Comparison of non-invasive and implanted telemetric measurement of blood pressure and electrocardiogram in conscious beagle dogs

Comparison of electrocardiogram and blood pressure recording methods in non-rodent toxicology studies: A retrospective analysis

Our study retrospectively examines 51 non-rodent general toxicology studies conducted over the past 8 years to ascertain the influence of recording methodologies on baseline cardiovascular (CV) parameters and statistical sensitivity. Specifically, our work aims to evaluate the frequency of cardiovascular parameter recording categorized by therapeutic modality and study type, to assess the variability in these parameters based on measurement techniques, and to determine the sample sizes needed for detecting relevant changes in heart rate (HR), blood pressure (BP), and QTc interval in non-human primate (NHP) studies. Results indicate that electrocardiogram (ECG) measurements in dogs and NHP were recorded in 63% of studies, combined with BP recording in 18% of studies, while BP was never recorded alone. Trend analysis reveals a decline in the utilisation of restraint-based methods for ECG measurements post-2017, to the benefit of telemetry-based recordings, particularly Jacketed External Telemetry (JET). There was a marked difference in baseline values, with restraint-based methods showing significantly higher HR and QTc values compared to JET, likely linked to animal stress. Further analysis suggests an unrealistic and unethical sample size requirement in NHP studies for detecting biologically meaningful CV parameter changes using restraint-based methods, while JET methods necessitate significantly smaller sample sizes. This retrospective study indicates a notable shift from snapshots short-duration, restraint-based methods towards telemetry approaches over the recent years, especially with an increased usage of implanted telemetry. The transition contributes to potential consensus within industry or regulatory frameworks for optimal practices in assessing ECG, HR, and BP in general toxicology studies.

The evaluation of anti-breast cancer activity and safety pharmacology of the ethanol extract of Aralia elata Seem. leaves

Aralia elata Seem. is a traditional folk Chinese medicinal plant and its leaves have been used to treat many diseases. We aimed to evaluate the anti-breast cancer activity and safety pharmacology of the ethanol extract of A. elata Seem. leaves (ELE). Cytotoxicity was evaluated on human tumor cell lines by MTT assay in vitro. A tumor bearing-nude mice model was used to assess antitumor activity in vivo. Cell apoptosis was determined by Hoechst 33258 staining, flow cytometry and TUNEL staining. The protein levels were determined by western-blotting and immunohistochemical staining. In safety evaluation, ICR mice and beagle dogs were orally administered ELE at different doses to determine its adverse effects on the central nervous system and cardiorespiratory system. ELE significantly inhibited tumor growth and induced cell apoptosis in MCF-7 cells in vitro and in vivo. The protein levels including caspase-3, caspase-9, bax, bcl-2, PARP, and cytochrome c were significantly changed. For the central nervous system, no treatment-related changes in behavior, motor activity or coordination were observed in mice. For the cardiorespiratory system, no significant differences in cardiorespiratory parameters including heart rate, PR interval, RR interval, P wave duration, QRS duration, QTcF interval, respiratory frequency, tidal volume, body temperature, and blood pressure were observed in beagle dogs between the ELE treatment and control group. In conclusion, ELE possessed anti-breast cancer activity by activating a mitochondrial-mediated apoptotic pathway with high biological safety in animals, which indicates it could be a potential therapeutic agent for treating human breast cancer in the future.

Genetic Toxicology and Safety Pharmacological Evaluation of Forsythin

Introduction

Forsythin is the main ingredient of Forsythia suspensa and is widely used in treatment of fever, viral cold, gonorrhea, and ulcers clinically. This study aimed to evaluate the potential genetic toxicity of forsythin and its safety for human use.

Methods

Based on the Good Laboratory Practice regulations and test guidelines, the genetic toxicity of forsythin was assessed by the Ames test, chromosome aberration (CA) test, and bone marrow micronucleus (MN) test in vivo. In the Ames test, five strains of Salmonella typhimurium were exposed to different concentrations of forsythin in the presence or absence of the S9 mixture, and then, the number of His + revertant colonies was counted. In the CA test, Chinese hamster lung (CHL) fibroblast cells were treated with different concentrations of forsythin, mitomycin C, or cyclophosphamide in the presence or absence of the S9 mixture, and the chromosomal aberrations were determined. In the MN test, bone marrow was isolated from the mice with different treatments, and the ratios of polychromatic erythrocytes (PCE) and erythrocytes (PCE/(PCE + NCE)) were measured. Finally, beagle dogs were divided into four groups (negative control, low dose, medium dose, and high dose groups), and then, a telemetry system was used to evaluate the safe use of forsythin.

