Antiparasitic medications are drugs used to treat infections caused by parasites like protozoa, helminths, and ectoparasites by either killing the parasite or inhibiting its growth and reproduction. These medications are crucial for treating parasitic diseases and can vary in dosage and administration depending on the type of infection with proper diagnosis being essential for effective treatment. Nevertheless, such drugs can also cause a range of side effects including genotoxicity, depending on the type of medication and the individual's response. Therefore, here we will summarize data on the genotoxic effects of some antiparasitic drugs since many parasites provoke DNA damage per se, and therapy can enhance such genotoxic effects. The DNA-damaging effects of antiparasitic drugs enable the use of some of them for cancer treatment. Since a parasitic disease comes with severe consequences, the cost-benefit should be considered when taking drugs against such a disease even in terms of their potential genotoxicity. While some antiparasitic drugs have shown genotoxic potential in laboratory studies, most are considered safe for human use at therapeutic doses. Long-term or high-dose exposure may carry more risk; moreover, the genotoxic effects of the drugs can interfere with the genotoxicity of the parasitic infection. More research is needed to fully understand the implications for human health. Nevertheless, the present study has confirmed the need for further cytogenetic research and regular patient monitoring to minimize the risk of an adverse event, especially among frequent travellers visiting parasite-affected areas.

Targeted protein degraders (or degraders) are an emerging small molecule drug modality with transformative therapeutic potential. Currently, most degraders are developed for severe life-threatening disorders and engage the E3 ligase cereblon. One barrier to the broader use of degraders is the potential risk of embryofetal toxicity with cereblon-engaging degraders, exemplified by thalidomide. Thalidomide (and analogs, known as immunomodulatory drugs) binds cereblon and modifies its substrate repertoire, leading to degradation of intended and multiple unintended neosubstrates. Some cereblon-engaging degraders have been engineered to avoid the degradation of unintended neosubstrates implicated in teratogenicity, specifically SALL4. Mechanistic links between SALL4 degradation by thalidomide and human teratogenicity have been established; further, SALL4 degradation by thalidomide (and its analogs) has been linked to teratogenicity in susceptible nonclinical species. It is generally accepted that SALL4 degradation is unlikely to be the only mechanism of teratogenicity associated with thalidomide and its analogs. Currently, best practices to evaluate the teratogenicity risk of cereblon-engaging degraders have not been established. Here, we present points to consider in the teratogenicity safety assessment of cereblon-engaging degraders from the perspective of an IQ consortium working group.

CIGB-500 is a product whose active pharmaceutical ingredient is GHRP-6, (Growth Hormone Releasing Peptide-6), a synthetic peptide that allows the rescue of cardiac mass affected during Acute Myocardial Infarction. The objective of the study was to determine the toxicity profile of CIGB-500 in dogs. As general methodology, CIGB-500 was administered daily to dogs by intravenous route for 28 consecutive days. All animals were allocated to four groups: Control, Low-Dose (300 μg/kg/day), Mid dose (1000 μg/kg/day) and High-Dose (2000 μg/μg/day). Hypersalivation, hypoactivity, reduced heart rate, changes in respiration, pale gums and erythema of the head region were observed in some animals administered at 1000 and 2000 μg/kg/day. These clinical signs were transient, and were therefore considered non-adverse. Treatment with CIGB-500 did not result in any adverse macroscopic or microscopic changes. A decrease in heart rate value was noted following CIGB-500 treatment at all dose levels an at the end of recovery period, the heart rate effects at 2000 μg/kg/day were comparable to controls. In conclusion, the daily administration of CIGB-500 at doses up to 2000 μg/kg/day was well-tolerated, findings noted were transient, minor, non-adverse and reversible, and the no observable adverse effect level (NOAEL) was considered to be 2000 μg/kg/day.

