• CAR NK cell therapy is a novel immunotherapy made from natural killer (NK) cells engineered to better recognize and eliminate cancer cells 

• At UT MD Anderson, CAR NK cell therapies are created from NK cells collected from donated umbilical cord blood  

• MD Anderson researchers identified a small population of immature NK cells associated with poorer treatment outcomes 

• These immature cells can pick up cancer proteins through a process known as trogocytosis and become false targets, causing therapeutic NK cells to attack one another 

• Removing the immature cells before manufacturing improved CAR NK cell function and improved tumor control in preclinical models 

HOUSTON, JULY 29, 2026 ― The composition of donor cord blood may play a critical role in the success of chimeric antigen receptor (CAR) natural killer (NK) cell therapies. A small population of immature NK cells present in donor cord blood can undermine the activity of CAR NK cell therapy by redirecting potent immune cells away from tumors and causing them to attack one another, according to researchers from The University of Texas MD Anderson Cancer Center.  

The study, published in Cancer Cell, identifies a previously unrecognized mechanism of CAR NK cell dysfunction and offers a practical strategy to improve the potency and consistency of future off-the-shelf NK cell therapies. Researchers found that cord blood units enriched for mature NK cells were linked to stronger treatment responses and better patient outcomes, while higher levels of immature NK cells were associated with reduced effectiveness. The team discovered that these immature cells actively disrupted the function of more potent CAR NK cells. 

“Our findings show that a relatively small population of immature NK cells can have a disproportionately harmful effect on the entire therapeutic product,” said principal investigator Katy Rezvani, M.D., Ph.D., vice president and head of the Institute for Cell Therapy Discovery & Innovation, and professor of Stem Cell Transplantation and Cellular Therapy. “Importantly, this is a problem we can potentially address with a straightforward manufacturing strategy by removing these cells before therapy production.”  

The study was led by first and co-corresponding author Ye Ethan Li, M.D., Ph.D., an assistant professor at UT MD Anderson whose work helped define the biological differences between these NK cell populations and uncover the mechanism responsible for impaired CAR NK cell function. 

What are CAR NK cell therapies?  

CAR NK cells are an investigational ‘off-the-shelf’ immunotherapy in which natural killer cells are engineered to better recognize and eliminate cancer cells. At UT MD Anderson, researchers have pioneered the development of off-the-shelf CAR NK cell therapies manufactured from donated umbilical cord blood.  

Unlike patient-specific cell therapies, cord blood-derived CAR NK cells can be manufactured in advance, cryopreserved and potentially made readily available to patients when needed. 

However, donor cord blood units contain biologically diverse populations of NK cells. The researchers sought to understand whether this cellular composition could influence the quality and effectiveness of the final CAR NK cell product. 

What are the key findings of the study?  

Researchers discovered that immature NK cells can pick up proteins from cancer cells after coming into contact with them. This process is known as trogocytosis. 

As a result, the immature NK cells begin to display cancer proteins on their own surface. The engineered CAR NK cells can then mistake these immature immune cells for cancer cells and attack them. In effect, the immature NK cells create false targets that distract the therapeutic cells from the cancer. 

These interactions reduced the fitness and persistence of the stronger NK cells and weakened their ability to control the tumor. 

Can removing immature NK cells improve CAR NK cell therapy? 

When the immature NK cells were removed before manufacturing, the remaining cells were more effective, persisted longer and showed stronger antitumor activity. This strategy enhanced tumor control and survival in preclinical models of lymphoma and ovarian cancer.  

The study provides a new framework for selecting donor cord blood and manufacturing CAR NK cell therapies. Researchers now are working to incorporate these findings into next-generation CAR NK cell platforms with the goal of producing more consistent, potent and durable therapies for patients. 

*** 

This research was supported by philanthropic contributions to the Institute for Cell Therapy Discovery & Innovation at UT MD Anderson. For a full list of collaborating authors, disclosures and funding sources, see the full paper in Cancer Cell.   

– 30 –

Journal

Cancer Cell

DOI

10.1016/j.ccell.2026.06.017

CAR T-cell therapy, a revolutionary immunotherapeutic approach, has demonstrated remarkable success in hematological cancers by genetically reprogramming patients’ T cells to identify and eradicate malignant cells. However, translating this success to solid tumors, such as breast cancer, has been fraught with complexity due to the tumor microenvironment’s suppressive nature and the heterogeneity of cancerous lesions. Dr. Duda’s study, recently published in Cancer Letters, meticulously explores how CAR T-cells may be harnessed in combination with radiotherapy to overcome these formidable barriers intrinsic to solid tumors like TNBC.