Results

Ames test results showed that the number of colonies in all test strains with different treatments showed no significantly dose-dependent increase in the presence or absence of the S9 mixture (p > 0.05). In the CA test, the number of cells with aberrations in the CHL fibroblast cells treated with low, medium, and high doses of forsythin for 24/48 h in the absence of the S9 mixture was, respectively, 5.0/2.5, 4.5/1.5, and 5.0/5.0, and in the presence of the S9 mixture, the number was, respectively, 5.0, 5.0, and 4.5. These results showed that there was no significant difference compared to the negative control group either in the presence (2.0) or in the absence (4.0/2.5 for 24/48 h) of the S9 mixture (p > 0.05). The MN test showed that the values of PCE/(PCE + NCE) in the negative, positive controls, and forsythin treatment groups were all more than 20%, which indicated that forsythin had no cytotoxicity. Additionally, no significant toxicological effects of forsythin on blood pressure, respiration, temperature, electrocardiogram, and other physiological indicators in the conscious beagle dogs of different groups were observed by the telemetry method.

Conclusion

Our findings showed that forsythin has low probability of genetic toxicity and no significant toxicological effects, which implied that forsythin is suitable for further development and potential application.

Core battery safety pharmacology testing - An assessment of its utility in early drug development

Requirements for safety pharmacology testing have been in place since the issue of initial regulatory guidance over 20 years ago. An evaluation of such testing, supporting first clinical entry of 105 small molecule drug candidates over the last decade, showed that a "core battery" of in vitro electrophysiological (hERG), conscious non-rodent telemetry cardiovascular, rodent central nervous system (CNS) (modified Irwin's or functional observational battery [FOB] test) and respiratory function (plethysmography) studies was performed. Routine use of the latter 2 studies appears to have limited utility, with only 21% and 28% of studies, respectively, giving findings of which none were identified as of obvious concern to moving the affected drugs into the clinic. The use of a stand-alone hERG assay does not appear to be particular sensitive in predicting proarrythmic risk as a tool by itself. Telemetry study testing had utility especially for identifying effects on QTc interval (about 10% of studies), resulting on some occasions in a lower clinical starting dose and/or increased awareness for potential effects on the cardiovascular system in the Phase I study. Overall, this investigation provides information supporting an overhaul of the current "box ticking" core battery approach used for safety pharmacology testing. However, in order to achieve a more focused examination to investigate potential undesirable pharmacodynamic effects of a new candidate drug and also support 3Rs (Replacement, Reduction and Refinement) thinking in performing unnecessary studies, there will not only need to be a sea change by drug developers but also a change in current regulatory guidance.

Safety pharmacology assessment of Ethanamizuril, a novel triazines coccidiostat

In the current study, to support the safety pharmacology assessment of Ethanamizuril as a new potent anticoccidial agent of triazine compounds, the effects of Ethanamizuril on the central nervous system, cardiovascular system and respiratory system were investigated. Using locomotor activity test, climbing behavior test and nembutal subthreshold hypnotic test at each time point after oral administration of Ethanamizuril to mice, the effects on the central nervous system were evaluated. An assessment of Ethanamizuril effects on the cardiovascular and respiratory system were performed by the use of a telemetry system in conscious beagle dogs. The results showed that the treatment of Ethanamizuril had no effects on motor activity, behavioral changes, coordination, and sensory/motor reflex responses in mice. There were also no changes in heart rate, blood pressure, and electrocardiogram at all doses and each time points in beagle dogs. Our data suggested that Ethanamizuril showed no adverse effects on the central nervous system, cardiovascular system, and respiratory system.

Social housing of non-rodents during cardiovascular recordings in safety pharmacology and toxicology studies

INTRODUCTION

The Safety Pharmacology Society (SPS) and National Centre for the Replacement, Refinement & Reduction of Animals in Research (NC3Rs) conducted a survey and workshop in 2015 to define current industry practices relating to housing of non-rodents during telemetry recordings in safety pharmacology and toxicology studies. The aim was to share experiences, canvas opinion on the study procedures/designs that could be used and explore the barriers to social housing.

METHODS

Thirty-nine sites, either running studies (Sponsors or Contract Research Organisations, CROs) and/or outsourcing work responded to the survey (51% from Europe; 41% from USA).

