This editorial introduces the annual themed issue of the Journal of Pharmacological and Toxicological Methods (JPTM) dedicated to methodologies in safety pharmacology. The issue draws on content presented at the 2025 Safety Pharmacology Society Annual Meeting in Utrecht, The Netherlands, which featured 124 posters, many of which are reproduced as abstracts in this volume. The manuscripts primarily focus on advances in core battery safety evaluations and data analysis methodologies, while also highlighting emerging areas of investigation, including applications of artificial intelligence, digital monitoring technologies for enhanced safety assessment, in vitro assays recapitulating a range of organ systems and assessment of the hERG IC10 value as an alternative to the conventional IC50 value. The continued publication of these themed issues over the more than two decades underscores the importance of methodological innovation and evaluation, as well as the central role of safety pharmacology in driving these advancements.

Cardiovascular (CV) parameters such as blood pressure (BP), electrocardiogram (ECG), and heart rate (HR) are routinely assessed in non-rodent toxicology studies, yet measurement quality varies by methodology—namely telemetry (implanted or jacketed) versus restraint-based techniques. This analysis examined how measurement methods affect baseline CV values and sensitivity to drug-induced effects. Data from three sources were analyzed: 495 toxicology studies from seven pharmaceutical companies (2015–2023), FDA recently approved drugs (47 NCEs, 26 NBEs in 2022–2023), and two major CROs (2020−2023). Studies involved dogs, minipigs, or non-human primates with dosing durations up to 52 weeks. Additional literature, proprietary data, and questionnaire informed baseline comparisons and statistical and pharmacological sensitivity. In our toxicology datasets, ECG was commonly collected, whereas BP was not. The selection of ECG and BP recording methods was mostly sponsor-dependent. Telemetry was predominantly used in short-duration studies; restraint-based snapshot methods were common in longer studies. Restraint consistently increased baseline BP and HR values and variability. QTc correction methods under restraint were inconsistent across sponsors/CROs. Statistical analysis was common with telemetry but infrequent under restraint. Case examples show that telemetry detected clinically-relevant BP or QTc changes; however, restraint methods usually did not. These findings demonstrate that restraint methods increase baseline values and variability, reducing pharmacological and statistical sensitivity to detect CV effects. Current practices appear driven by sponsor convention as well as scientific rationale. As ICH S7A/S7B evolve, re-evaluation of CV monitoring methods is warranted to enhance scientific rigor, regulatory alignment, and 3Rs compliance in nonclinical safety assessment.

Safety pharmacology is concerned with the identification and characterization of adverse effects of drug candidates on vital organ systems. The emergence of artificial intelligence (AI) and machine learning (ML) has prompted growing interest in their potential application to nonclinical drug safety evaluation across the core battery cardiovascular, central nervous, and respiratory systems. This review traces the historical development and technical foundations of AI, from early neural network research and backpropagation algorithms to the emergence of modern frontier large language models, and examines how these technologies are being applied to safety pharmacology study endpoints including proarrhythmic risk assessment consistent with International Council for Harmonisation (ICH) S7B and Comprehensive in vitro Proarrhythmia Assay (CiPA) frameworks, seizure liability detection via microelectrode array analysis, and respiratory function monitoring through whole-body plethysmography. The applications of AI in a broader toxicological assessment, including multi-endpoint toxicity prediction, digital pathology, and federated learning consortia, are also reviewed. To gauge current adoption and attitudes within the discipline, a survey of Safety Pharmacology Society (SPS) members was conducted at the 2024 annual meeting (N = 89). The survey revealed that 57% of respondents were not currently using AI tools, although 44% of non-users planned adoption within the following year; 84% of respondents intended to apply AI in preclinical safety development. The evolving regulatory landscape, including the 2025 United States Food and Drug Administration (FDA) draft guidance on AI credibility and the 2026 FDA/European Medicines Agency (EMA) joint guiding principles, is discussed alongside challenges related to data quality, model interpretability, and validation requirements. The findings indicate that while AI tools show promise for specific applications such as structure-based toxicity prediction and automated signal analysis, the safety pharmacology community appropriately demands rigorous validation before integration into regulated workflows. The challenges of model interpretability, data quality, and the absence of prospective validation studies represent substantive barriers that must be addressed through collaborative effort among industry, academia, regulatory agencies, and scientific societies. AI in safety pharmacology is currently best positioned as a complementary analytical tool that may help avoid investing resources in compounds with predictable safety liabilities, rather than as a replacement for expert scientific judgment.

