Organ-on-chip Platforms in Modern Drug Development and Testing

Practical workflows, common organ models, and the evolving regulatory landscape.

Organ-on-chip (OOC) platforms are microfluidic systems based on human cells that recreate organ-level structure and function to produce physiologically relevant data. This guide explains the most used organ chips and their importance, how OOCs fit into drug development stages, and the regulatory changes that are making OOC increasingly adopted.

Differences between organoids, organ-on-chip and microphysiological systems

When exploring the emerging field of microphysiological systems, it can be challenging to navigate the terminology and understand the essential distinctions. Advanced in vitro modeling includes several complementary technologies, such as organoids, organ-on-chip (OOC) systems, and microphysiological systems (MPS), each differing in biological and engineering complexity, and their applications.

Organoids

Organoids are 3D, self-organized, stem-cell–derived mini-organs that arise from intrinsic developmental programs. They can be generated from induced pluripotent stem cells (iPSCs), embryonic stem cells, or adult stem cells, and often exhibit tissue-specific architectures, such as the cortical layers found in brain organoids. Organoids offer high biological complexity but typically have limited perfusion and lack mechanical stimulation.

Organoids are frequently confused with spheroids and tumoroids, although these 3D models represent different levels of complexity and serve distinct experimental purposes:

Spheroids are simple 3D aggregates composed of one or more cell types that self-assemble under low-adhesion conditions (e.g., hanging-drop plates, ultra-low attachment plates, or spinner cultures). They are widely used in high-throughput drug screening.
Tumoroids are patient-derived tumor organoids, a specialized subset of organoids generated from primary tumor tissue. They preserve tumor heterogeneity, genetic mutations, and, in some cases, microenvironmental features, making them valuable for precision oncology [1].

Learn more about organoid modeling, and how to move from static to dynamic culture.

Organ-on-Chip

Organ-on-chip devices are microengineered systems that combine human cells, controlled microfluidic flow, and mechanical cues to reproduce organ-level structure, function, and microenvironmental forces. Compared to organoids, OOCs rely heavily on flow control for nutrient delivery, waste removal, and the replication of dynamic physiological conditions such as shear stress, breathing motions, or peristalsis.

Microphysiological Systems

Microphysiological systems (MPS) are a collective term encompassing any in vitro models that reproduce human physiological functions at the tissue, organ, or multi-organ scale. MPS include:

organ-on-chip systems
organoids
perfused tumoroids or spheroids
synthetic bioprinted microtissues
static transwell co-cultures
multi-organ “body-on-chip” platforms

Complexity Hierarchy of MPS

Advanced in vitro models span a broad spectrum of complexity, starting with basic 3D cultures and progressing toward dynamic, microengineered systems that more closely replicate human physiology.

Spheroids → Tumoroids → Organoids → Organ-on-Chip → Full Microphysiological Systems

complexity hierarchy of ooac — *Figure 2 Complexity of in vitro systems*

Feature	Spheroids	Tumoroids	Organoids	Organ-on-Chip
3D Structure	Simple sphere	Patient-derived structure	Organ-like	Engineered microenvironment
Cell Source	Cell lines / mixed	Primary tumor	Stem cells	Primary or iPSC-derived
Architecture	Minimal	Tumor-specific	Tissue-specific	Device-defined
Perfusion	❌ None	❌ None	❌ None (unless hybrid)	✅ Controlled
Mechanical Forces	❌ None	❌ None	❌ None	✅ Physiological
Drug Testing	Medium-throughput	Patient-specific	Disease-specific	Mechanistic PK/PD
Shear Stress	❌ None	❌ None	❌ Minimal	Fully tunable
Personalization	Low	Very high	High	Medium–high
Reproducibility	Good	Medium	Medium–high	High

Limitations of Animal Models in Drug Development and Testing

Drug development continues to face a well-known translation gap, where promising preclinical results in rodent models fail to reproduce in human clinical trials. Most failures occur due to insufficient efficacy or unexpected toxicity when candidates move from animal studies into human testing [3]. Moreover, the FDA’s 2025 roadmap on reducing animal testing also emphasizes that animal-based data have been particularly poor predictors of success in areas such as Alzheimer’s disease and inflammatory disorders [4].

A key limitation is that a compound may appear safe in animals yet cause serious harm in humans, because metabolism, immune responses, receptor biology, and tissue susceptibility differ markedly between species. A well-documented example is fialuridine (FIAU), an antiviral compound that passed animal testing but caused fatal hepatic failure and lactic acidosis in human trials [5].

