety of ventricular arrhythmias in cynomolgus monkeys when instrumented with telemetry devices equipped with LVP catheters. Instrumentation with epicardial leads was not associated with an increase in arrhythmias above that expected as a function of normal biological variation in experimentally naïve animals of this species.

Influence of surgically implantable telemetry solutions on in-life and post-mortem toxicology endpoints.

INTRODUCTION: Understanding the appropriate application of telemetry and other technologies for nonclinical investigation of functional safety issues in the context of ongoing toxicology evaluations is a current industry challenge. One major issue is related to the potential impact of surgical implantation of a telemetry device on contemporarily established measures of drug toxicity, and potential for confounding pathological issues related to the systemic and local response of the experimental animal to the presence of a foreign body. This study was designed to evaluate the potential local and systemic impact of different implanted telemetry devices with varying requisite degrees of surgical complexity on general toxicology study endpoints. METHODS: Sixteen male beagle dogs 1) no surgical instrumentation [n=4], 2) Jacketed External Telemetry (JET) with femoral artery blood pressure implant (PA-C10 LA) [n=4], or 3) fully implantable (DSI-D70-CCTP) devices [n=8], were assigned to experimental groups and evaluated within the context of a standard repeat-dose toxicology design to determine the potential impact of these treatments on routine in-life and post-mortem toxicological endpoints. RESULTS: Device implantation, regardless of the level of invasiveness/complexity was without effect on any in-life safety parameter, including clinical chemistry and hematology, assessed in the experimental design. Histopathological findings were limited to the expected, primarily minimal to mild localized effects characteristic of a foreign body reaction (fibrosis, inflammation) in the area immediately in contact with the body of the transmitter device and associated sites of ECG lead and pressure catheter interface with local tissues. DISCUSSION: This study represents the first definitive evaluation of the influence of variably invasive telemetry device implantation on standardized, essential toxicology endpoints in the context of a simulated repeated dose experimental design. The data suggest that, when carefully evaluated, the local effects of implanted telemetry devices can be managed in the context of a standard Investigational New Drug (IND)-enabling toxicology study. This study provides support for the potential incorporation of unrestrained cardiovascular assessments via implanted or external telemetry into standard multi-dose toxicology studies.