Drug-induced hypertension or hypotension can have significant clinical consequences, yet BP regulation involves complex, multi-level mechanisms, making translational assessment of pressor effects more challenging than for endpoints such as cardiac repolarization (hERG/QT). Current nonclinical BP studies primarily use telemetry in conscious, freely moving non-rodents, enabling continuous high-fidelity hemodynamic monitoring. These models show reasonable concordance with human data, but some translational challenges exist.The Health and Environmental Sciences Institute (HESI) Global Integrative Strategies Working Group (WG) was established to improve nonclinical cardiovascular (CV) safety assessment through more informative, translational preclinical models. After earlier success characterizing drug-induced effects on cardiac contractility, the WG focused on drug-associated blood pressure (BP) changes. Provided here is the importance of nonclinical models in predicting BP changes and associated challenges. A HESI Global multi-site study focused on addressing these gaps is also introduced. The study aimed to evaluate the reproducibility and translatability of the standard telemetered dog model using compounds with well-characterized mechanisms (midodrine, nifedipine, hydralazine, prazosin, milrinone). Early results show consistent hemodynamic profiles across laboratories, with final results published separately, showing utility of this model for BP liability assessment.

Increases in arterial blood pressure (BP) contribute to adverse cardiovascular (CV) outcomes in patients; preclinical effects of a drug on BP are routinely evaluated during the safety pharmacology assessments as outlined in the ICH S7A guidance. A Health and Environmental Sciences Institute (HESI) Consortium initiated a multi-site study with the objective to assess the ability of the standard conscious telemetry instrumented CV dog model to detect drug-induced changes in BP and evaluate translation to human data. The goal of these studies is also to determine the reproducibility and consistency of BP assessment when measured across different laboratories using the same study protocol and recording methodology to detect drug-induced changes in hemodynamics using drugs known to clinically elevate and reduce BP. Animals were chronically instrumented with a BP catheter and ECG electrodes for telemetric collection of hemodynamic and ECG endpoints, respectively. Study endpoints include systolic, diastolic, and mean BP, heart rate, electrocardiogram (ECG), body temperature, and locomotor activity. Drugs evaluated include midodrine (alpha-1 agonist), nifedipine (calcium channel blocker), hydralazine (direct-acting smooth muscle relaxant), prazosin (alpha-1 blocker) and milrinone (phosphodiesterase-3 inhibitor). Drugs were selected based on known pharmacological mechanisms of action, primary cardiovascular effects as well as availability of clinical effect and exposure data. Drugs were evaluated in beagle dogs using a double (8 × 4) Latin square design and administered orally at 3 doses selected to match clinical exposure data with a vehicle control. A full pharmacokinetic profile for each drug was conducted in dogs at doses selected using automated blood sampling (ABS). Initial analysis shows that all 5 positive control drugs show consistent hemodynamic profiles (e.g., BP elevation or reduction) in the dog as seen in humans. These data sets with additional testing at multiple sites will be amenable to further statistical analysis, super-interval analysis and follow-up study endpoint evaluation such as pressure waveform analysis. The results from this chronically instrumented conscious dog model will provide essential information about accuracy and consistency in blood pressure measurement across multiple sites and translation of preclinical BP data to clinical outcomes.