The Opposite Scenario: False Negatives

Conversely, the reverse problem also occurs, potentially effective drugs may be incorrectly rejected due to toxicity in a particular animal species. A classic case is penicillin, which is safe and life-saving for humans but can be lethal to guinea pigs [6]. These “false negatives” illustrate the inherent risk of making human safety decisions based solely on animal responses.

Modeling Human Disease Mechanisms

Beyond safety assessments, animal models also influence our early mechanistic understanding of diseases, which in turn shapes target identification and drug discovery strategies. However, when human disease biology differs substantially from that observed in animals, entire discovery programs may be built on misleading assumptions. A notable case is Alzheimer’s disease (AD): decades of mouse research have produced mechanistic hypotheses that do not consistently translate to clinical benefit [2]. Recent research reviews argue that current mouse models frequently fail to capture the clinical heterogeneity of Alzheimer’s disease, and that many models overrepresent familial mutation-driven mechanisms compared with the predominantly irregular disease burden in humans [7]. 

Animal Model systems Alzheimers disease — Figure 3 Illustration of models for Alzheimers disease and comparison8

Why Organ-on-a-Chip Technology Offers Improved Human Relevance for Drug Testing

Recent analyses of the OOAC field show that single- and multi-organ chips can model complex diseases, reproduce aspects of clinical drug responses, and capture human-specific biology that traditional models miss[9]. However, there are several challenges that must be addressed with full regulatory and industry adoption, as this transition is now following supportive policy changes such as the FDA Modernization Act 2.0 (2022), the first U.S. legislation enabling non-animal methods to be used in place of mandatory animal testing [10].

OOCs provide engineered microenvironments that cannot be achieved in static 2D culture systems. Unlike dish-based assays, Organ-on-a-chips can maintain physiological conditions that are essential for realistic organ function, including:

3D architecture or 3D-like organized co-cultures
Continuous perfusion for nutrient delivery, waste removal, and tissue-level pharmacokinetics
Controlled biochemical gradients (oxygen, cytokines, drugs)
Functional tissue-tissue interfaces (such as epithelium–endothelium)
Dynamic mechanical forces (shear stress, mechanical compression/stretch)

Because OOCs utilize human cells under physiologically relevant mechanical and biochemical cues, they aim to overcome key failure points of animal testing, such as species-specific biology.

Some of the clearest demonstrations of the “human advantage” of OOAC/MPS systems come from oncology and immuno-oncology. Here, the objective is not only toxicity testing but also predicting patient-specific therapy responses. Recent reviews highlight how microphysiological systems can recreate elements of the human tumor microenvironment, including vasculature, stromal interactions, and immune components, to evaluate immunotherapies and tumor-immune dynamics in ways that are impractical in animal models or static cultures [11].

Organ-on-Chip in the Drug Development and Testing Pipeline

Drug development is a long, expensive, and failure-prone process, as illustrated in the figure below, which outlines the traditional pipeline from target validation through clinical testing and final approval. At each stage, thousands of drug candidates are progressively filtered down to only a handful that enter human trials, and only a few that reach the market. As pharmaceutical R&D shifts toward human-relevant preclinical methods, organ-on-a-chip systems are becoming increasingly integrated across multiple stages of the drug development pipeline. Their value lies in combining human biology and real-time analytics, making them uniquely suited to address long-standing translational challenges. OOCs can reproduce human-specific responses in ADME, toxicity, and disease modeling that traditional animal studies often miss [9].

drug testing pipeline in ooac — Figure 4 Drug testing pipeline

Early Discovery: Disease Modelling and Target Identification

In the earliest stages of drug development, researchers seek to understand disease mechanisms and identify tractable drug targets. OOCs enable these insights by modeling human pathophysiology under controlled microenvironmental conditions.

Added values of OOCs in this stage are the ability to recreate disease-specific cues, such as inflammation, hypoxia, mechanical stress, or dysregulated barrier function. Human-centric models also better reflect patient heterogeneity, especially when seeded with iPSC-derived or primary patient cells. For example, tumor-on-chip models replicate the 3D tumor microenvironment, including metastatic behavior and drug resistance mechanisms, and diseases that require precise mechanistic responses from humans, such as inflammatory bowel disease (IBD), barrier dysfunctions and microbiome interaction, can be modelled using gut-on-chip technology.

