Strategy to replace, reduce or refine vertebrate animal testing under the Canadian Environmental Protection Act, 1999 (CEPA)

Environment and Climate Change Canada
Health Canada

July 2025

Executive summary

The Canadian Environmental Protection Act, 1999 (CEPA) recognizes the need to replace, reduce or refine the use of vertebrate animal testing when assessing the potential harms that substances may pose to human health and the environment. Health Canada (HC) and Environment and Climate Change Canada (ECCC) are working to advance this work on several fronts, including through the development, standardization and incorporation of new approach methods (NAMs) into risk assessment activities. To guide continued efforts towards the replacement, reduction or refinement of vertebrate animal testing under CEPA, HC and ECCC have developed the following strategy. 

This strategy was informed by comments received through the public consultations on the notice of intent, which closed in January 2024, and the draft strategy, which closed in November 2024. A summary of input received through these consultations is available in the What We Heard Reports for the notice and the draft strategy.

This strategy is comprised of 5 elements: (1) the identification and prioritization of NAMs for regulatory needs, (2) advancement of research and data generation, (3) promotion of harmonization and collaboration, (4) communication and consultation with stakeholders, and (5) implementation in CEPA regulatory programs related to the testing and assessment of substances. As part of the strategy, regulatory needs that are currently being met through vertebrate animal testing will be identified, including those for which NAMs are available, are in development or need to be developed. This will inform the prioritization of NAMs and the evaluation of their state of readiness and fit-for-purpose use as well as guide related HC and ECCC research, in alignment and in collaboration with domestic and international efforts. HC and ECCC will also continue to communicate and consult with stakeholders. Together, this work will help guide and promote the use of scientifically justified alternative approaches that replace, reduce or refine the use of vertebrate animals in toxicity testing whenever possible (that is, to the extent practicable and scientifically justified) under CEPA.

1.0 Introduction

1.1 Background

Health Canada (HC) and Environment and Climate Change Canada (ECCC) are responsible for assessing and managing risks from chemicals^{Footnote 1}  under the Canadian Environmental Protection Act, 1999 (CEPA). The Act is the primary legislative framework for pollution prevention in Canada and provides the legislative basis for a range of federal environmental and human health protection programs. A key aspect of CEPA is the prevention and management of risks posed by toxic and other harmful substances^{Footnote 2} . CEPA also manages the environmental and human health impacts of products of biotechnology (including living organisms such as bacteria); marine pollution; disposal at sea; vehicle, engine and equipment emissions; fuels; hazardous wastes; environmental emergencies; and other sources of pollution. Under CEPA, HC and ECCC scientists assess the risks posed to human health and the environment by existing substances that are in commerce in Canada (substances on the Domestic Substances List [DSL]) and new substances intended to be imported into or manufactured in Canada (that are not yet on the DSL). Assessments determine whether these substances pose or may pose a risk to human health or the environment. Other assessment-related activities under CEPA include the prioritization of substances for assessment and the development of the Federal Environmental Quality Guidelines, Guidelines for Canadian Drinking Water Quality, Canadian Ambient Air Quality Standards and the Residential Indoor Air Quality Guidelines.

The risk posed by a substance is determined both by its hazardous properties and by the nature of the exposure that takes place. Determining a chemical’s hazard involves collecting information from various sources including epidemiology studies, toxicity studies in experimental organisms and other supporting information such as computational models and tests conducted using human or animal cells (for example, in vitro assays). A weight of evidence approach is used to assess the potential hazard that a chemical may pose to human health or the environment by integrating information from across these multiple lines of evidence. The amount and quality of available information varies across chemicals, ranging from those that have been well studied (data rich) to those that have not (data poor). For most risk assessments conducted under CEPA, vertebrate animal toxicity tests, which are currently conducted mainly in mice, rats and fish, provide fundamental information for determining the potential hazard that a chemical may pose to human health or the environment. However, studies in experimental animals can present potential ethical concerns and may be expensive and time consuming. In some cases, they may be of limited biological relevance, lack reproducibility or fail to capture effects across diverse species, life stages, environmental compartments, conditions and ecosystems. 

New approach methods (NAMs) are broadly defined as any technology, methodology, approach or combination thereof that can be used to replace, reduce or refine^{Footnote 3}  animal toxicity testing and that may enable more rapid or effective prioritization and/or assessment of chemicals. These methods may include the use of computer-based models (that is, computational, in silico), models based on chemical reactivity (that is, in chemico) and modernized whole-organism assays (for example, the zebrafish embryo model). NAMs may also include assays with biological molecules, cells, tissues or organs, in combination with high-throughput molecular-level data, and exposure prediction approaches. NAMs may also enable high-throughput screening of chemicals and complex mixtures. Further, as research evolves these methods may be able to provide greater information on the variability, susceptibility, and impacts of chemicals on populations who may be disproportionately impacted and vulnerable environments, and present an opportunity to consider additional species of cultural and ecological significance. 

There is an ongoing international effort to replace, reduce or refine the use of traditional vertebrate animal-based toxicity tests, and NAMs present a desired alternative to vertebrate animal-based methods in chemical toxicity testing for the purposes of prioritization and risk assessment. For instance, NAM data can be used to augment the datasets considered in both ecological and human health risk assessments. Further details on how NAM-based approaches have been applied under CEPA are available in this Fact Sheet^{Footnote 4} .  