The global burden of tuberculosis, particularly multidrug-resistant (MDR) strains of Mycobacterium tuberculosis, necessitates the urgent development of novel and effective therapeutic agents. Natural products derived from plants have long served as an essential resource for drug discovery, offering structurally diverse bioactive compounds. Sphaeranthus indicus, a plant traditionally valued for its medicinal properties, has shown promise as a source of antimicrobial agents. This study evaluated the antimycobacterial potential of S. indicus extracts and the isolated compound ilicic acid against M. tuberculosis HRv and MDR isolates. Hexane, chloroform, and methanol extracts were screened using the microbroth dilution assay, with the hexane extract demonstrating superior activity (MIC: 125 μg/mL) against the HRv strain. Purification of the hexane extract led to the isolation of ilicic acid, which exhibited significant antimycobacterial activity, inhibiting HRv at 125 μg/mL. Against MDR isolates, ilicic acid displayed MIC values of 500 μg/mL for isolate 1, 125 μg/mL for isolate 2, and 250 μg/mL for isolate 3. These findings underscore the therapeutic potential of ilicic acid as a lead compound for developing anti-TB drugs, especially against drug-resistant strains. The study highlights S. indicus as a valuable source for discovering novel antimycobacterial agents, contributing to global efforts to combat TB resistance.

This report summarises the main findings and discussion from the European Commission (EC) workshop on "The Roadmap Towards Phasing Out Animal Testing for Chemical Safety Assessments" which was held in Brussels on 11-12 December, 2023. The aim of the workshop was to gather ideas and opinions from individuals, organisations and institutions, and to discuss potential approaches for incorporating non-animal methods into chemical legislation with all interested stakeholders. The roadmap will be an EC policy document which will outline milestones and specific actions, addressing all relevant pieces of chemical legislation relating to safety assessment. It intends to describe the necessary steps to replace animal testing in pieces of legislation where it is currently required for chemical safety assessments. The roadmap will outline the path to expand and accelerate the development, validation and implementation of non-animal methods as well as means to facilitate their uptake across legislation. The workshop included presentations and discussion from a wide variety of stakeholders. The contributors provided examples of how non-animal methods could be applied to replace, reduce or refine animal testing in the assessment of human health and environmental effects. Furthermore, possible guiding principles for establishing a Next-Generation Risk Assessment (NGRA) in European chemicals legislation were also discussed. The workshop provided the basis for further discussion and for structuring further roadmap work.

Currently, several countries such as China have established regulatory limits for six major mycotoxins in animal feed. However, these limits are primarily designed for single mycotoxin exposure. Co-contamination with multiple mycotoxins is increasingly common, and simultaneous exposure may lead to additive toxic effects. This study aimed to investigate the effects of individual and combined contamination of aflatoxin B (AFB) and zearalenone (ZEA) at China's regulatory limits on the growth performance, oxidative stress, serum biochemistry, immunity indicators, intestinal morphology, liver and kidney histopathology of broilers by incorporating mycotoxin standards into the feed. A total of 432 one-day-old male AA broilers were randomly assigned to four treatment groups, each consisting of six replicates of 18 birds. The control group received a basic diet, while the experimental groups were supplemented with 10 μg/kg AFB, 500 μg/kg ZEA, or a combination of both in the basic diet. The experimental period lasted for 35 days. The results revealed no significant differences among the groups in terms of growth performance, oxidative damage markers, serum biochemistry, cytokine levels, intestinal health, or histopathological assessments of the liver and kidneys. Furthermore, no toxic interactions between the two mycotoxins were observed. Taken together, these results suggest that future assessments should take into account the combined toxicological effects of a wider range of mycotoxins to inform the revision and formulation of feed safety standards.

The skin is the main route of exposure to plant protection products for operators, workers, residents, and bystanders. Assessing dermal absorption is key for evaluating pesticide exposure. The initial approach to risk assessment involves using default dermal absorption values or applying read-across data from experimental results from different formulations. In this way, to support non-dietary pesticide risk assessment focused but not limited to Brazil, this project evaluated 759 GLP-compliant in vitro human skin dermal absorption studies covering 25 formulation types and 248 active substances at multiple concentrations using interpretable machine learning techniques. Bayesian Additive Regression Trees - BART method indicated that Log Pow and molecular weight have the highest importance when predicting dermal absorption; both parameters exhibit moderate interaction uncertainty within each other and with formulation groups water-based and organic-solvent based and with tested form (concentrates or dilutions). The default values for each formulation group were determined using the upper bound of a non-parametric confidence interval for a specified quantile, with calculations conducted via bootstrapping methods; the proposed values correspond to the upper limit of the 95% confidence interval for the 95th percentile: for concentrates, 10% for organic-solvent based, 4% for water-based and 3% for solid formulations. For dilutions, 42% for organic-solvent based, 37% for water-based and 39% for solid formulations. Organic-solvent based dermal absorption values from experimental data can be used as conservative surrogates for solid and water-based formulations. When no experimental data is available for higher spray dilutions of a given formulation type, a pro-rated correction is proposed to a 2 to 5-fold concentration difference, limited to the respective formulation group default value.