The research highlights that the therapeutic efficacy of CAR T-cells is contingent upon a critically low residual cancer burden, especially in metastatic sites. This finding underscores a pivotal timing strategy where administering CAR T-cell therapy shortly after primary tumor resection or radiation could be instrumental in targeting microscopic disseminated disease not detectable through conventional imaging—thereby minimizing relapse rates. This temporal therapeutic window represents a significant advancement in tailoring immunotherapy to the biological behavior of TNBC.

In extensive in vivo experiments employing sophisticated murine models, the investigators evaluated the synergistic effects of localized radiation and CAR T-cell infusion. Radiation was found to induce immunogenic modulation of tumor cells, increasing their susceptibility to CAR T-cell mediated cytotoxicity. This combinatorial approach not only decelerated primary tumor progression but critically inhibited metastatic spread to vital organs such as the lungs and liver—a leading cause of mortality in breast cancer patients.

Further molecular analysis revealed that radiotherapy polarizes the tumor microenvironment, altering cytokine profiles and expression of immune checkpoint molecules, thereby partially reversing immune evasion mechanisms. Consequently, CAR T-cells function more effectively post-radiation, especially against metastatic lesions previously refractory to other forms of immunotherapy. These insights provide a mechanistic rationale for integrating CAR T cells with radiotherapy in solid tumor contexts, a strategy previously considered challenging.

One of the fundamental challenges in treating TNBC lies in its heterogeneity and propensity for early dissemination, often leading to micrometastases that evade detection and later precipitate relapse. The study’s demonstration that CAR T-cell therapies are most potent when administered in a minimal residual disease setting lends support to adjuvant immunotherapeutic protocols—a potential paradigm shift away from treatment of bulky, established tumors toward preemptive, precise immune interventions.

The investigators also underscore the importance of antigen specificity in the design of CAR T-cell constructs tailored for breast cancer. Unlike hematological malignancies where target antigens are relatively uniform, TNBC exhibits diverse antigenic profiles. By tailoring CAR T-cells to recognize antigens upregulated following radiation, the therapy gains specificity, minimizing off-target effects and enhancing the therapeutic index—an essential consideration for clinical translation.

While the study’s findings are derived from preclinical models, their implications for future clinical trial design are profound. The data advocates for strategically timed, multimodal therapeutic regimens combining surgery, radiotherapy, and immunotherapy to harness synergistic mechanisms for durable remission. These insights pave the way for carefully engineered human trials, which could culminate in improved survival outcomes for patients with aggressive breast cancers that have historically been resistant to treatment.

Moreover, this research addresses a critical unmet need in oncology: the effective targeting of metastatic disease. By demonstrating that targeted radiotherapy can “prime” distant metastatic sites for CAR T-cell mediated eradication, the study provides a framework for overcoming immune resistance and achieving systemic disease control.

Dr. Duda and his collaborators executed this comprehensive investigation during their tenure at Massachusetts General Hospital, involving a multidisciplinary team including immunologists, oncologists, and molecular biologists. The study’s success owes much to this collaborative environment, which integrated cutting-edge cancer biology with translational immunotherapy advancements.

The study was financially supported by the National Institutes of Health under grant R03CA256764, enabling the team to perform rigorous experimentation and data analysis. Dr. Duda’s role as a Katz Investigator at Houston Methodist Research Institute signifies his continued commitment to advancing tumor immunology and crafting innovative therapeutic strategies to combat refractory cancers.

Overall, this research delineates a feasible and scientifically robust blueprint for enhancing CAR T-cell therapy’s reach into the realm of solid tumors, particularly difficult-to-treat malignancies like triple-negative breast cancer. By elucidating optimal timing, combination strategies, and mechanistic underpinnings, it sets the stage for a new wave of immuno-oncological innovations, potentially reshaping the clinical landscape for millions of patients worldwide.