While there have been some key advancements in the development and implementation of NAMs, there is a commitment to ensuring science continues to progress to the point where these methods can replace vertebrate animal testing, whenever possible (that is, to the extent practicable and scientifically justified), particularly to meet requirements under CEPA for the protection of human health and the environment. For example, there are several complex human health endpoints relating to cancer, reproductive toxicity, developmental toxicity or neurotoxicity that are currently lacking validated or accepted alternative methods. In addition, highly complex interactions within ecosystems cannot currently be understood with NAMs alone. Accordingly, the need for vertebrate animal toxicity testing data continues to be relevant or required for multiple CEPA program areas where validated or accepted alternative testing data are not yet available.

HC and ECCC are committed to the continued advancement of efforts to replace, reduce or refine the use of vertebrate animals in toxicity testing where possible (that is, to the extent practicable and scientifically justified). In line with this, Parliament amended the Food and Drugs Act in June 2023, through the Budget Implementation Act, 2023, No.1 (S.C. 2023 c. 26), to ban cosmetic animal testing in Canada. Parliament also amended CEPA through the Strengthening Environmental Protection for a Healthier Canada Act (S.C. 2023 c. 12). These amendments include a recognition of the need to replace, reduce or refine the use of vertebrate animal testing when assessing the potential harm that substances may pose to human health and the environment. Furthermore, work is underway to amend the New Substances Notification Regulations (NSNR) under CEPA to integrate greater flexibility to accommodate NAMs, which include alternative methods to vertebrate animal toxicity testing. These efforts were signaled in the Notice of Intent on promoting reduced reliance on animal testing in the New Substances Notification Regulations (Chemicals and Polymers)^{Footnote 5}  published in the Canada Gazette, Part I on January 14, 2023. Revised guidance on the New Substances Notification Regulations^{Footnote 6} was also published in 2022 to reflect a commitment to reducing reliance on animal testing.

To guide ongoing and future work in this area, HC and ECCC have developed this strategy.

1.2 Objective

The overarching objective of this strategy is to guide HC and ECCC efforts aimed at achieving the goal of replacing, reducing or refining the use of vertebrate animal testing under CEPA in an iterative and progressive manner when and where possible (that is, to the extent practicable and scientifically justified), in line with the requirements set out in subsection 68.1(1) of CEPA.

The development of this strategy considered comments received during the 60-day public comment periods on the notice of intent, which closed in January 2024, and on the draft strategy, which closed in November 2024. A summary of the input received through these consultations is available in the What We Heard Reports for the notice and the draft strategy.

2.0 Strategy to replace, reduce or refine vertebrate animal testing under CEPA

This strategy consists of 5 elements, as outlined in Figure 2-1. The strategy is intended to be flexible, and its implementation will reflect and keep pace with emerging science and technology and include ongoing engagement with people living in Canada, Indigenous partners and stakeholders. Each element is described in the following sections. Efforts must move forward in coordination with national and international partners, through close collaboration with scientists, industry, regulators and other stakeholders. Given the global nature of chemicals management and the importance of harmonization of regulatory regimes, specific timelines to realize the strategy elements are difficult to forecast, but updates on these timelines will continue to be provided through annual reports to parliament. Of note is that HC and ECCC will continue to advance work on each of these elements in an iterative and progressive manner to support the implementation of NAMs when possible, to the extent practicable and scientifically justified, in line with global efforts towards achieving the meaningful replacement, reduction or refinement of vertebrate animal testing.

Figure 2-1: Elements of the strategy to replace, reduce or refine vertebrate animal testing under the Canadian Environmental Protection Act, 1999 (CEPA)

2.1 Identify and prioritize NAMs for regulatory needs

A critical element towards the goal of replacing, reducing or refining the use of vertebrate animal toxicity testing under CEPA is to identify the main function that vertebrate animal toxicity testing serves in support of chemical risk assessment activities. Vertebrate animal toxicity testing traditionally serves 2 main data needs that are fundamental to regulatory risk assessment and decision-making activities:

1. It identifies adverse effects following exposure to a chemical, which informs hazard characterization; and
2. It provides information on the dose of a chemical required to elicit a hazardous effect (that is, dose-response data), which informs both hazard and risk characterization

Vertebrate animal toxicity tests typically follow test guidelines^{Footnote 7} that have been established by member countries of the Organisation for Economic Co-operation and Development (OECD) or by other organizations (for example, ECCC, the United States Environmental Protection Agency, the American Society for Testing and Materials). Many established tests use a variety of techniques to assess the potential effects of chemicals on human health and the environment. However, since no single test provides information on all the potential hazards that exposure to a chemical may pose, multiple tests may be considered when conducting a risk assessment under CEPA. Not all tests that are considered use vertebrate animals, and some are in fact already based on NAMs. However, despite significant advancements in their development, toxicity testing using NAMs remains at an early stage of regulatory acceptance. Currently, it is still necessary to use vertebrate animal tests to satisfy certain data needs or to meet regulatory requirements for risk assessment, particularly where complex health endpoints are examined (for example, effects on reproduction and development) or where broader impacts on the environment are considered (for example, ecosystem-level effects).