Lead Optimization: In Vitro ADME and Pharmacokinetics

Once a target is identified, lead compounds must be screened for absorption, distribution, metabolism, and excretion (ADME). This is where multi-organ OOC platforms stand out.

They support linked organ systems, such as gut → liver → kidney, which recreate human-like PK trajectories.
Controlled flow allows precise modulation of drug exposure, enabling more accurate prediction of concentration–time curves.
Organ-on-chips can produce human-relevant metrics like metabolite profiling that correlate with clinical findings.

For instance, liver-kidney microfluidic loops simulate biliary clearance and renal excretion. Several studies have demonstrated that OOCs can reproduce human PK behavior more accurately than rodent models, including prediction of oral absorption rates and drug–drug interactions [9].

Learn more about liver-kidney axis and how this loop can be created with microfluidics.

Or how the kidney organoids can be vascularized on chip.

Preclinical Safety Assessment: Toxicology and Off-Target Effects

Toxicity remains the most common cause of clinical trial failure. OOC platforms excel at flagging human-specific toxic effects before animal or clinical testing. They permit organ-specific toxicity assays under human cell conditions. For example, a liver chip with 3D lobule architecture has been used to study drug–drug interaction toxicity during liver metabolism. Multi-organ systems can simultaneously monitor on-target and off-target toxicity: one design integrated liver and heart chips with biosensors to show that a metabolized cancer drug caused both hepatotoxicity and cardiotoxicity. Such chip tests have correctly identified toxic liabilities not seen in animal studies. Importantly, human OOCs can reveal adverse effects that animals miss (e.g. clinically observed cardiac or renal toxicity). Thus, OOCs are envisioned as tools for late preclinical safety evaluation, screening out candidates with human-specific toxicity before clinical trials

Translational PK/PD and Precision Medicine

OOCs are especially promising for predicting individual patient responses, supporting the emerging field of personalized medicine. They allow the use of patient-derived cells, including tumor biopsies and ex-vivo microtissue tests. These systems can be used to test multiple therapeutic regimens ex vivo. For instance, the SliceChip setup permitted longterm culture of murine pancreatic islets, with comparable glucose kinetics and low shear stress in both chambers and allowed combined extracellular electrophysiology and insulin secretion analysis. The controlled perfusion enabled testing of glucose and aminoacid stimuli, making the system relevant for diabetes drug development.

Another use case of functional assays on organ-on-chip is cardiac organ-on-chip assay with Aria and live-imaging:

Read further about the possibility of multi-parametric functional assay on cardiac OOCs

Regulatory and Policy Landscape for Organ-on-Chip Adoption in Drug Development

The global regulatory environment is undergoing a historic shift toward human-relevant, non-animal testing methods, and OOC platforms sit at the center of this transformation. While OOCs are not yet a full replacement for animal studies, the legal and policy landscape now strongly encourages their integration into the drug development and testing pipeline.

United States: Policy Momentum Toward Non-Animal Testing

Recent U.S. legislation and FDA actions have accelerated the transition toward MPS, including OOCs. The FDA Modernization Act 2.0, signed on December 29, 2022, removes the decades-old requirement that drug sponsors rely on animal testing to meet preclinical safety standards [12]. Under this law, New Approach Methodologies (NAMs), including OOCs, organoids, iPSC-derived tissues, and computational models, are explicitly permitted for generating preclinical safety and efficacy data. To implement the Act, the FDA established the NAMs Program in 2022, dedicating staff, infrastructure, and funding to evaluate and qualify non-animal technologies.

The Innovative Science and Technology Approaches for New Drugs (ISTAND) program is designed to qualify novel methodologies for specific regulatory contexts of use. One of the actions in 2024 was the acceptance of organ-on-chip technology designed to predict drug-induced liver injury (DILI)[13].

In 2025, the FDA publicly announced a multi-year plan to phase out animal testing requirements for monoclonal antibodies and other therapeutics, explicitly stating that:

“Advanced cell-based models, organoids, and organ-on-a-chip systems will be incorporated as scientifically justified alternatives within preclinical development.”

—FDA Press Release, 2025[14]

This roadmap provides a stepwise strategy for sponsors to integrate OOCs as part of preclinical packages, beginning with context-of-use-specific qualification, cross-validation with existing assays, and increased submission of OOC-generated safety data.