The present study aimed to assess, via acute and subacute toxicity studies, the safety of the use of the methanol extract obtained from Crataegus rosei leaves as a self-emulsifying drug delivery system (Cr-SEDDS). For the acute toxicity test, female rats were intragastrically administered single 300 and 2000 mg/kg body weight (bw) doses and followed by an observation period of 14 days. For the subacute toxicity study, female and male rats received a daily 300, 500, and 1000 mg/kg bw dose for 28 days. No decrease in food consumption, body weight, signs of apparent toxicity, or deaths were observed. Macro and microscopic necropsies were performed on the main organs, as were blood chemistry, lipidic parameters, and biometry studies. No significant differences in the levels of liver and kidney biomarkers, the levels of red and white blood cells, or structural alterations were observed in the organs of both the treated and control groups. Therefore, the results of these studies demonstrated that the Cr-SEDDS is non-toxic at repeated doses of up to 1000 mg/kg bw. These data enable the establishment of safe dose levels necessary to continue with in vivo pharmacological studies of this SEDDS for the subsequent development of a phytomedicine for the treatment of cardiovascular diseases.

Nonclinical safety testing (pharmacology, ADME and toxicology studies) needs to occur to support First-In-Human clinical entry for pharmaceutical drug candidates. Examination of the study package from the content of Investigator Brochures (IBs) for 32 small (non-oncology) molecules used to support such entry over a 4-year period (2020-2023) showed that a mean of 38 nonclinical studies were performed per molecule with pharmacology, ADME and toxicology testing contributing 37 %, 39 % and 24 % of the studies, respectively. Examination of IBs used to support clinical entry of 15 small molecule oncology drugs gave similar values of 43 studies contributing 37 %, 42 % and 21 %, respectively. Examination of IBs for 16 biopharmaceuticals showed a mean number of 19 studies per molecule with pharmacology, ADME and toxicology testing contributing 84 %, 5 % and 11 % of the studies, respectively. Overall, for both small molecule and biopharmaceutical drug candidates, similar numbers of pharmacology studies were performed but the approximately 50 % fewer studies for biopharmaceuticals was due to considerably limited ADME and toxicology testing. Comment will be made on how the current study package could be refined (a 3Rs approach) to reduce animal use.

Chemical safety assessment includes evaluating the potential to disrupt the endocrine system in humans and wildlife. The thyroid hormone system shows high complexity which is conserved across vertebrates, allowing biological read-across between regulatory important taxa, namely mammals and amphibians. Potential thyroid disruption in aquatic vertebrates is typically investigated by activity assays (Amphibian Metamorphosis Assay (AMA), Xenopus Eleutheroembryo Thyroid Assay). Since neither assay is designed to provide detailed mechanistic information, mode of action analyses often rely on mammalian data, assuming overall cross-vertebrate conservation. This manuscript elaborates on the imperative that, despite overall conservation, the T-modality in metamorphosing amphibians needs to be understood in detail to justify biological read-across between mammals and amphibians. To this end, we revisit the AMA regarding amphibian developmental physiology, and the T-modality regarding mechanistic cross-vertebrate conservation. The importance of a mechanistic understanding for read-across is showcased based on the AMA's apparent insensitivity to at least one category of prototypical liver enzyme inducers. From a regulatory perspective, deeper mechanistic understanding is needed, not only to strengthen the scientific basis for designing testing strategies and interpreting study results, but also to allow the identification of data gaps and thus development of New Approach Methodologies (NAMs) to minimize vertebrate testing.