Under CEPA, assessments are conducted on both existing substances that are in commerce in Canada (substances on the DSL) and new substances intended to be imported into or manufactured in Canada (that are not yet on the DSL) to determine if the substance poses or may pose a risk to human health or the environment. For existing substances, there are no prerequisite data requirements, and risk assessments make use of the best available science, including information on chemical properties, environmental fate, hazards, uses and exposures. Relevant data are identified through literature and database searches, information submitted by stakeholders and previous reviews or assessments of substances conducted by other jurisdictions where available and relevant. Information may also be generated by government researchers. Empirical data from key studies, as well as results from models, are used to support proposed conclusions. In the case of new substances, the NSNR^{Footnote 8}  prescribe the information that must be submitted to the Government of Canada to enable risk assessment before a substance is introduced into Canada and to impose restrictions or prohibit use of the substance, where required. Specifically, the NSNR require that physical-chemical property, hazard and exposure information be submitted before the import or manufacture of a new substance, in accordance with stepwise quantity triggers or the conditions or circumstances of introduction in Canada. Other assessment-related activities under CEPA that involve consideration of risk or hazard information include the prioritization of substances for assessment and the development of the Federal Environmental Quality Guidelines, Guidelines for Canadian Drinking Water Quality, Canadian Ambient Air Quality Standards and the Residential Indoor Air Quality Guidelines.

Hazard and risk characterization share commonalities across the various regulatory programs under CEPA. Toxicity tests that cover a broad range of exposure routes, durations and endpoints are considered during the human health and ecological assessment process, where available or required. While alternative methods such as cell and tissue-based tests have been validated for the assessment of local toxicity (for example, skin), complex endpoints, such as systemic toxicity, carcinogenicity or developmental or reproductive toxicity, require additional research to establish approaches that will comprehensively assess this complexity using NAMs. For example, with respect to human health, a key factor in assessing any type of systemic toxicity is an evaluation of the process by which compounds are absorbed, metabolized, distributed throughout the body and excreted, but these processes can be difficult to fully capture with cell-based NAMs. Moreover, currently available cell-based NAMs may lack sufficient biological coverage (that is, are not representative of all tissues) of the target species. Accordingly, it is expected that for most applications, a battery of NAMs will need to be integrated to provide broad coverage of toxicokinetic processes (that is, what the body does to a chemical) and toxicological effects (that is, what the chemical does to the body) relevant to the given exposure route that needs to be addressed.

An identification and prioritization process for NAMs will be developed, which will inform future workplans under this strategy. The prioritization process will follow a stepwise approach in which the use of vertebrate animal toxicity testing to support regulatory decisions, policies and guidelines under CEPA will be examined. NAMs that may serve as alternatives to traditional vertebrate animal testing will subsequently be identified, where available. Concurrently, scientific rigor will be maintained to ensure that regulatory decisions will continue to protect human health and the environment from risks posed by chemicals. As part of the NAM prioritization process, each approach will be evaluated for its respective state of readiness and fit-for-purpose use in regulatory decision-making in both the near and longer term. A starting point for the process will be to prioritize the most frequently cited vertebrate animal toxicity tests in risk assessments under CEPA and identify near- and medium-term opportunities to incorporate scientifically justified alternatives for defined use contexts. Longer-term goals include complex endpoints of regulatory interest (for example, developmental and reproductive toxicity), taking into consideration ongoing international advancements. Another long-term goal is to expand the use of NAMs to better cover areas where existing vertebrate animal models are considered to have limited human relevance or to poorly represent the diversity of species or complexity of ecosystems. Of note, efforts to begin to address some of these longer-term goals have already begun or are planned to begin in the short- or medium-term, but it is anticipated that it will take longer to incorporate scientifically justified alternatives for these endpoints or areas. Adding additional screening methods using NAMs can inform the potential for harm that results from exposure to chemicals under CEPA.

2.2 Advance NAMs research and data generation

To advance the interpretation and incorporation of NAMs into an evolving paradigm of chemical toxicity testing, assessment and decision-making under CEPA, continued research efforts are needed to develop, standardize and establish scientific relevance and confidence to demonstrate the suitability of NAMs for supporting fit-for-purpose uses across regulatory contexts. Fit-for-purpose applications of NAMs will depend on the context and may include use as a standalone test, in tiered testing and/or as part of an integrated approach to testing and assessment (IATA)^{Footnote 9} to support weight of evidence evaluations. Advancing a NAM from the development stage to regulatory use involves significant investments. The timelines required are dependent on several factors, including the endpoint assessed, the current state of the NAM and the level of priority.

To support an evolving transition towards reducing reliance on vertebrate animal toxicity testing, HC and ECCC are leading and collaborating on a range of scientific and research activities related to animal testing alternatives, in alignment and in collaboration with domestic and international partners. The goal is to establish methods that provide broad coverage of toxicological endpoints, and which can be used in the risk assessment process to address regulatory data needs, as described in Section 2.1. NAMs of different levels of complexity may be better adapted to different phases of the assessment process. Additionally, there are regulatory contexts for which NAMs have been used for decades to meet prioritization and assessment needs and which will continue to evolve in terms of their sophistication and relevance to quantitative risk assessment. Recognizing the advantages and limitations offered by the various alternative assays and technologies, research efforts will focus on strategically addressing scientific barriers to advance the use of NAMs to inform risk assessment activities as relevant under CEPA.