RESULTS

During safety pharmacology studies, 84, 67 and 100% of respondents socially house dogs, minipigs and non-human primates (NHPs) respectively on non-recording days. However, on recording days 20, 20 and 33% of respondents socially house the animals, respectively. The main barriers for social housing were limitations in the recording equipment used, study design and animal temperament/activity. During toxicology studies, 94, 100 and 100% of respondents socially house dogs, minipigs and NHPs respectively on non-recording days. However, on recording days 31, 25 and 50% of respondents socially house the animals, respectively. The main barriers for social housing were risk of damage to and limitations in the recording equipment used, food consumption recording and temperament/activity of the animals.

CONCLUSIONS

Although the majority of the industry does not yet socially house animals during telemetry recordings in safety pharmacology and toxicology studies, there is support to implement this refinement. Continued discussions, sharing of best practice and data from companies already socially housing, combined with technology improvements and investments in infrastructure are required to maintain the forward momentum of this refinement across the industry.

Inclusion of Safety Pharmacology Endpoints in Repeat-Dose Toxicity Studies

Whereas pharmacological responses tend to be fairly rapid in onset and are therefore detectable after a single dose, some diminish on repeated dosing, and others increase in magnitude and therefore can be missed or underestimated in single-dose safety pharmacology studies. Safety pharmacology measurements can be incorporated into repeat-dose toxicity studies, either routinely or on an ad hoc basis. Drivers for this are both scientific (see above) and regulatory (e.g. ICH S6, S7, S9). There are inherent challenges in achieving this: the availability of suitable technical and scientific expertise in the test facility, unsuitable laboratory conditions, use of simultaneous (as opposed to staggered) dosing, requirement for toxicokinetic sampling, unsuitability of certain techniques (e.g. use of anaesthesia, surgical implantation, food restriction), equipment availability at close proximity and sensitivity of the methods to detect small, clinically relevant, changes. Nonetheless, 'fit-for-purpose' data can still be acquired without requiring additional animals. Examples include assessment of behaviour, sensorimotor, visual and autonomic functions, ambulatory ECG and blood pressure, echocardiography, respiratory, gastrointestinal, renal and hepatic function. This is entirely achievable if the safety pharmacology measurements are relatively unobtrusive, both with respect to the animals and to the toxicology study itself. Careful pharmacological validation of any methods used, and establishing their detection sensitivity, is vital to ensure the credibility of generated data.

Assessment of drug-induced increases in blood pressure during drug development: report from the Cardiac Safety Research Consortium

This White Paper, prepared by members of the Cardiac Safety Research Consortium, discusses several important issues regarding the evaluation of blood pressure (BP) responses to drugs being developed for indications not of a direct cardiovascular (CV) nature. A wide range of drugs are associated with off-target BP increases, and both scientific attention and regulatory attention to this topic are increasing. The article provides a detailed summary of scientific discussions at a Cardiac Safety Research Consortium-sponsored Think Tank held on July 18, 2012, with the intention of moving toward consensus on how to most informatively collect and analyze BP data throughout clinical drug development to prospectively identify unacceptable CV risk and evaluate the benefit-risk relationship. The overall focus in on non-CV drugs, although many of the points also pertain to CV drugs. Brief consideration of how clinical assessment can be informed by nonclinical investigation is also outlined. These discussions present current thinking and suggestions for furthering our knowledge and understanding of off-target drug-induced BP increases and do not represent regulatory guidance.

Methodological innovations expand the safety pharmacology horizon

Almost uniquely in pharmacology, drug safety assessment is driven by the need for elaboration and validation of methods for detecting drug actions. This is the 9th consecutive year that the Journal of Pharmacological and Toxicological Methods (JPTM) has published themed issues arising from the annual meeting of the Safety Pharmacology Society (SPS). The SPS is now past its 10th year as a distinct (from pharmacology to toxicology) discipline that integrates safety pharmacologists from industry with those in academia and the various global regulatory authorities. The themes of the 2011 meeting were (i) the bridging of safety assessment of a new chemical entity (NCE) between all the parties involved, (ii) applied technologies and (iii) translation. This issue of JPTM reflects these themes. The content is informed by the regulatory guidance documents (S7A and S7B) that apply prior to first in human (FIH) studies, which emphasize the importance of seeking model validation. The manuscripts encompass a broad spectrum of safety pharmacology topics including application of state-of-the-art techniques for study conduct and data processing and evaluation. This includes some exciting novel integrated core battery study designs, refinements in hemodynamic assessment, arrhythmia analysis algorithms, and additionally an overview of safety immunopharmacology, and a brief survey discussing similarities and differences in business models that pharmaceutical companies employ in safety pharmacology, together with SPS recommendations on 'best practice' for the conduct of a non-clinical cardiovascular assessment of a NCE.