HSK21542, a potent and peripherally-restricted kappa opioid receptor (KOR) agonist, is currently being developed to treat postoperative pain and pruritus. Given that conventional opioids (MOR agonists) are widely recognized for their toxicological impacts on the reproductive system and embryonic development, we evaluated the effects of HSK21542 accordingly. The results showed that HSK21542 did not influence male and female fertility or early embryonic development in rats. HSK21542 also did not show significant manifestations of pre- and post-natal development toxicity in rats. In the embryo-fetal developmental study, even though there was a 3.5 % increase in incidence of fetuses with incomplete ossification of thoracic vertebral centrum in the 4 mg/kg/day group, the plasma exposure of HSK21542 in rats at the no observed adverse effect level (NOAEL) was 82.3 times higher than that of human exposure at 1 μg/kg. On the other hand, exposure to HSK21542 during pregnancy in rabbits did not show any teratogenic risk, only causing a minor impact on bone ossification in fetuses. In conclusion, HSK21542 has a favorable safety profile with only minor effects on the embryo-fetal developmental outcomes.

Biocides are widely used in the workplace, mainly in the industrial and healthcare sectors. Because of their potential hazard for human health, their use is regulated on the European market. In particular, the sensitization potential of these substances must be identified in order to implement avoidance of exposure or measures maximizing protection of exposed employees. The objective of this study was to predict the sensitization potential of 24 biocides used in the workplace. For this purpose, the expression of two co-stimulatory markers and four chemokines was analyzed by flow cytometry in murine bone marrow-derived dendritic cells (BMDCs) exposed to the substances. Twenty-two substances induced cell activation with a concentration effect and were identified as sensitizers. Based on the BMDC model, these substances were classified into four potency categories: six extreme sensitizers, twelve strong sensitizers, two moderate and two weak sensitizers. All these biocides, except the ones classified as extreme, induced an upregulation of chemokines secretion in BMDCs. To conclude, the majority of the biocides tested were identified as potential sensitizers. These data underline the need to handle such substances with care in a preventive occupational context.

Risk assessors, managers, and decision-makers are responsible for evaluating diverse human, environmental, and animal health risks. Although the critical elements of risk assessment and management are well-described in national and international documents, the ethical issues involved in risk decision-making have received comparatively little attention to date. To address this aspect, this article elaborates fundamental ethical principles designed to support fair, balanced, and equitable risk-based decision-making practices. Experts and global thinkers in risk, health, regulatory, and animal sciences were convened to share their lived experiences in relation to the intersection between risk science and analysis, regulatory science, and public health. Through a participatory and knowledge translation approach, an integrated risk decision-making model, with ethical principles and considerations, was developed and applied using diverse, contemporary risk decision-making and regulatory contexts. The ten principles - autonomy, minimize harm, maintain respect and trust, adaptability, reduce disparities, holistic, fair and just, open and transparent, stakeholder engagement, and One Health lens - demonstrate how public sector values and moral norms (i.e., ethics) are relevant to risk decision-making. We also hope these principles and considerations stimulate further discussion, debate, and an increased awareness of the application of ethics in identifying, assessing, and managing health risks.

The safety of paper food contact materials (FCMs) is critical for public health, necessitating precise toxicity assessments. This study investigates the impact of sample preparation methods (migration and extraction), liver metabolic enzymes, endogenous ligands, and various cell lines on the in vitro toxicity of paper FCMs. Toxicological endpoints include mutagenicity, genotoxicity, potential estrogenicity, androgenicity, aryl hydrocarbon receptor activity, and cytotoxicity to hepatocytes and the colon intestinal epithelial barrier, using HepG2 and Caco-2 cell lines. Two preparation methods were employed: migration per Commission Regulation (EU) October 2011 and exhaustive Soxhlet extraction. Extraction revealed distinct toxicological profiles compared to migration, exhibiting toxicity in more endpoints, potentially due to different sample conditions affecting chemical identity and concentration. The addition of liver metabolic enzymes altered estrogenic and androgenic activity, while endogenous ligands influenced potency in estrogenicity and androgenicity tests. Integrating extraction and migration methods with physiologically relevant models enhances the evaluation of hazards from paper FCMs. This involves incorporating cell lines that mimic target tissues, such as liver and intestinal epithelium, alongside metabolic enzymes and endogenous ligands in estrogen receptor alpha and androgen activity testing, providing a strategy for the comprehensive assessment of hazards in food contact materials.