European Union: Accelerating the Shift to Non-Animal Approaches

The EU has long been a leader in advancing ethical and scientifically robust alternatives to animal testing. Regulatory bodies increasingly promote the integration of OOCs, organoids, and MPS as part of a long-term strategy for phasing out animal use in research and safety assessment. European legislation mandates the Replacement, Reduction, and Refinement (3Rs) of animal experiments. This legal foundation underpins EU-wide initiatives to incorporate New Approach Methodologies, including organ-on-chip systems.

In 2021, the European Parliament passed a resolution calling for a coordinated, EU-level roadmap to eliminate animal testing in science, agriculture, and regulatory safety.

This directive urged rapid adoption of:

microphysiological systems
organoids
in vitro NAMs
advanced computational modeling

In late 2023, the European Medicines Agency (EMA) issued a concept paper proposing updates to regulatory guidelines for safety testing and 3Rs methods. The document explicitly mentions OOCs and organoids as candidate platforms for NAM-based submissions.

EMA further supports:

Scientific Advice meetings to guide NAM developers
Voluntary qualification pathways for MPS and OOC assays
Regulatory alignment with international agencies to encourage global acceptance

In 2025, the European Federation of Pharmaceutical Industries and Associations (EFPIA) published a strategic document recommending:

regulatory incentives for NAM adoption
harmonization between EMA, FDA, and PMDA
updated guidelines to accelerate the transition away from animal testing

Future outlook

Looking ahead, the organ-on-chip field is undergoing a period of meaningful transformation. However, it is essential to highlight that neither the 3Rs framework nor current legislation implies that animal models are being fully replaced today in the long drug development journey. OOCs and other NAMs represent powerful yet complementary tools that are already being used alongside animal models in drug development. Regulatory momentum and technological maturity are now converging to make broader OOC adoption increasingly feasible.

With pressure-based flow systems expertise, we see daily how organ-on-chip success depends on more than engineering excellence alone. It requires multi-organ integration and automation, that is supported through consistent collaboration across pharma, academic researchers, regulatory agencies, and technology providers. This collaborative ecosystem will determine how quickly OOCs evolve from innovative research devices into standard components of preclinical workflows.

One major force shaping the future is the transition toward whole-body microphysiological systems. Connecting gut, liver, kidney, vasculature, and immune modules enables drug ADME to be studied in a way that better reflects human systemic responses. At the same time, the next decade surely will bring a decisive push toward automation and industrialization. Organ-on-a-chip perfusion, real-time monitoring, and standardized chip formats will enable reproducible, GLP-ready workflows. By reducing operational complexity, automation lowers the barriers for pharmaceutical teams to incorporate OOCs into discovery, ADME testing, and preclinical toxicology, delivering the predictability and robustness required for pharmaceutical adoption.

Finally, perhaps the most important driver is regulatory adoption. The FDA Modernization Act 2.0, the NAMs Program, ISTAND, and the parallel developments within the EMA mark the formal beginning of a new regulatory era. These policies do not eliminate animal testing, but they establish clear pathways for including OOC data in submissions and for validating chip-based assays for defined contexts of use.

In this evolving landscape, advice for industry and academia is clear: begin integrating OOCs in targeted areas. Build internal expertise, generate comparative datasets, and participate in validation efforts. The future of drug development will not be shaped by any single stakeholder but by collective alignment between biologists, engineers, regulators, and technology developers who share the goal of reducing reliance on animal models while increasing human relevance.

References

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[2] V. Carvalho, M. Bañobre-López, G. Minas, S. F. C. F. Teixeira, R. Lima, and R. O. Rodrigues, “The integration of spheroids and organoids into organ-on-a-chip platforms for tumour research: A review,” Bioprinting, vol. 27, p. e00224, Aug. 2022, doi: 10.1016/j.bprint.2022.e00224.

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[9] D. E. Ingber, “Human organs-on-chips for disease modelling, drug development and personalized medicine,” Nat Rev Genet, vol. 23, no. 8, pp. 467–491, Aug. 2022, doi: 10.1038/s41576-022-00466-9.

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[13] C. for D. E. and Research, “FDA’s ISTAND Pilot Program accepts a submission of first organ-on-a-chip technology designed to predict human drug-induced liver injury (DILI),” FDA, Sep. 2025, Accessed: Feb. 09, 2026. [Online]. Available: https://www.fda.gov/drugs/drug-safety-and-availability/fdas-istand-pilot-program-accepts-submission-first-organ-chip-technology-designed-predict-human-drug

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