There are various ways to characterize how a chemical causes an adverse effect. One example is the use of an Adverse Outcome Pathway (AOP), which is a toxicity pathway composed of a sequence of causally linked events leading to a specific adverse health effect in humans or other organisms. An AOP begins with an interaction between a chemical and a biological target (that is, a molecular initiating event), which leads to a series of key events occurring at different levels of biological organization along the toxicity pathway, resulting in an adverse outcome. The AOP framework adopted by the OECD (as depicted in Figure 2-2) provides a mechanistically informed and structured approach for collecting, organizing and evaluating relevant biological and toxicological information on chemical perturbation to advance hazard characterization and risk assessment. However, AOPs are not designed to be chemical-specific and therefore do not take into account other factors that should be considered, such as how the chemical is absorbed, distributed, metabolized or excreted. Using AOPs as a conceptual framework can help research efforts reduce reliance on animal testing in several ways, including by identifying and describing key biological events and pathways critical to understanding toxicity and by guiding the development and use of NAMs. The AOP framework also enables the integration and contextualization of diverse and complex data sources to derive meaningful insights for hazard identification. Integrating AOP-based approaches into research can help accelerate the transition towards more predictive and mechanistically informed methods that do not rely solely on animal models.

Figure 2-2: Simplified depiction of an adverse outcome pathway (AOP)

Focus areas for ongoing and future research (models and methods)

As depicted in Figure 2-3, the key areas for research span various approaches of increasing complexity and biological relevance and are supported by extending the AOP conceptual framework to human populations and ecosystems. For example, computational modelling and biochemical assays have utility for high-throughput screening and can also be used alongside more complex NAMs to provide multiple lines of evidence or in an IATA. In vitro assays using various cell types can be used to screen for broad cellular responses to chemical exposure or used in a targeted way to assess specific toxicity endpoints. Higher tiered assays, such as tissue or organoid models, may further enhance the biological relevance of the information gained from biochemical and cellular assays alone. Toxicokinetic computational modelling plays an important role in translating a concentration that causes bioactivity in vitro into a target species-relevant external dose. In addition, early life stage whole-organism models (for example, the zebrafish embryo model) have the potential to provide information that can be used to guide the selection of species-specific follow-up NAMs and may serve as an important bridge between in vitro and in vivo testing. Data science approaches are also emerging as high-value tools for integrating, interpreting and communicating all data sources to support the assessment of the risks that chemicals may pose to human health and the environment. Finally, epidemiological and biomonitoring studies and ecological population modelling may provide complementary information to NAMs. Each of these focus areas is rapidly evolving, and research is required to develop, refine and standardize methods on the path to regulatory acceptance. Through a focus on mechanistic information and different levels of biological organization, the AOP conceptual framework recognizes the interconnectedness between human health and healthy environments (that is, clean, healthy and sustainable). As NAMs are developed and validated, they will be considered, as possible, in both human health and environmental risk assessment activities.

Figure 2-3: A vision for human health and the environment

Computational modelling (in silico)

Computational modelling represents a continuum of different methods used to predict the activities and properties of untested chemicals, or chemicals with missing information, based on their structural similarity to chemicals with known toxicities or properties. For example, if sufficiently robust, computational models can predict whether a chemical will be active/positive in a particular in vitro or in vivo toxicity assay. Machine learning and other fields in artificial intelligence (AI) are also rapidly emerging and show great potential for improving the training of computational models and advancing predictive and mechanism-based toxicology. Predictions from computational models can help shape the selection of further follow-up laboratory testing using cellular- and tissue-based NAMs.

Computational methods for toxicokinetic modelling, such as in vitro-in vivo extrapolation (IVIVE), are used to translate a minimal concentration that induces bioactivity in an in vitro experiment into a relevant human or ecological receptor external dose. This is achieved by predicting the equivalent external dose that is expected to cause the biological perturbation observed in a cellular or tissue model using both physiological and chemical-specific information.

Biochemical assays

Biochemical assays are methods that can be used to identify the effects of chemicals on biological molecules. They can provide mechanistic information on the potential effects of a chemical, contributing to our understanding of a chemical’s toxic mode of action. Biochemical assays can be used to identify chemical interactions with key proteins. They are typically designed to be carried out fairly quickly and in a high-throughput manner.

Cellular assays

Cellular assays encompass a wide range of in vitro methods, including both high-content assays that provide broad information on chemical-induced bioactivity and targeted assays for specific toxicological endpoints. In addition, cellular assays are used to quantify the concentration at which effects are observed. Many cellular assays are high-throughput and can be carried out in various types of cells from the target species of interest, including immortalized cells, induced pluripotent stem cells and primary cells.

Omics approaches (for example, high-throughput genomics, transcriptomics, metabolomics or proteomics) and high-throughput phenotypic profiling are high-content assays that are used to simultaneously quantify cellular changes across many features (for example, gene expression, metabolites, proteins). For example, transcriptomics measure changes in gene expression, a process that cells use to regulate their behaviour and response to chemical exposure and can identify chemicals capable of inducing significant bioactivity. Additionally, biomarker or cellular signature analyses can be used to inform on biomolecular interactions and mechanisms of toxicity induced by chemical exposure. In high-throughput phenotypic profiling, fluorescently stained cells are imaged to quantify cellular phenotypic changes in response to chemical exposure.

Targeted assays are designed to detect a specific toxicity endpoint. Some examples of targeted assay types include those for the detection of chemical-induced genetic toxicity (that is, DNA damage, mutations, or changes in chromosome structure or number), immunotoxicity, neurotoxicity and endocrine disruption.