Core battery cardiovascular (CV) parameters [e.g., arterial blood pressure (BP), electrocardiogram (ECG), heart rate (HR)] are recorded in non-rodent safety pharmacology and toxicology studies. Data is used to support drug development in accordance with regulatory guidelines (e.g., ICH S7A. S7B S6, S9 and M3(R2)). However, the quality of measurements varies based on the methods used, ranging from restraint (unacclimated) to telemetry (implanted or jacketed)-based recordings. This analysis reviewed and compared current practice regarding methodological approaches applied to the acquisition of CV data in repeat-dose non-rodent toxicology studies. The data was sourced from 7 Sponsors, 2 major CROs and FDA regulatory drug approvals. Studies evaluated data acquired from dogs or non-human primates (NHP) with study durations up to 52 weeks. A literature-based search and proprietary published examples were used to establish baseline CV values and to ascertain the ability of the different methodologies used to detect drug-induced CV effects. The literature search provided evidence that baseline CV (BP and HR) values are consistently higher in restrained versus non-invasive telemetry methods. Moxifloxacin and proprietary drugs showed that hERG-mediated QTc prolongation was detected in the clinic and in NHP or dog studies using telemetry methods but not in restrained surface‑lead snapshot methods. Data showed that the ECG is collected in most repeat-dose toxicology studies, but BP is usually not collected. Overall, telemetry-based methods account for 61 % of ECG recordings; while much less frequent, restraint-based methods are used for 44 % of BP recordings, when collected. The choice and usage of collection methods is highly sponsor-dependent, with restraint-based methods for individual sponsors ranging from 0 to 100 %. Data showed that telemetry-based methods are predominately used in short-duration studies for drug safety assessments, but restraint-based snapshot methods are used in longer-duration studies. The data compiled thus far serves as a basis to consider CV collection methods used in toxicology studies and to develop recommendations on the measurement of ECG and BP in non-rodent species in support of regulatory safety assessment studies.

Thrombotic complications including myocardial infarction, stroke, venous thrombosis and pulmonary thromboembolism are common causes of drug attrition often discovered at late stages of drug development. Current nonclinical safety assessments include screening tests that detect hemorrhagic complications but do not identify conditions signaling a risk of thrombosis. Our study aimed to identify sensitive tests for detecting prothrombotic imbalance, without overt thrombosis, for use in early nonclinical drug safety assessments in rodents. Sprague Dawley rats were administered different doses of thromboplastin or tranexamic acid to induce variable intensity hypercoagulable or hypofibrinolytic states, respectively. A panel of functional and quantitative assays measuring hemostatic proteins and pathways were evaluated, in concert with traditional coagulation screening tests and blood cell counts. Profound changes were observed with different patterns of test abnormalities for the different stimuli. Measurements of D-dimer and thrombin antithrombin complex concentrations, plasminogen activator inhibitor-1 and Factor VIIa activity were among the most sensitive tests of hypercoagulability. In contrast, hypofibrinolysis was best characterized in a kinetic, turbidimetric assay. Traditional coagulation screening tests were relatively insensitive, and no single test defined the cause of prothrombotic imbalance. Our results demonstrate that customized biomarker panels can detect early drug-induced prothrombotic states in rats arising from distinct mechanisms.

Elevated arterial blood pressure (BP) is highly correlated with adverse cardiovascular (CV) outcomes in patients. The effects of a drug on arterial pressure are routinely evaluated during preclinical safety assessment as outlined in the ICH S7A guidance document. A Health and Environmental Sciences Institute (HESI) Consortium initiated a multi-site study with the objective to assess the ability of the standard conscious telemetered CV beagle dog model to detect drug-induced changes in BP and evaluate translation to human data. Animals will be chronically instrumented with a BP catheter and ECG electrodes for telemetric collection of hemodynamic endpoints. Study endpoints include systolic, diastolic, and mean BP, heart rate, electrocardiogram (ECG), body temperature, and locomotor activity. Drugs evaluated include midodrine (alpha-1 agonist), nifedipine (calcium channel blocker), hydralazine (direct-acting smooth muscle relaxant), prazosin (alpha-1 blocker) and milrinone (phosphodiesterase-3 inhibitor) were selected based on known mechanisms of action as well as availability of clinical exposure data. Drugs will be evaluated in beagle dogs using a single (4 × 4) or double (8 × 4) Latin square design. Drugs will be administered orally at 3 doses selected to match clinical exposure data and a vehicle control. A full pharmacokinetic profile for each drug will be conducted at the doses selected at a single site (Abbvie). Blood samples at participating sites will be drawn to confirm drug exposures predicted from independent pharmacokinetic studies. The goal of these studies is to determine whether the assessment of BP, when measured across different laboratories using the same protocol, can consistently detect drug-induced changes in hemodynamics using drugs known to clinically increase and decrease BP.

