Experimental Pathology Laboratories, Inc., which uses the trademark EPL, is a toxicologic pathology specialist in Sterling, Virginia. The company states that it was "founded in 1971" and is "a private, employee-owned U.S. company,"[S1] and describes its services as toxicologic pathology evaluation and consultation.[S1] No in-life study service was found on the pages reviewed; that is an absence in those pages, not a finding that EPL does not house or dose animals. The reviewed pages describe evaluation of tissue from studies conducted elsewhere. This profile summarizes the services, stated compliance information, and company facts most relevant to US sponsors.
Services relevant to US drug developers
Pathology and peer review
Pathology is the core line, covering histopathology evaluation, pathology peer review, Pathology Working Groups, carcinogenicity and chronic study pathology, transmission electron microscopy and research animal model support.[S3] The company states that its "board-certified pathologists bring deep expertise across all organ systems and most animal species commonly used in discovery, investigative, and preclinical safety assessment studies,"[S3] naming fourteen organ and therapeutic systems including cardiovascular, dermal, developmental immunotoxicology, hepatobiliary, lymphoid, male and female reproductive, nervous system, ocular, renal, respiratory and skeletomuscular pathology.[S3] For carcinogenicity work it names "traditional rodent bioassays and the rasH2 transgenic mouse model."[S3] Peer review and Pathology Working Groups matter to sponsors because sponsors commissioning peer review or a Pathology Working Group should define reviewer independence, scope, reconciliation and reporting in the protocol; those terms are easier to agree before the study than after a finding is disputed from the one that ran the study.
Histology, imaging, toxicology support, and data services
The company states that "EPL's histology labs provide everything from routine tissue processing and staining to advanced dissection and multiplex immunolabeling,"[S4] covering routine haematoxylin and eosin staining, immunohistochemistry and immunofluorescence, specialty histochemical stains, aquatic animal and avian histology, and necropsy.[S4] Imaging services cover whole slide scanning, image analysis and stereology.[S7] Transmission electron microscopy is performed at a named partner facility, the Bioscience Electron Microscopy Laboratory at the University of Connecticut, using "a JEOL 1400 transmission electron microscope, equipped with an AMT Nanosprint 43M Mark II CMOS camera."[S3] Toxicology support is offered jointly with a named partner: the company states that "EPL and Aclairo's board-certified experts bring deep expertise in toxicology, with several team members dual-certified in both pathology and toxicology."[S5] The nature of the relationship between the two organizations is not described on the site. Data services cover SEND dataset generation, offered since 2017,[S6] with the company stating that "from SEND dataset generation to custom formatting for unique sponsor needs, we ensure your data is accurate, validated, and tailored for its intended use."[S6]
Regulatory ecotoxicology assays
EPL offers histopathology for regulatory endocrine disruption assays. The company states that it "played a key role in the design and validation of original EPA and OECD Tier 1 and Tier 2 assays for endocrine disruption,"[S4] and names the Fish Short-Term Reproduction Assay, the Amphibian Metamorphosis Assay, the Medaka Extended One Generation Reproduction Test, the Larval Amphibian Growth and Development Assay and an avian two-generation toxicity test in Japanese quail.[S4] This is ecotoxicology rather than pharmaceutical safety work, and is relevant to agrochemical and chemical sponsors more than to drug developers.
Quality and compliance (as stated by the company)
GLP. The company states that it "ensures your studies align with Good Laboratory Practice (GLP) guidelines as defined by the US FDA, US EPA, OECD, and other international regulatory authorities,"[S3] and describes its research animal model pathology support and its electron microscopy work as GLP-compliant.[S3] The company names US FDA, US EPA, OECD in its GLP statement.[S3] GLP compliance is determined study by study under the applicable regulation, so sponsors should confirm in the protocol which regulation their study will follow and that the final report will carry the study director's compliance statement and the quality assurance unit's statement.[R2] No GCLP or CLIA statement was found, and no AAALAC accreditation, USDA registration, OLAW Animal Welfare Assurance or IACUC statement appears on the pages reviewed. That absence is consistent with a laboratory that receives tissue rather than housing animals; it is not a gap in the same sense it would be for an in-life CRO. AAALAC International accreditation is a voluntary evaluation of an institution's animal care and use program, re-evaluated every three years,[R3] and USDA registration and an OLAW Animal Welfare Assurance relate to the Animal Welfare Act and the PHS Policy respectively;[R4][R5] none of these establishes GLP compliance, which applies to individual studies.[R2] FDA does not approve or certify laboratories; registration with FDA does not denote approval.[R6]
Company facts
Legal name
Experimental Pathology Laboratories, Inc. (EPL)[S1]
Headquarters
45600 Terminal Drive, Sterling, VA 20166, United States[S1]
Sterling, VA (headquarters) and an EPL-Boston, Massachusetts operation; no street address is published for the Boston site[S1][S8]
Employees
Not published
Service scope
Pathology, peer review and Pathology Working Groups, histology, imaging, toxicology support with a partner, data services. No in-life study, safety pharmacology, DMPK or bioanalysis service statement was found on the pages reviewed; this is not a finding that EPL cannot provide or arrange those services[S3][S4][S5][S7]
Carcinogenicity pathology
Traditional rodent bioassays and the rasH2 transgenic mouse model[S3]
Electron microscopy
Performed at the Bioscience Electron Microscopy Laboratory, University of Connecticut, on a JEOL 1400 instrument[S3]
Toxicology partner
Delivered jointly with Aclairo; the relationship is not described on the site[S5]
FDA ? "Is It Really FDA Approved?" (FDA does not approve health care providers, including laboratories; registration does not denote approval); FDA Compliance Program 7348.808 (GLP inspections of nonclinical laboratories). https://www.fda.gov/consumers/consumer-updates/it-really-fda-approved (accessed 2026-09-03)
3 Recommended Contract Research Organizations for Non-Clinical Studies
— by Target goal and Expertise
In drug discovery, the quality and efficiency of non-clinical studies have a direct impact on clinical success rates, development costs, and overall length of time required in R&D.