Early-life stage and non-vertebrate whole organism models

This research area includes early life stage whole-organism models such as zebrafish (Danio rerio), fathead minnow (Pimephales promelas), rainbow trout (Oncorhynchus mykiss) and amphibians such as Xenopus spp. embryo-larval assays conducted before the onset of exogenous feeding. These whole-organism NAM models are potentially informative for predicting internal chemical exposure and fate, and morphological, behavioural, toxicokinetic and high-throughput molecular profiling evaluations can also be carried out with them. Furthermore, in addition to contributing to ecological assessments, non-vertebrate whole-organism models may help support the transition from vertebrate animal toxicity testing and further advance omics approaches with respect to assessing the potential harm that substances may pose to the environment.

Tissue and organoid models

Species-specific tissue and organoid models are miniaturized and simplified versions of an organ. These higher-tier assays, also referred to as microtissues or microphysiological systems, can be carried out in the species of interest (for example, human or a wildlife model) and often have a 3D organization that more closely mimics the in vivo cellular environment. As such, these models can provide data that are more reflective of how a chemical would interact with multiple cell types in an organ system. Furthermore, multiple organ models (for example, liver, gut, lung and/or skin) can be integrated to better mimic human physiology and can help capture some of the dynamics of absorption, distribution and metabolism of chemicals. Importantly, omics assays (for example, genomics, transcriptomics, metabolomics, proteomics) and targeted toxicological assays can also be carried out in tissue and organoid models.

Data science

Data science allows researchers to analyze large data sets and interpret and communicate the results. Indeed, the field of regulatory toxicology has become more reliant on data analytics, statistical models and automated approaches to analyze data from high-content assays or across a large number of chemicals. Data science can be used to extract and integrate multiple data streams to support chemical screening, establish research priorities by identifying overarching patterns in data, or drive the development of innovations aimed at introducing efficiencies during the life cycle of risk assessment.

For example, data science can be used in IATA-based workflows, which aim to collect, process, interpret and integrate data from multiple and diverse methods in order to characterize chemical hazards in a more systematic, consistent and transparent manner across thousands of chemicals. Further, the development of AOPs can be applied to IATA workflows to help describe and mechanistically link biochemical and cellular changes to adverse outcomes.

Supportive research: epidemiology and biomonitoring-based approaches

Although not NAMs, epidemiology- and biomonitoring-based approaches may be useful for building confidence towards the use of NAMs. Biomonitoring is the measurement of substances as parent compounds, their metabolites or their reaction products in human or animal tissues and fluids. These measurements provide an indication of an individual’s level of exposure to a substance. In addition, the collection of environmental DNA (genetic material shed by organisms), paired with measurements of chemical concentrations in the environment, can potentially be used as a non-destructive tool to provide information about the distribution of species in the environment and to better understand population-level exposures. Biomonitoring and environmental epidemiology can help increase understanding of real-world exposures to existing chemicals (that is, already in Canadian commerce) and the health effects associated with these exposures. They can also help to identify biomarkers of exposure and effect, inform targeted testing using NAMs and link mechanistic research with population health outcomes, thereby supporting the transition to NAMs.

Moving forward

Looking forward, HC and ECCC will continue to lead a range of scientific and research activities to support these focus areas, guided by regulatory data needs and priorities, as described in Section 2.1. The scale of activities to be undertaken will be dependent on available resources. For instance, to support future activities, investments to expand and transform research laboratory infrastructure and increase high-throughput capabilities will be needed. Investments in information management, technology and data science will also be necessary. This will include building bioinformatic expertise and infrastructures that have the capacity to accommodate and handle the large datasets that NAMs can generate.

HC and ECCC will also continue to collaborate and share findings with domestic and international partners through a variety of knowledge transfer activities, including through publications in scientific journals, conference presentations and participation in working groups and communities of practice. Activities will also take into account global efforts, leveraging them to strategically advance NAMs research, build scientific confidence and avoid duplication of efforts.

2.3 Promote harmonization and collaboration

Given the worldwide nature of chemical manufacturing and use, toxicity testing of chemicals is a global concern. One of the principles followed by member countries of the OECD is the concept of mutual acceptance of data (MAD). To prevent barriers to trade caused by conflicting or duplicative national testing requirements, MAD allows testing data to be accepted across member countries, provided that the testing was conducted according to established guidelines. Many OECD test guidelines currently exist to guide the process of generating data for use in chemical assessments. These guidelines are the basis for program requirements internationally and form an established framework that supports consistent interpretation and use criteria for regulatory decision-making. ECCC has also developed biological test methods, which are well-regarded internationally and relevant to a number of Canadian regulatory contexts. Furthermore, the OECD and additional organizations, such as the Health and Environmental Sciences Institute (HESI) and the International Standards Organization (ISO), have developed internationally harmonized guidance documents and assessment frameworks to support regulatory decision-making.

OECD test guidelines, many of which make use of vertebrate animals, were established over a period of decades and follow a lengthy development and endorsement process.^{Footnote 10} Efforts are underway to develop best practices for novel hazard assessment methodologies and IATA, including guidance on the regulatory use of NAMs, as well as continuing to develop and publish new or updated NAMs-based test guidelines. Collectively, these advances support and facilitate international coordination and harmonization to develop test methods and foster regulatory acceptance of NAMs for endpoints of regulatory interest. However, given the speed at which NAMs are being developed, along with the need to integrate data across many in silico models and in vitro assays to capture the complexity of a living organism, the conventional process of developing test guidelines may pose a challenge moving forward. Therefore, to successfully support the transition towards the use of NAMs in risk assessment, it will also be critical to engage in close collaboration with academia, other governmental organizations, non-governmental organizations, industry, including contract research organizations, and international regulatory partners and organizations. By aligning priorities where feasible and strengthening multi-sectoral collaborations from project conception to completion, research will advance at a faster pace. This will also help advance international harmonization of strategies to facilitate the acceptance and application of new methods and the use of emerging data. Facilitation of these multi-sectoral collaborations and their continued support will be important to ensure a strategic and effective path forward.