Nonclinical developmental and reproductive toxicity (DART) studies are crucial components of novel drug development, as they identify reproductive and developmental risks and ensure drug safety in populations such as pregnant women and women of childbearing potential (WOCBP). Rodents or rabbits are commonly used in nonclinical studies to evaluate DART for chemical compounds. However, for most antibody-based biopharmaceuticals, non-human primates (NHPs) are the only pharmacologically relevant species, necessitating the use of NHPs in DART studies. These studies pose significant challenges due to stringent design requirements, complex protocols, prolonged timelines, and high costs. A single well-designed NHP study, in which the test substance is administered from gestational day 20 until delivery (enhanced Pre- and Postnatal Developmental study, ePPND study), is preferable to conducting separate Embryo-Fetal Developmental (EFD) and Pre- and Postnatal Developmental (PPND) studies. This review highlights the scientific rationale for NHP-based ePPND studies as mandated by major regulatory agencies, discusses advanced methodologies, key challenges (including endpoint selection, experimental design optimization, and data interpretation with case examples), and offers guidance for ePPND design across antibody-based therapeutics.

This work explores the relationship between event prevalence and event observation in the context of a study with a fixed number of subjects. For any given study size, one expects the number of occurrences of a given event to increase as the prevalence of that event increases. We use the Binomial distribution to characterize the likelihood of observing at least one specified event for a fixed sized study over a range of prevalence values. From this, we explore the marginal impact on that likelihood as the study size increases. We present findings regarding the value of prevalence that maximizes the marginal impact of adding one additional subject to a study. We then explicitly characterize the interaction of prevalence and sample size in yielding event observation and provide a vehicle by which study planners may design studies based on risk of non-detection as opposed to traditional power calculations.

Occupational health standards, worker safety and effective regulatory classification relies upon characterisation of occupational asthma and discrimination between allergic asthma, irritant-induced asthma, and work-exacerbated asthma, and the accurate identification of chemical allergens of the respiratory tract. No in silico, in vitro or in vivo experimental method can, either alone or in combination, accurately identify chemical respiratory allergens and provide a sound basis for regulatory classification. Measurement of IgE antibody and skin prick testing can characterise allergy to proteins, but not to chemical respiratory allergens. Therefore, characterisation of causation and accurate regulatory classification of work-related asthma relies upon characterisation of clinical and workplace histories and specific inhalation challenge tests conforming to current guidelines and best practice. This manuscript reviews the important of accurate characterisation of causation in cases of work-related asthma to ensure accurate classification and robust regulation, and to promote a sound basis for clinical and experimental research. Commentaries on selected clinical case studies are provided that highlight key issues that confound attribution of causation. Specific recommendations are made regarding the design, conduct and interpretation of clinical investigations of work-related asthma that could provide a basis of more robust regulatory practice, and the more reliable identification of chemical respiratory allergens.

Although the ICH S7A guideline on safety pharmacology largely achieved its objective, a proportion of remaining adverse drug reactions and attrition can be attributed in part to gaps in safety and secondary pharmacology assessments. Advances in science, technology, drug development paradigm and regulatory practices necessitate revisiting and evolving ICH S7A to address these limitations. The anticipated completion of the ICH S7B Q&As by end of 2025 provides an opportunity to integrate its outcomes with ICH S7A into a comprehensive, modality-agnostic sustainable over time framework. Such consolidation could streamline guidance, enhance usability, and align regulatory expectations globally. This proposed revision should aim to address key aspects of safety and secondary pharmacology, including the definition of adversity, the integration of human-relevant in vitro and in silico models, and the adoption of state-of-the-art in vivo platforms. Further considerations should include the development of principles for model and assay validation, the promotion of integrated risk assessment frameworks, and incorporation of weight of evidence approaches. Revised guideline would also emphasize sustainable practices by adapting to evolving therapeutic modalities, while reducing reliance on animal testing through New Approach Methodologies. The revision seeks to enhance the benefit-risk evaluation of drug candidates, refine clinical monitoring, foster regulatory acceptance, and streamline drug development. This comprehensive update has the potential to not only optimize drug safety evaluations but also to align industry practices with modern scientific advancements and ethical considerations, ensuring a more robust and efficient pathway for therapeutic innovation.

