CAR T cell therapy has emerged as one of the most promising immunotherapies for blood cancers like leukemia, offering patients a tailored assault on malignant cells by reprogramming their own immune systems. Despite impressive clinical successes, a significant fraction of patients relapse, and many suffer serious adverse effects. Scientists have long grappled with the difficulty of accurately predicting patient responses or refining these therapies due to the limitations of current preclinical testing models. Conventional two-dimensional cell cultures often fail to replicate the intricate biological environments where cancer and immune cells interact, while animal models are labor-intensive, costly, and sometimes poorly predictive of human outcomes.

This innovative device, the size of a standard microscope slide, takes a giant leap forward by replicating the three-dimensional architecture and immunological complexity of the human bone marrow — the primary niche where leukemia cells thrive. Crucially, it incorporates not just the physical structure but also a functioning human immune system, enabling real-time observations of CAR T cell dynamics in an authentic microenvironment. The chip’s design includes three distinct bone marrow regions: blood vessels, the surrounding marrow cavity, and the outer bone lining, all populated with patient-derived bone marrow cells that self-organize and secrete key extracellular matrix components such as collagen, fibronectin, and laminin. This self-assembly recreates the native tissue architecture and its multifaceted immune ecosystem.

The technical sophistication of this “bone marrow on a chip” permits the formation of vascularized niches that maintain realistic immune cell trafficking and interactions. This is a notable departure from traditional models that lack vascular complexity, often resulting in oversimplified or inaccurate assessments of therapeutic action. Using high-resolution imaging and advanced microscopy, the research team tracked individual CAR T cells as they navigated the microvascular networks, detected leukemia targets, and executed cytotoxic attacks. They observed with unprecedented clarity how CAR T cells slow their motility upon encountering malignant cells, facilitating direct engagement and destruction — a dynamic process previously difficult to capture in vitro or in animal models.

Beyond direct antitumor activity, the study revealed a fascinating “bystander effect,” where engineered CAR T cells stimulate non-targeted endogenous immune cells within the device. This interplay may shed light on both the therapeutic potentiation and adverse inflammatory side effects observed in patients, pointing to new avenues for modulating immune responses to maximize efficacy while minimizing toxicity. The chip also proved capable of modeling clinical scenarios including complete remission, resistance to therapy, and relapse, offering a powerful platform to study mechanisms underlying these varied outcomes.

A remarkable advantage of this platform is its scalability and time efficiency. While traditional animal models can take months to establish and require complex protocols, the leukemia-on-a-chip system can be assembled within half a day and supports experimental assays extending up to two weeks. This rapid turnaround opens the door for personalized medicine applications, where patient-specific bone marrow samples can be cultured and tested against multiple CAR T cell designs before selecting the optimal therapeutic approach.

The research team demonstrated that next-generation “fourth generation” CAR T cells, which incorporate enhanced engineering features for improved persistence and potency, outperformed earlier versions at lower dosages within the chip environment. This suggests the device’s utility in optimizing dose regimens and therapy formulations, potentially reducing toxic side effects while maintaining efficacy. Overall, this bioengineered platform represents an integrated, immunocompetent preclinical trial tool that bridges an important gap between bench research and patient care.

As regulatory agencies such as the FDA announce plans to phase out animal testing for drug safety evaluation, the timing of this breakthrough could not be more significant. By providing a physiologically relevant, animal-free model for immunotherapy testing, the leukemia-on-a-chip aligns with the drive toward humane, cost-effective, and predictive research alternatives. The device’s capacity to model dynamic, systemic immune responses within a controlled setting enables extensive mechanistic studies that can guide rational design of novel immunotherapies for leukemia and potentially other cancers.

This multidisciplinary collaboration underscores the power of combining mechanical engineering, microfluidics, cellular biology, and immunology to tackle complex challenges in cancer research. By harnessing patient-derived cells and reproducing the intricacies of the leukemia niche, researchers now have a cutting-edge tool to dissect immunotherapy resistance, identify biomarkers of response, and fine-tune treatments prior to clinical trials. The prospect that clinicians might one day leverage this technology to personalize therapy selection, improving outcomes and reducing side effects, heralds a new era in precision oncology.