HC and ECCC will support knowledge exchange with national and international research and regulatory experts, working together to address research challenges and building on their experiences with implementation under different regulatory frameworks to inform strategic directions and alignment.

Multistakeholder organization initiatives

HC and ECCC will continue to engage in ongoing active leadership and contributions to initiatives aimed at developing internationally recognized test guidelines for NAMs, frameworks and guidance documents, as well as updating current documents to replace, reduce or refine existing vertebrate animal-based methods with NAM-based approaches. This priority work will support and help accelerate global efforts to advance NAMs research and regulatory acceptance of NAMs.

HC and ECCC will also continue developing and contributing to translational research case studies to demonstrate the utility of NAMs and develop best practices to translate research into practical prioritization and risk assessment methods. This initiative will include participation in international working groups and scientific committees focused on the development, standardization, validation, and deployment of tools and methodologies for testing and assessment aimed at reducing reliance on vertebrate animal use. Key contributions to uphold the efficient and effective characterization of chemical hazards for decision-making will be made through OECD advisory bodies, expert groups and projects, such as those conducted under the Working Party for Hazard Assessment (WPHA) and the Working Group of National Co-ordinators of the Test Guidelines Programs, as well as activities within HESI committees that focus on the development and use of innovative toxicology approaches for risk assessment. 

Intergovernmental initiatives

In addition to the international multistakeholder initiatives noted above, ongoing direct collaborations with other governmental organizations are critical to help regulatory experts share best practices, scientific advancements, and experience integrating NAMs into assessment frameworks. These exchanges will ultimately help accelerate and build mutual confidence in the implementation of NAMs into decision-making frameworks. Related efforts will include continuing collaborative work with the Canadian Council for Ministers of the Environment, the United States Environmental Protection Agency, the United States Food and Drug Administration, the National Institute of Environmental Health Sciences, the European Chemicals Agency, and the German Federal Institute for Risk Assessment, among others. HC and ECCC will also seek opportunities to collaborate with other federal departments and provincial and territorial governments.

The Accelerating the Pace of Chemical Risk Assessment^{Footnote 11} (APCRA) initiative is another key forum through which HC and ECCC will continue to collaborate with international governments on NAMs. This international governmental initiative, co-led by Canada, was developed to facilitate the translation of research into regulatory applications by strategically addressing barriers and identifying opportunities to advance the use of NAMs in chemical risk assessment.

Research collaborations

There is a large and growing body of scientific work being carried out on NAMs, both within the private and non-profit sectors as well as in academic and governmental institutions. HC and ECCC will continue to promote collaborative multi-disciplinary research with teams across Canada and internationally as priorities align. These ongoing partnerships and collaborations are critical for success, given that the development of NAMs is resource and time intensive, and beyond the ability of any one organization to undertake alone. Focusing on Canadian regulatory frameworks and enhancing research collaborations across various fields will help drive forward Canadian priorities and, in parallel, help ensure that Canada remains a leader in NAMs development and implementation.

2.4 Communicate and consult with stakeholders

Communication and consultation

HC and ECCC are committed to clearly communicating new NAM-based testing and assessment strategies to people living in Canada, Indigenous partners and other interested parties in order to promote open and transparent science, knowledge exchange, and opportunities for data sharing with national and international collaborators. This includes a commitment to carrying out public consultations as progress is made toward the replacement, reduction or refinement of vertebrate animal toxicity testing under CEPA.

HC and ECCC are also committed to the continued development of NAM-based approaches, which, as part of this process, will be subject to rigorous scientific review. As approaches are developed, HC and ECCC will continue to publish the findings in peer-reviewed scientific journals. Data generated will also continue to be shared through free, publicly available data repositories, including the Government of Canada Open Government Portal, and the Open Science and Data Platform. Canada will continue to advocate for data transparency of NAM-based approaches.

In addition, where NAM-based assessment approaches are developed for key program activities, the practice of publishing Science Approach Documents (SciADs^{Footnote 12}) will continue, as appropriate. A SciAD provides a description of a scientific approach to evaluate the environmental or human health risk of substances. SciADs are published under section 68 of CEPA and do not include regulatory conclusions. However, a key component of the SciAD publication process is the publication of a draft SciAD for public review and comment prior to the use of the approach under CEPA. Several SciADs that outline NAM-based approaches have already been published.

Consultation with stakeholders is key in order to leverage external expertise with NAMs, including stakeholders’ experience and perspectives on the implementation of specific methods (for example, key challenges they may face) and information on alternative methods that they may have developed. In addition, pre-notification consultations will continue to be available for those planning to submit notifications under the NSNR (that is, notifiers) should they have questions regarding the use or acceptability of alternative test methods. During the implementation of this strategy and to inform the path going forward, HC and ECCC will also continue to consult, as required, on specific topics such as the development of any proposed regulatory amendments to the NSNR (Chemicals and Polymers) that promote reduced reliance on animal testing. It is recognized that it may take time for stakeholders and partners to integrate new methods and open and effective communication will be key to ensure that all parties are able to effectively move forward together.

