Charles River and Toxys Partner to Advance NAM-Based Developmental Toxicity Testing Through ReproTracker® Collaboration
Charles River Laboratories International, Inc. (NYSE: CRL) and Dutch biotechnology company Toxys have announced a strategic collaboration that aims to reshape the landscape of developmental and reproductive toxicology (DART) testing. Through this partnership, Charles River will provide its clients with access to ReproTracker®, a next-generation human stem cell–based in vitro assay developed by Toxys. This innovative platform enables the rapid, reliable identification of developmental toxicity hazards in pharmaceuticals, agrochemicals, and industrial compounds—representing a key advancement in the ongoing shift toward New Approach Methodologies (NAMs) and animal-free testing solutions.
A Leap Forward in Developmental Toxicology
ReproTracker® is designed to mimic early embryonic development using human induced pluripotent stem cells (iPSCs). By monitoring the differentiation of these stem cells into three germ layers—ectoderm, mesoderm, and endoderm—the assay can detect molecular and morphological changes that signal developmental toxicity. Unlike traditional animal-based teratogenicity tests, which can take months and require extensive ethical and financial investment, ReproTracker® can deliver predictive results within days or weeks, offering an unprecedented balance of scientific rigor, human relevance, and operational efficiency.
The assay’s quantitative outputs can predict the teratogenic potential—or the likelihood that a compound causes birth defects—by identifying disruptions in normal embryogenesis. This allows toxicologists to pinpoint potentially harmful compounds early in the R&D process, reducing the likelihood of late-stage failures and minimizing unnecessary animal testing.
“ReproTracker is a one-of-a-kind in vitro solution to enable safe and effective developmental toxicity testing,” said Dr. Elise Lewis, PhD, ATS, Principal Director and Global Lead of DART (Pharmaceuticals) at Charles River. “DART is a critical step in the nonclinical phase of drug and chemical development, and we are pleased to offer our clients access to a tool that can help ensure the safety of patients and consumers.”
Bridging Traditional and Next-Generation Testing
Developmental and reproductive toxicology studies are indispensable components of the nonclinical safety assessment process, required before a compound progresses into human trials. Traditionally, these studies have relied heavily on in vivo models—typically rodents or rabbits—to assess the risk of congenital abnormalities, infertility, or developmental delays. While effective, these methods are resource-intensive and sometimes limited in their ability to predict human-specific responses.
By incorporating Toxys’s ReproTracker® assay, Charles River is bridging the gap between established DART testing frameworks and next-generation human-relevant NAMs. ReproTracker® can be deployed as:
- An early-phase developmental toxicity screening tool, providing actionable insights before expensive animal studies begin.
- An animal-free teratogenicity testing alternative, aligning with global efforts to replace or reduce animal usage in toxicology.
- A translational research tool, helping to extrapolate findings from animal models to human biology with greater confidence.
“Our collaboration with Charles River enables us to accelerate the adoption of ReproTracker and strengthen its validation as a valuable non-animal alternative to classical in vivo approaches for DART,” added Amer Jamalpoor, Chief Scientific Officer at Toxys.
Reinforcing the 3Rs and the Role of NAMs
This collaboration also aligns closely with Charles River’s Alternative Methods Advancement Project™ (AMAP™)—an initiative focused on integrating innovative, scientifically validated NAMs into toxicological research. The AMAP™ framework supports the internationally recognized 3Rs principles: Replacement (using non-animal methods when possible), Reduction (minimizing the number of animals used), and Refinement (enhancing animal welfare in studies that remain necessary).
Access to ReproTracker® underlines Charles River’s dedication to advancing alternative toxicological methodologies while maintaining the highest standards of patient safety and scientific integrity. The partnership underscores how industry leaders can drive regulatory and scientific acceptance of alternative testing methods that align with global sustainability and ethical imperatives.
Expanding Charles River’s DART Portfolio
The inclusion of ReproTracker® enhances Charles River’s already extensive DART service portfolio. The company provides comprehensive toxicology services across sectors including:
- Pharmaceuticals and biopharmaceuticals, encompassing both small molecules and biologics.
- Vaccines and veterinary products, where developmental safety is critical for regulatory clearance.
- Medical devices, which require safety validation of materials and leachables.
- Agrochemicals and industrial chemicals, where reproductive and developmental safety standards are tightly regulated.
- Food additives and consumer products, requiring early-stage toxicity profiling.
Charles River supports these programs with one of the industry’s largest and most detailed historical control databases, offering deep context for interpreting developmental outcomes and dose-response relationships. The company’s cross-disciplinary DART teams integrate toxicologists, pathologists, and bioinformatics specialists to deliver customized, data-driven insights that streamline the path to regulatory submissions.
The Broader Implications for Global Toxicology
As regulators across the U.S., Europe, and Asia increasingly recognize the scientific validity of NAMs, collaborations such as this one between Charles River and Toxys are poised to redefine toxicological assessment. Agencies including the U.S. Environmental Protection Agency (EPA) and the European Chemicals Agency (ECHA) have both emphasized the need to replace traditional animal studies with validated in vitro and in silico methods wherever feasible.
Toxys’s ReproTracker® has already gained attention in the regulatory community as a promising addition to the NAM toolbox. Its combination of mechanistic insight and high-throughput design allows for both screening and mechanistic hazard identification. The assay has demonstrated reproducibility across multiple laboratories, an essential factor for global validation and acceptance.
By combining Charles River’s regulatory experience and global client base with Toxys’s assay innovation, the partnership is expected to accelerate both scientific validation and regulatory endorsement of human stem cell–based toxicology.
About the Partner Companies
Charles River Laboratories International, Inc. is a leading global provider of preclinical and clinical laboratory services designed to support the discovery, development, and manufacture of new drugs and chemicals. The company serves pharmaceutical and biotechnology companies, government agencies, and academic institutions around the world. Its comprehensive portfolio—ranging from safety assessment and DART to bioanalysis, manufacturing support, and nonclinical research—enables clients to accelerate development timelines and improve the predictability of human outcomes.
Charles River’s workforce of dedicated scientists and professionals is united by a mission to enhance the quality and safety of life-saving therapies. To learn more about the company’s offerings, visit www.criver.com.
Toxys, headquartered in the Netherlands, is a pioneering biotechnology company devoted to improving chemical safety assessment through in vitro, animal-free testing platforms. The company’s suite of assays—such as ToxTracker® for genotoxicity and ReproTracker® for developmental toxicity—are designed to reveal mechanistic insights into toxicity pathways, allowing researchers to predict adverse outcomes with high accuracy.
With a strong focus on scientific validation, regulatory alignment, and sustainability, Toxys collaborates with academic institutions, industrial partners, and government agencies worldwide. Its mission is to transform toxicology into a more human-relevant, ethical, and cost-effective discipline.
A Vision for the Future
The Charles River–Toxys collaboration represents more than a business partnership—it reflects a larger paradigm shift occurring across the toxicology and drug development sectors. As NAMs continue to mature, the combination of in vitro models, computational approaches, and advanced imaging technologies will redefine how developmental toxicity is understood and managed.
By integrating ReproTracker® into its DART portfolio, Charles River is reaffirming its role as a global leader in scientific innovation and regulatory readiness. For Toxys, this collaboration opens new pathways for international adoption of its assay technologies, accelerating the transition toward sustainable, human-relevant toxicology.
Together, the two companies are charting a future where safety testing becomes faster, more predictive, and fundamentally more humane—a vision aligned with both scientific progress and societal responsibility.