The implications extend beyond leukemia alone. This platform’s modular design and ability to mimic tumor-immune interactions pave the way for similar “organ-on-a-chip” models targeting solid tumors and other hematologic malignancies. The convergence of bioengineering and immunotherapy now promises to accelerate the translation of laboratory insights into real-world cures in a timeframe and cost structure previously unimaginable.

In sum, the bioengineered leukemia-on-a-chip stands as a testament to innovation at the interface of engineering and medicine. It is poised to become a pivotal asset in the battle against cancer, not only enhancing our understanding of CAR T cell behavior in physiologically relevant contexts but also empowering clinicians and scientists to forge truly personalized treatment regimens. As this technology matures, it offers hope that the next wave of immunotherapies will be smarter, safer, and more effective, transforming lives for patients facing leukemia across the globe.

Subject of Research: Cells

Article Title: Bioengineered immunocompetent preclinical trial-on-chip tool enables screening of CAR T cell therapy for leukaemia

News Publication Date: 1-Jul-2025

Web References:

• Original article DOI: 10.1038/s41551-025-01428-2
• University of Pennsylvania Perelman School of Medicine: https://www.med.upenn.edu/
• FDA announcement on animal testing phase-out: https://www.fda.gov/news-events/press-announcements/fda-announces-plan-phase-out-animal-testing-requirement-monoclonal-antibodies-and-other-drugs

Image Credits: NYU Tandon Applied Micro-Bioengineering Laboratory/Courtesy of Weiqiang Chen

Keywords: Chimeric antigen receptor therapy, Blood cancer, Leukemia, Cancer treatments, Cancer immunotherapy, Biomedical engineering

The $400,000 Merkin Prize, shared among these four innovators, acknowledges their groundbreaking contributions to biomedical technology that have significantly reshaped cancer treatment paradigms. More than just a breakthrough in oncology, CAR T-cell therapy represents a paradigm shift in precision medicine that harnesses the power of the immune system to fight disease. Patients’ T cells are extracted, genetically engineered in a laboratory environment to express a synthetic receptor targeting cancer-specific proteins, then expanded and infused back into the body. This engineered cellular response equips the immune system to hunt down and destroy tumor cells with formidable specificity and potency.

Richard Merkin, M.D., the prize’s namesake and founder of Heritage Provider Network, emphasizes the profound impact of this technology: “The development of CAR T-cell therapy is a defining moment in biomedical history, an extraordinary example of how foundational scientific insights can be translated into lifesaving therapies. Honoring these scientists underscores the magnitude of their impact on cancer and beyond, positioning us on the cusp of curing millions.”

Administered by the Broad Institute, the Merkin Prize rewards technologies that have meaningfully advanced human health. A rigorous selection process by a committee of distinguished scientific leaders from the academic and industry sectors across the US and Europe vetted this year’s finalists. The winners will be formally recognized in a ceremony later this year, celebrating a milestone in immunotherapy development with significant implications for future medical innovations.

The concept of redirecting the immune system to target cancer thoughtfully harnesses immunological defense mechanisms but faced significant challenges in achieving efficacy and safety. CAR T-cell therapy provides an elegant solution built on genetic engineering principles. By introducing chimeric antigen receptors—synthetic molecules that combine tumor antigen recognition and T-cell activation capabilities—researchers enable T cells to identify and kill cancer cells expressing specific proteins such as CD19, a hallmark of certain blood cancers. These re-engineered T cells demonstrate unparalleled specificity and cytotoxic activity against tumor targets.

Key to this technological leap was Michel Sadelain’s work in the 1990s, then at Memorial Sloan Kettering Cancer Center, where he crafted CARs by fusing antibody fragments with T-cell receptor signaling domains. Sadelain’s innovation laid the molecular groundwork showing that synthetic CAR T cells could provoke a robust immune response upon encountering cancer antigens. His early demonstration of targeting the CD19 protein remains foundational to today’s commercial CAR T-cell therapies.

The challenge of cellular persistence in vivo was addressed by Carl June’s pioneering research at the University of Pennsylvania. In the mid-1990s, June demonstrated that genetically engineered T cells could survive for extended periods within patients, initially studying resistance to HIV infection. This persistence is fundamental, as chronic engagement and elimination of cancer require engineered T cells to remain active within the body for months or years, enabling sustained tumor surveillance and destruction.