Communicating progress

HC and ECCC recognize that regulators worldwide are working towards a meaningful transition to NAM-based methods over the next decade as the science continues to evolve and mature. Moreover, there is significant public interest in transitioning away from vertebrate animal toxicity testing. As part of open communication with stakeholders to increase transparency, HC and ECCC will explore how to communicate progress related to this strategy. This will include leveraging current regular reporting tools, such as the CEPA Annual Report to Parliament, that provides an overview of the activities conducted and results achieved by the programs each year through CEPA. Updates on key strategy activities, priorities, and challenges, as relevant, will be provided, as well as information on upcoming engagement or learning opportunities and updates describing NAM data use in regulatory activities at HC and ECCC. In addition, the involvement of Government of Canada regulatory and research scientists in key international meetings and working groups pertaining to NAM development and use, and the identification of areas for public engagement or training opportunities could be highlighted. Other communication tools and platforms, such as social media, may also be leveraged to provide key updates. While additional program-specific progress metrics have yet to be determined and will be refined during the implementation of this strategy, they will aim to track advancements in the implementation of NAMs to replace, reduce or refine vertebrate animal testing.

2.5 Implement NAMs in CEPA regulatory programs

HC and ECCC are continuing to work towards the development, standardization, validation or acceptance, and implementation of fit-for-purpose NAMs. Fundamental to these efforts is identifying, communicating and addressing areas of uncertainty, as well as establishing frameworks to guide the continued incorporation of NAM data into regulatory programs and practices. Until the transition towards a more comprehensive use of NAM data, HC and ECCC will consider NAM data, where available and suitable, alongside vertebrate toxicity test data. This will help ensure confidence in the application of NAMs for risk assessment and prioritization while continuing to protect human health and the environment from harmful substances. HC and ECCC are working to implement NAMs in risk assessment and prioritization activities within both the Existing Substances and New Substances programs when possible, as science permits. These programs support the principles of the replacement, reduction or refinement approach in the use of alternative test protocols, where the quality of the information generated to conduct a risk assessment and prioritization is not compromised.

Develop frameworks, criteria and guidance for interpretation and use of NAMs

As NAMs gain regulatory acceptance, HC and ECCC will continue to apply flexibility in accepting alternative data to meet regulatory needs. This will include developing frameworks, criteria and guidance for the interpretation and use of NAMs to guide and promote the use of scientifically justified alternative approaches that replace, reduce or refine the use of vertebrate animals in toxicity testing whenever possible. HC and ECCC will leverage existing reports and available guidance from the international community^{Footnote 13Footnote 14Footnote 15Footnote 16} to develop criteria and guidance for the interpretation and use of NAMs, as well as to adapt a fit-for-Canada evaluation framework. This framework will act as a guiding tool for the evaluation of a given NAM across the criteria for interpretation and use in order to assess the implementation readiness of a NAM and its level of associated uncertainty as well as identify the appropriate context(s) of use. The development of NAM criteria, guidance and frameworks in collaboration and alignment with the international community will enable data obtained from alternative approaches to be used in a more transparent, reliable, and robust manner to supplement, and eventually replace vertebrate animal test data.

Incorporate NAMs into fit-for-purpose approaches

Under CEPA, various approaches have been used for effective chemicals management, covering a wide range of activities including prioritization, rapid screening and more complex risk assessments. Developing fit-for-purpose approaches has been integral to both the Existing Substances and New Substances programs, allowing efforts to be focused on the substances of highest concern and the potential for harm to be assessed as efficiently as possible. Fit-for-purpose approaches allow NAM data of varying complexity and levels of uncertainty to be used, depending on the decision context. For example, the prioritization of chemicals for assessment may use only qualitative in silico data, whereas risk assessment generally requires quantitative dose-response data with less associated uncertainty in order to assess the potential for harm and propose a regulatory conclusion under section 64 of CEPA. NAMs with greater uncertainty at their respective earlier stages of standardization and validation or acceptance may not yet be able to replace the animal toxicity tests necessary for risk assessment but may be considered in addition to traditional data to identify data gaps and provide mechanistic information as part of a weight-of-evidence approach.

HC and ECCC will examine current approaches used in chemicals management and will incorporate NAMs where practical and scientifically sound based on the intended decision context. In the near term, it is anticipated that NAMs will be used most readily in the prioritization of data-poor chemicals and in combination with available animal data for risk assessment. As NAMs continue to be developed, standardized, and validated, the aim is that NAMs will eventually be used more broadly within risk assessment to support regulatory conclusions under CEPA. This implementation will continue to evolve progressively, to the extent practicable and scientifically justified. HC and ECCC are supportive of reduction and refinement approaches in the transition to replace vertebrate animal-based testing and assessment methods, and NAMs may present opportunities to further enhance these ongoing reduction and refinement efforts. This could include work to integrate different toxicological endpoints into a single repeat-dose study, for example contributing to efforts under the OECD, and may also include consideration of the use of short-term in vivo transcriptomics studies, and exploring opportunities to apply tiered testing and assessment approaches under CEPA, where relevant.