Cigarette smoke (CS) exposes users to harmful substances, contributing to chronic lung diseases. Heated tobacco products (HTPs) are marketed as safer alternatives due to their lower toxicant emissions from heating rather than burning tobacco. However, HTPs may produce unique toxicants that are not found in CS. The emissions of carbonyls and tobacco-specific nitrosamines (TSNAs) were compared using targeted analysis using liquid chromatography/ion mobility-quadrupole time-of-flight mass spectrometry (UPLC-MS/MS) and untargeted analysis with UPLC-QToF and Progenesis® QI software. Targeted analysis revealed that HTP aerosol emissions contain significantly lower levels of harmful compounds compared to CS, with reductions of 8.7%-91.6% in 11 carbonyls and 85.7%-95.4% in four TSNAs) Untargeted analysis identified 25 carbonyls and seven nitrosamines in both HTPs and conventional cigarettes, with acetoin, dimethylbenzaldehyde, furfural, and diisopropanolnitrosamine (DIPN) found at relatively high levels in HTPs. While untargeted methods introduce some uncertainty, these findings underscore distinct chemical differences between HTPs and conventional cigarettes. Long-term studies are essential to fully understand the health implications of HTP use.

The European Partnership for Alternative Approaches to Animal Testing (EPAA) held the "New Approach Methodologies (NAMs) User Forum Kick-Off Workshop", at the European Chemicals Agency (ECHA), Helsinki, Finland on 7-8 December 2023. The aim of the User Forum was to gain insight into the regulatory use of NAMs, with a particular reference to Next Generation Risk Assessment (NGRA), for chemical safety assessment. To achieve this, presentations summarised the learnings and experiences of previous EPAA Skin Sensitisation User Forums as well as that of the European Commission's Scientific Committee on Consumer Safety (SCCS). The findings of five case studies were summarised that illustrated the use of NAMs. The presentations and subsequent discussions allowed for learnings and insights to be compiled from all stakeholders with regard to the use of NAMs. Recommendations for the regulatory use of NAMs in NGRA were made, namely for exposure assessment; hazard identification; using tiered and targeted testing strategies; performing risk assessment using NAM data; the practical implementation of NAMs; the use of -omics technologies; and the needs for capacity building and training. The EPAA User Forum provided an open platform for safety assessors to share learnings and experiences. Recommendations for the format and topics of future EPAA User Forums were also made.

This study employs animal-free Next Generation Risk Assessment (NGRA) principles to evaluate the safety of repeated dermal exposure to 2.5% (w/w) HC Yellow No. 13 (HCY13) hair dye. As multiple in silico tools consistently flagged hepatotoxic potential, likely due to HCY13's trifluoromethyl group, which is known to interfere with hepatic lipid metabolism, liver steatosis was chosen as the primary mode of action for evaluation. AOP-guided in vitro tests were conducted, exposing human stem cell-derived hepatic cells to varying HCY13 concentrations over 72 h. The expression of 11 lipid metabolism-related marker genes (AHR, PPARA, LXRA, APOB, ACOX1, CPT1A, FASN, SCD1, DGAT2, CD36, and PPARG) and triglyceride accumulation, a phenotypic hallmark of steatosis, were measured. PROAST software was used to calculate in vitro Points of Departure (PoD) for each biomarker. Using GastroPlus 9.9, physiologically-based pharmacokinetic (PBPK) models estimated internal liver concentrations (C) of HCY13, ranging from 4 to 20 pM. All PoD values significantly exceeded the predicted C, indicating that HCY13 at 2.5% (w/w) is unlikely to induce liver steatosis under the assumed conditions. This research demonstrates the utility of NGRA, integrating AOP-based in vitro assays and computational models to protect human health and support regulatory decision-making without animal testing.