The American College of Toxicology (ACT), the Safety Pharmacology Society (SPS) and the Society for Toxicological Pathology (STP) conducted an industry survey in 2024 to assess current industry practices as they relate to neurotoxicity and safety testing of therapeutics. This survey was developed as a follow-up to 2015 survey conducted by the Safety Pharmacology Society (SPS) to identify industry practices as they relate to central, peripheral and autonomic nervous system ('CNS') drug safety testing. In the current survey, there were one hundred thirty (130) respondents from Asia (5 %), Europe (32 %) and North America (64 %). Most respondents (54 %) were from pharmaceutical companies of over 1000 employees. Small molecules (89 %), large molecules (73 %), gene therapy (52 %), cell therapy (41 %) and vaccines (38 %) were the types of modalities developed by respondents. Oncology (72 %) and neurology/psychiatry (64 %) were the most frequent therapeutic indications pursued by companies followed by inflammation (56 %), cardiovascular (48 %), rare/orphan (44 %), metabolic (42 %), infectious (35 %) and respiratory (28 %) diseases. Tremors (81 %), emesis (75 %) and salivation (61 %) were more frequently reported than in the 2015 CNS survey while gait/coordination abnormalities (67 %), convulsion (65 %), and peripheral neuropathy (24 %) were unchanged or decreased when compared to the 2015 survey. Most respondents reported using a modified Irwin's test (90 %) added to toxicology studies (80 %) and/or as a standalone study (71 %), a major change from the 2015 survey where most respondents reported using a standalone study. Survey results reflect an industry shift towards the development of new therapies classified as biologics, cell and gene therapies.

Cardiovascular adverse drug reactions remain a leading cause of drug attrition. They may emerge during non-clinical or clinical development and often remain undetected until post-marketing, prompting increased regulatory focus. Historically, non-clinical cardiovascular safety testing has centered on assessing QT interval prolongation and torsades de pointes risk, primarily via inhibition of the delayed rectifier potassium current IKr. Such focus may overlook broader cardiovascular liabilities affecting other parameters of the cardiovascular system. This review explores the status and limitations of current non-clinical cardiovascular safety assessments, in particular the over-reliance on the core battery studies defined in ICH S7A and S7B and the insufficient use of mechanistic follow-up assessments. We highlight the gaps between the results of non-clinical cardiovascular safety testing and the emergence of cardiovascular adverse drug reactions in later clinical phases or real-world use. We conclude that to narrow the gaps, there is a need to advance non-clinical methods to detect and adequately measure adverse effects on cardiac rhythm, myocardial contraction, blood pressure, and thrombogenicity. The review further discusses emerging trends and challenges for improving translational relevance, including advanced in vitro and in vivo models, and proposes a re-evaluation of outdated regulatory frameworks to better address diverse cardiovascular risks. Emphasis is placed on functional and mechanistic endpoints over structural pathology, aligning non-clinical safety methodologies with clinical outcomes.

INTRODUCTION:Cardiovascular (CV) parameters1 such as blood pressure (BP), electrocardiogram (ECG), and heart rate (HR) are recorded in non-rodent non-clinical safety studies to support drug development. However, measurement quality varies depending on the methodology used, including restraint-based or telemetry (implanted or jacketed) techniques. Measurement quality, in this context, refers to the sensitivity and reliability of CV measurements in affecting baseline values of measured CV parameters and in detecting pharmacological effects. This retrospective multifaceted analysis evaluated the impact of recording methods on baseline CV parameters and their statistical and pharmacological sensitivities in detecting drug-induced CV effects. METHODS:Data were collected from three sources: (i) 495 studies from seven pharmaceutical sponsors (2015-2023), (ii) FDA-approved drugs (47 NCEs, 26 NBEs from 2022 to 2023), and (iii) two major CROs (2020-2023). Studies were conducted in dogs, non-human primates (NHP), or minipigs, with treatment durations of up to 52 weeks. Additionally, literature-based and proprietary data were analyzed to assess baseline CV values and methodology sensitivity. A survey was conducted to evaluate statistical analysis practices in these studies. RESULTS:All 3 datasets showed that the ECG is collected in most repeat dose toxicology studies, but not BP; the findings were largely independent on the modality (i.e., NCE versus NBE) or the indication (i.e., oncology vs. non-oncology). The choice and usage of ECG and BP methods is highly sponsor-dependent, with restraint-based methods for individual sponsors ranging from 0 to 100 %. FDA data showed that telemetry-based methods are predominantly used in short, single dose toxicology/safety pharmacology studies for NCEs. Subsequent studies of longer duration employ predominantly restraint-based snapshot methods. CRO data showed that approximately 30 % of toxicology studies do not include ECGs; however, when an ECG is recorded it is primarily collected in restrained animals using a snapshot approach. BP is infrequently recorded, regardless of methodology, in repeat dose toxicology studies. The de novo analysis and literature-based search showed that baseline BP/HR values were highly variable with consistently higher means under restraint compared to telemetry methods. The root mean square errors for BP/HR were larger under restrained conditions, in both species. Under restrained conditions, the use of fixed formulae for HR-corrected QT resulted in inconsistent QTc values across sponsor and CROs. The survey showed that statistical analysis of ECG/BP data was infrequently performed under restrained conditions in contrast to telemetry-based methods. Proprietary and published case studies showed that drug-induced BP elevation or QTc prolongation observed clinically and in NHP or dog using telemetry were not reliably detected under restraint-based conditions, highlighting limitations of RB methods in CV safety evaluation. The data illustrate that animal restraint reduces the pharmacological and statistical sensitivities to detect CV effects. CONCLUSIONS:ECG and BP recording methods vary based on sponsor preference, experience and/or institutional practices in addition to scientific rationale. Literature and case studies confirm the limitations of restraint-based methods. As ICH S7A/S7B evolve, revisiting CV assessment practices is necessary to align with scientific, technological, regulatory, and 3Rs considerations, ultimately improving best practices for regulatory safety assessment.