Maintain regulatory flexibility

An important part of successfully reducing reliance on animal testing under CEPA will be to investigate areas that specify data requirements and determine if greater flexibility can be incorporated, where appropriate. For example, CEPA’s NSNR (Chemicals and Polymers) prescribe technical information that the notifier must submit using test data or waiver requests. HC and ECCC published a notice of intent^{Footnote 17} in January 2023 indicating that the Government of Canada intends to consider potential amendments to the NSNR (Chemicals and Polymers) to promote the reduced reliance on animal testing and the alignment of regulatory requirements with advancements in science.

In recognition of tests intended to replace, reduce or refine the use of vertebrate animals in traditional toxicity testing, the New Substances program accepts the use of NAMs to meet these technical information requirements where scientifically justified. To be accepted for risk assessment purposes, such data must provide a scientifically valid measure of the endpoint under investigation. For example, information in support of a notifier’s New Substances Notification may be obtained from alternative test protocols, surrogate substances, or via calculation or estimation methods, instead of generating new test data on the notified substance. Alternative protocols may include other domestic or internationally recognized protocols, for example, test methods developed or recognized by the New Substances program. In addition, protocols developed by individual companies or associations may also be acceptable, including, but not limited to, protocols for in vitro screening assays, mechanistic endpoints, as well as transcriptomics and other emerging technologies. The New Substances program assesses whether the alternative protocol provides sufficient information compared to the relevant existing OECD test guideline and ensures the data were produced with a degree of confidence acceptable to the program so that proper evaluations can be conducted.

The Existing Substances program has flexibility to accommodate fit-for-purpose NAMs. Data generated from NAM-based approaches have been increasingly used to support grouping and read-across^{Footnote 18} , prioritization, and assessment of the potential for harm from data-poor existing substances under CEPA. Currently, NAMs that are beginning to be used for prioritization and assessment of existing substances under CEPA are described in SciADs.

Education, training and outreach

Training will continue to be provided to support regulatory and research staff in developing, evaluating and effectively integrating NAMs to address risk assessment data needs. Focus areas for training will include education on the importance of transitioning to NAMs, how to interpret NAM results in the context of an assessment, and how to identify, characterize and communicate uncertainty. Investments will continue to be made in education and training to keep pace with ongoing innovations in the field. Indeed, within HC and ECCC, a community of practice has already been developed to facilitate knowledge transfer between regulatory and research scientists on the use of NAMs for risk assessment applications. Likewise, government regulatory and research scientists will continue to participate in international meetings and conferences to learn best practices from the global regulatory and research communities on the use of NAMs in toxicology and chemical assessment. HC and ECCC programs will also continue to train highly qualified personnel (for example, students at the undergraduate, graduate and postdoctoral levels) in their work, as possible, to help build long-term capacity and knowledge in NAMs. In addition to knowledge transfer activities, Canada will continue to advocate for a common vision that supports a global transition away from the use of animals towards NAMs for regulatory purposes.

Promotion of NAMs within the Government of Canada

Across the Government of Canada, data generated from animal toxicity testing is used to inform regulatory risk assessments and prioritization or to comply with regulatory requirements under legislation other than CEPA. The capacity to transition towards NAMs varies among different program and regulatory regimes depending on the specific legislative requirements for establishing safety and efficacy for different products/uses (for example, industrial substances, drugs, pesticides, foods, natural health products, products of biotechnology) and the availability of validated or accepted NAMs.

Although this strategy is initially being developed in the context of CEPA, it is intended to be adaptable, where possible, to other Government of Canada regulatory programs, enabling a coordinated, strategic approach moving forward. Given that a single method or approach may not be suitable for all situations or regulatory contexts, flexibility and gradual, iterative scientific progress is required. Hence, a suite of NAMs may be required to meet specific data needs in Canada. To support this transition towards the internal implementation of NAMs across the Government of Canada, both for regulatory programs under CEPA and those operating under other Acts, opportunities to harmonize approaches and share best practices will be explored. Existing governance structures will be leveraged to coordinate information and data sharing and to support the strategic advancement of these efforts. Research progress will also continue to be shared on an ongoing basis with internal regulatory partners, and research will be tailored to meet their transitioning priorities and needs.

3.0 Conclusion

Reducing reliance on vertebrate animal testing and promoting methods that replace, reduce or refine the use of vertebrate animal testing is a priority for the Government of Canada. This strategy is an important step to maintain momentum and sets the path forward for related HC and ECCC efforts under CEPA. This strategy is also an important component of the Plan of Priorities mentioned in CEPA subsection 73(1), and responds to the requirement under this Plan to include activities or initiatives to promote the development and timely incorporation of scientifically justified alternative methods and strategies in the testing and assessment of chemicals to replace, reduce or refine the use of vertebrate animals.

As highlighted throughout the strategy, to successfully continue to advance this important commitment, close and coordinated collaboration and dedicated efforts on the part of many, including from Indigenous researchers and partners, academia, industry, non-governmental organizations and other governmental organizations is critical. This transition will take time, and the pace will be dependent on a number of factors, including the rate of scientific progress, and the level of resources and investments, but the Government of Canada will continuously work towards achieving these outcomes. HC and ECCC recognize the important role of the various domestic and international organizations and partners with whom the Departments work, on the development, standardization and regulatory acceptance of alternative test methods. This strategy presents an opportunity to strengthen these partnerships, as well as develop new ones.

As efforts turn towards the implementation of this strategy and advancing efforts under each of the 5 key elements, continued communication and collaboration will be critical to ensure a strategic and effective path forward.