Turning these scientific insights into a scalable, clinically viable therapy demanded a remarkable collaborative effort. June and Bruce Levine optimized methods for harvesting, genetically modifying, and expanding patient T cells at therapeutic scale, while Sadelain and Isabelle Rivière refined CAR construct design by incorporating “costimulatory” domains—molecular signals boosting T-cell activation and longevity. This boosting signal enhanced the efficacy and durability of CAR T-cell responses and is now standard in all approved CAR therapies.

From the early 2000s, these teams transitioned their work into clinical applications. The first leukemia patient treatment using personalized CAR T cells occurred in 2007, with Rivière and Sadelain’s team publishing their manufacturing protocols shortly thereafter. Their technology was licensed to Juno Therapeutics, which Bristol Myers Squibb later acquired. Parallel efforts led to FDA approvals in 2017 for CAR T-cell therapies developed by Novartis and Kite Pharmaceuticals, firmly establishing CAR T therapy among frontline treatments for hematological malignancies.

Rivière recalls the “eureka” moment when their first patient treated with CD19-targeted CAR T cells achieved an undetectable leukemia state just weeks post-infusion, a profound testament to the therapy’s curative potential. Similarly, Levine reflected on early trial data showcasing dramatic tumor regression, providing hope to patients facing otherwise fatal relapsed or refractory blood cancers. These clinical successes validated CAR T-cell therapy as a transformative advance in oncology.

Since the first FDA approval, seven CAR T-cell products have emerged addressing multiple blood cancers, including acute lymphoblastic leukemia, large B-cell lymphoma, and multiple myeloma. While these products have been optimized, they all build on the foundational designs and manufacturing strategies developed by June, Levine, Rivière, and Sadelain. The therapy’s demonstrated success has sparked ongoing research into broadening CAR T technology’s applicability beyond oncology.

Clinical trials are now exploring CAR T cells as treatments for autoimmune diseases such as systemic lupus erythematosus, where selective targeting of autoreactive immune cells offers potential to induce remission without global immunosuppression. Additionally, researchers are investigating therapeutic possibilities in infectious diseases, tissue fibrosis, and even age-related degenerative conditions, leveraging the modular nature of CAR designs to target diverse pathological proteins.

Looking forward, advances in CAR engineering—such as next-generation receptors enabling nuanced modulation of T-cell activity—and improvements in cell manufacturing scalability promise to expand access and efficacy. Novel generation CAR T cells aim to overcome current limitations including toxicity, antigen escape, and complex production logistics. As these advances mature, CAR T-cell immunotherapy stands poised to revolutionize precision medicine worldwide, offering hope to millions across a spectrum of life-threatening diseases.

The remarkable journey from molecular design to lifesaving therapy epitomizes the synergy between innovative science, engineering, and clinical translation. The Merkin Prize’s recognition of June, Levine, Rivière, and Sadelain honors not only their scientific brilliance but also their enduring impact on human health—a testament to the remarkable power of harnessing the immune system in the fight against disease.

Subject of Research: Chimeric Antigen Receptor (CAR) T-cell Therapy Development and Clinical Applications

Article Title: Trailblazers Awarded 2025 Merkin Prize for Pioneering CAR T-cell Therapy that Revolutionized Cancer Treatment

News Publication Date: 2025

Web References:
– https://mediasvc.eurekalert.org/Api/v1/Multimedia/9bf29010-73a2-42e7-8151-f17caaf7ac0b/Rendition/low-res/Content/Public
– Broad Institute (https://www.broadinstitute.org)
– University of Pennsylvania Perelman School of Medicine (https://www.med.upenn.edu)
– Memorial Sloan Kettering Cancer Center (https://www.mskcc.org)

Image Credits: University of Pennsylvania Perelman School of Medicine, Columbia University Irving Medical Center

Keywords: CAR T-cell therapy, cancer immunotherapy, chimeric antigen receptor, personalized medicine, leukemia treatment, lymphoma therapy, blood cancers, immuno-oncology, cellular immunotherapy, genetic engineering, precision medicine, biomedical innovation