This editorial prefaces the annual themed issue on those methods with application to safety pharmacology (SP) in the Journal of Pharmacological and Toxicological Methods (JPTM). Highlighted content is derived from the 2024 Safety Pharmacology Society (SPS) meeting held in San Diego, CA, USA. The meeting showcased 122 posters, many of which are reproduced as abstracts published in JPTM. The manuscripts predominantly reflect updates to core battery safety evaluation and data analysis methods and include areas of novel investigation within SP. The results from several surveys including an updated salary survey by the SPS, current industry practices on neurotoxicity by the ACT, SPS and STP and results on the need to revisit the ICH S7A guidance on safety and secondary pharmacology by EFPIA, JPMA, and PhRMA provide timely updates. Other manuscripts include in vitro assessment methods for sodium channel block using MEA arrays, and a comparison of the in vitro effects of positive control drugs on the hERG channel current using different testing procedures. In vivo cardiovascular manuscripts include an overview of surgical telemetry implantation methods, utility of automated blood sampling methods in SP studies, evaluation of the performance characteristics for common QTc data collection methods, and an evaluation of a clinically used wearable ECG device for use in SP studies. There is also an overview of the impact of respiratory SP and a comprehensive review and comparison of current practices regarding methodological approaches used to acquire CV data in repeat-dose non-rodent toxicology studies. The 21 years of consecutive themed issues on SP methods attends to the importance of methods evaluation and the contribution of SP to the process of methods evaluation.

Previously1, the cardiovascular-contractility systems model described by Fu et al.2 was evaluated and extended using Simcyp™ Designer, a graphical interface platform and physiologically-based pharmacokinetic tool. Model outputs replicated published dog telemetry data1. In the present study, the model was adapted for use in pentobarbital-anaesthetised beagle dogs, utilizing cardiovascular (CV) and exposure data for atenolol and atropine3. Model adaptations included removal of circadian rhythm, attenuation of baroreflex negative feedback, and development of a pharmacokinetic model in Simcyp™ Designer to accommodate intravenous dose escalation and hysteresis. Model simulations and experimental data for atenolol (0.3, 1, and 3 mg/kg/30 min) showed a decrease in dP/dtmax from 2300 to 1800 mmHg/s and mean arterial pressure (MAP) from 120 to 110 mmHg. The model predicts a decrease in heart rate (HR) from 110 to 85 bpm; however, bradycardia was not observed experimentally. For atropine (0.01, 0.03, 0.1 mg/kg/30 min), model outputs and experimental data displayed an increase in HR (124 to 164 bpm) and dP/dtmax (2650 to 3000 mmHg/s). While experimental MAP data decreased from 130 to 120 mmHg, model outputs predicted an increase from 105 to 130 mmHg. Several challenges were encountered during the development of the anaesthetised systems model. Firstly, the study design for the anaesthetised dog differs markedly from that of conscious dog telemetry. Secondly, the extent to which the baroreceptor reflex is attenuated by the anesthesia is unknown. Furthermore, the Fu et al. model2 employs antagonist Kd values to predict haemodynamic effects, rather than in vivo EC50 values. Finally, the decrease in HR predicted by the model following atenolol administration was not observed in anaesthetised dogs, possibly due to low resting cardiac sympathetic tone under the anesthesia. Despite these limitations, the adapted Fu et al.2 model has the potential to maximise the use of anaesthetised CV dog data. Specifically: to interpolate CV effects at intermediate dose levels, derive threshold plasma concentrations for detectable CV effects, and predict the CV effects at doses which cannot be tolerated.1. Mahmud et al. (2023) SPS Meeting, Brussels, Belgium2. Fu et al. (2022) https://doi.org/10.1002/psp4.127743. Antic et al. (2024) https://doi.org/10.1016/j.vascn.2024.107497