In recent years, there has been more demand for clinically relevant data, globally accepted reliability, and accurate early-stage screening.
Thus, it is more important than ever to select the right CRO (Contract Research Organization) for strategic approach.
In this article, we highlight three CROs with proven technical capabilities, expertise, and long standing track records. These are our TOP 3 choices based on their capabilities and the specific target goals of the researchers for their non-clinical studies.
Pharmacology (Efficacy) Studies Replicate unknown pathological models and Discovery to clinically oriented drug evaluation
SMC Laboratories, Inc.
Reference: SMC Laboratories, Inc. official website (https://www.smccro-lab.com/jp/)
SMC Laboratories, Inc. has established a disease models using patented mouse technologies.
The company has established proprietary pathological models—particularly in liver disease and fibrosis—and continues to expand their approach across a wide range of models in cancer, inflammation, and metabolic diseases.
From exploratory research to clinically oriented efficacy evaluation, SMC offers customized study designs, dosing strategies, and evaluation analysis tailored to each project.
Their collaborative approach allows researchers to discuss and refine study plans together with SMC’s expert scientists.
With flexible small-scale study options and strong technical support, SMC Laboratories, Inc. is an ideal partner for start-ups, biotech ventures, and academic institutions alike.
Safety Studies Comprehensive Safety Evaluation for FIH Applications
Labcorp Holdings Inc. (Labcorp Drug Development)
Reference: Labcorp Holdings Inc. official website (https://jp.labcorp.com/)
Labcorp Holdings Inc. provides a fully integrated GLP testing system aligned with international regulatory standards, including FDA, EMA, and PMDA requirements.
All studies are conducted under ICH-compliant quality assurance, making it ready for data submission.
The company has extensive expertise in long-term toxicity studies such as Segment I–III reproductive and carcinogenicity studies, as well as 2-year chronic toxicity assessments.
Labcorp Holdings Inc.’s comprehensive approach enables sponsors to efficiently outsource the entire preclinical package from toxicology, toxicokinetic (TK), and safety pharmacology study design to execution. This accelerates a path to First-in-Human (FIH) trials.
For most of the global drug developers, this all-in-one service structure minimizes cost, risk, and expedite the time before advancing to clinical phase.
Pharmacokinetic (PK/PD) Studies High-Precision Bioanalysis for Clinically Predictive PK/PD Evaluation
PhoenixBio Co., Ltd.
Source: PhoenixBio Co., Ltd. Official Website (https://phoenixbio.co.jp/)
PhoenixBio Co., Ltd. offers pharmacokinetic and hepatic metabolism studies using their proprietary PXB-mouse®, a humanized-liver chimeric mouse model. This platform enables the acquisition of data with high clinical correlation in ADME, drug–to–drug interaction studies, bridging the gap between preclinical and clinical stages.
With advanced LC-MS/MS-based bioanalysis, PhoenixBio Co., Ltd. provides a seamless workflow from plasma concentration measurement and metabolite identification to quantitative validation.
The company offers an integrated evaluation analysis covering pharmacokinetics, hepatotoxicity, and safety with flexibility to accommodate complex modalities such as oligonucleotide and middle-molecule therapeutics.
For compounds where hepatic metabolism is a development bottleneck—or where quantitative, reproducible exposure data are critical—PhoenixBio Co., Ltd. delivers unmatched analytical precision and consistency.
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