Life supportive cardiovascular (CV) parameters [e.g., arterial blood pressure (BP), electrocardiogram (ECG), heart rate (HR)] are recorded in non-rodent safety pharmacology and toxicology studies and data are used to support pharmaceutical drug development in accordance with several guidelines (e.g., ICH M3, S6, S7, S9). Various methodological approaches are used to collect CV parameters on toxicology studies, including fully implantable telemetry, non-invasive jacket telemetry, and short-duration restraint-based measurement from surface ECG leads and a blood pressure cuff, but their robustness and applicability domain differ widely. The challenge of using conscious animals, especially non-human primates, is that arousal behavior, locomotion, body temperature, and sympathetic activation are significant sources of variability that impact CV parameters, thus telemetry methods are the preferred approach. Historically, toxicology studies have incorporated short-duration restraint methods (manual; chemical sedation) to collect brief periods (“a snapshot at one timepoint”) of CV endpoints in a large number of non-rodents (N ≥ 24) after repeat dosing. Non-rodent species, however, demonstrate increased BP and HR in response to room entry and/or manual restraint, which confounds the interpretation of drug-related effects. Published case examples and company experiences indicate that CV waveforms collected under restraint are of low quality, can vary based on body position and sensor placement (skin electrode; pressure cuff), as well as the type of sedative and dose used. In addition, the data captured can be misleading or incongruent with CV safety pharmacology findings in the same animal species. As a result, restraint-induced stress lowers the sensitivity to detect CV changes as measured over a short-duration and has a higher probability for false negative findings. Although functional CV evaluations in restrained animals have been included in toxicology studies for decades, there is no industry consensus on methods, assay performance, or value (translation) for risk assessment. This communication will review the available literature and leverage pharmaceutical and Contract Research Organization (CRO) experiences, and propose recommendations, with an emphasis on short-duration techniques, from the ICH E14/S7B Industry Support Group with the aim to identify how, when, and if short term restraint-based CV data are valuable for nonclinical safety assessment.

The second salary survey of safety pharmacology professionals was conducted in late 2023. This electronic survey was distributed to all members of the Safety Pharmacology Society (SPS). Survey questions assessed demographic variables, professional background, employment type, and annual incomes. Of 463 active SPS members, 120 responses were received. A majority of the responses (56 %) were from North America, followed by Europe (35 %), then Asia-Pacific (9 %). The results of the 2023 salary survey highlight the continued growth in salaries in the field of safety pharmacology and may serve as a valuable resource for current and future safety pharmacologists.

The Health and Environmental Sciences Institute (HESI) is a nonprofit organization focused on resolving global health challenges through collaborative science. HESI achieves this by engaging scientists from around the world in the public, including health regulatory authorities, and private sectors and coalescing around a specific topic. The HESI Cardiac Safety Committee (CSC) officially formed in 2008 to improve public health by reducing unanticipated cardiovascular-related adverse effects from pharmaceuticals or chemicals. Since the publication by Pierson et al. (2013) outlining achievements, the HESI CSC has continued to champion cardiac safety, having a major impact on the field of cardiovascular safety assessments. This has been attained through numerous prospective studies, retrospective analyses, workshops, symposia and more than 24 peer review publications. These publications detail results of the work over the past decade and while reporting results is important, the lasting impacts on the field of CV safety show the real value of collaborative science. Examples of this work include details of the Comprehensive In vitro Proarrhythmia Assay (CiPA) initiative and subsequent updated ICH E14/S7B Q&As, as well as the related stem cell validation studies and best practices. Similarly, challenges and opportunities in both manual and automated patch clamp studies for proarrhythmic prediction and use in an in silico model. A better understanding of assay sensitivity and specificity can lead to better interpretation and implementation. HESI studies on in vivo and in vitro structure and functional assessments have contributed in these areas. Earlier detection of potential failure modes allow for better drug development and design. HESI team are investigating promising new biomarkers to detect hemostatic changes earlier in the process. Answering challenging questions as a collaborative team, sharing data for the benefit of the larger scientific community, and helping young scientists advance their careers are just a few of the outcomes of the last 10 years of the CSC. Future challenges ahead and the direction of the CSC will be offered for input.

Aficamten is a cardiac specific myosin inhibitor in development as a chronic oral treatment for symptomatic hypertrophic cardiomyopathy (HCM). Core battery safety pharmacology studies were conducted in the rat and dog, relevant species for human risk assessment. The acute effects of oral aficamten (0, 1.5, 3, and 9 mg/kg) were evaluated on central nervous and respiratory system function in male rats. Effects were limited to the high-dose level (9 mg/kg). CNS effects included a transient decrease in alertness and arena rearing counts, slight ptosis and body temperature up to 4-h post-dose. Aficamten effects on the respiratory system included an increase in respiratory rate up to 4-h post-dose and a decrease in tidal volume at 4 h post-dose. These effects were transient and resolved by 24 h post dose. In male beagle dogs, aficamten (0.5, 1, or 2 mg/kg/day) was given for 7 consecutive days. Transient hemodynamic effects consistent with the known pharmacodynamic properties of aficamten (decreased cardiac contractility) resulted. These changes were accompanied by an increased heart rate, decreased systolic and pulse pressures at 1 and 2 mg/kg on day 1 and at 2 mg/kg on day 7 as well as an increased left ventricular end diastolic pressure and a decrease in the maximum rate of left ventricular relaxation at 2 mg/kg on Day 1 and 7. These transient changes resolved by 6 h post dose. There were no aficamten-related effects on quantitative or qualitative ECG parameters at any dose level evaluated on either Day 1 or Day 7. These data suggest that non‑adverse, transient hemodynamic effects associated with the primary pharmacodynamic properties of aficamten may be expected in human participants at excessive exposures. The IC50 for hERG current block by aficamten (10 μM) was 3.7 ± 0.6 % (vs. 2.8 ± 0.4 % in vehicle). Higher concentrations could not be tested due to limitations in solubility. Aficamten showed transient changes in CNS, respiratory and cardiovascular function at the highest doses tested which reflects responses consistent with a supratherapeutic dose; there were no effects on the QT interval or hERG channel.

Aficamten (CK-3773274) is a cardiac myosin inhibitor in development for the treatment of hypertrophic cardiomyopathy (HCM), a commonly inherited heart condition often characterized as a disease of the sarcomere. Aficamten reduces pathologic cardiac hypercontractility by selectively binding to an allosteric site on cardiac myosin. To characterize the pharmacology and toxicology of aficamten, a series of nonclinical repeated dose studies were conducted. In a 10-day repeated dose pharmacology study in Sprague Dawley rats, aficamten produced dose-dependent reductions in left ventricular fractional shortening (FS) which were fully reversible within 24 h. Aficamten did not change the ratio of heart weight to tibia length (HW/TL) or left ventricular posterior wall (LVPW) thickness at any dose tested. At a supratherapeutic dose of 6 mg/kg/day, there was a significant increase in interventricular septum (IVS) thickness. Aficamten did not affect mRNA expression of the cardiac injury biomarkers BNP, β-MHC, or ANP. In repeated dose Good Laboratory Practice (GLP) regulatory toxicology studies in Sprague Dawley rats for up to 6 months and beagle dogs for up to 9 months, the primary adverse findings at supratherapeutic doses were consistent across all studies and observed in the heart consisting of atrial/ventricular dilatation that correlated with increased heart weights. These findings were largely reversible and consistent with excessive on-target pharmacology associated with cardiac myosin inhibition. The reversible nature of aficamten-associated adverse effects is supportive of its clinical safety as this property suggests that these findings, should they occur in humans, may also be reversible, limiting long-term human cardiac risk.