Subject of Research: Triple-Negative Breast Cancer; CAR T-cell Therapy; Radiation Therapy; Immunotherapy in Solid Tumors

Article Title: Enhancing CAR T-cell Therapy Efficacy in Triple-Negative Breast Cancer Through Combination with Radiotherapy

News Publication Date: Not provided

Web References: Link to study on ClinicalKey

References: Duda et al., Cancer Letters, NIH grant R03CA256764

Keywords: Triple-negative breast cancer, CAR T-cell therapy, Radiation therapy, Immunotherapy, Solid tumors, Tumor microenvironment, Metastasis, Cancer recurrence, Immunogenic modulation

CAR T cell therapy, a revolutionary cancer treatment that engineers a patient’s own immune cells to target malignant cells, has achieved spectacular success in hematologic malignancies but has faced formidable barriers in solid tumors such as bladder cancer. One of the key challenges lies in the insufficient and heterogeneous expression of antigens that CAR T cells can recognize and target. NECTIN4, a cell adhesion molecule commonly overexpressed in bladder tumors, represents a promising antigenic target; however, its variable expression limits therapeutic consistency. The new findings shine a light on the capacity to elevate NECTIN4 levels by fine-tuning intracellular signaling pathways, providing a strategic lever to amplify CAR T cell recognition and lethality.

The investigators homed in on the peroxisome proliferator-activated receptor gamma (PPARγ) pathway, a nuclear receptor intricately involved in lipid metabolism, inflammation, and cellular differentiation. While PPARγ has been extensively studied in metabolic diseases, its role in the modulation of tumor antigen expression had remained largely unexplored. By pharmacologically activating PPARγ, the researchers observed a robust increase in NECTIN4 surface expression on bladder cancer cells. This upregulation created a more conspicuous target for CAR T cells engineered to recognize NECTIN4, markedly boosting their cytotoxic activity against tumor cells.

Intriguingly, the study elucidates the molecular underpinnings of this modulation, revealing that PPARγ activation triggers transcriptional programs that remodel tumor cell phenotypes. The researchers employed RNA sequencing and chromatin immunoprecipitation assays to map the downstream effectors, identifying that PPARγ activation enhances NECTIN4 gene transcription via promoter binding and epigenetic changes favoring gene accessibility. These insights not only clarify the mechanism of action but also underscore the potential for fine-tuning tumor antigen landscapes through targeted pathway modulation.

In preclinical models, including patient-derived xenografts and organoids, the combinatorial treatment comprising PPARγ agonists alongside NECTIN4-specific CAR T cells achieved impressive tumor regression. This synergy translated into prolonged survival and reduced tumor burden without exacerbating toxicity, pointing toward a feasible therapeutic window. Notably, the modulation approach did not adversely alter the overall viability or phenotype of the T cells themselves, alleviating concerns regarding off-target effects or exhaustion.

The team’s meticulous exploration extended beyond efficacy to address critical hurdles in CAR T therapy such as tumor heterogeneity and immune evasion. By rendering the antigen more uniformly expressed across tumor populations, the PPARγ pathway modulation mitigated one of the canonical resistance mechanisms that hamper immunotherapy success. These findings hint at broader applicability, suggesting that strategic modulation of nuclear receptor pathways could be leveraged to enhance antigen density in other solid tumors resistant to immunotherapeutic interventions.

Furthermore, the authors discuss the translational potential of existing clinically approved PPARγ agonists, historically used in metabolic disorders such as diabetes, as adjuvant agents in immunotherapy regimens. This repurposing avenue presents an accelerated path to clinical trials, bypassing the protracted drug development timeline. The concept of harnessing metabolic regulators to sensitize tumors to immune attack represents a paradigm shift, aligning metabolic modulation with immuno-oncology for maximal therapeutic impact.

Additionally, this work highlights a critical convergence of metabolic signaling and immune recognition, a frontier area in cancer biology gaining momentum. It underscores the intricate crosstalk between tumor cell-intrinsic pathways and extrinsic immune surveillance, intricately orchestrated at the molecular level. By strategically manipulating this crosstalk, therapy can be tailored not merely to kill cancer cells but to reprogram their intrinsic identity, rendering them more vulnerable to immune-mediated clearance.

The implications extend to biomarker development as well. NECTIN4 expression levels, modulated by PPARγ activity, could serve as dynamic biomarkers to monitor therapeutic response or to stratify patients for personalized CAR T therapy regimens. This adaptive biomarker model advocates for real-time monitoring of tumor antigen status, facilitating iterative treatment adjustments that optimize clinical outcomes.

From a broader perspective, the study presents a compelling case for integrative oncology approaches that combine molecular biology, immunology, and pharmacology to overcome entrenched clinical challenges. Such interdisciplinary strategies promise to unlock new therapeutic windows previously deemed inaccessible. The convergence of CAR T cell engineering and pathway-specific tumor modulation embodies the cutting edge of precision medicine, delivering hope for patients with recalcitrant bladder cancers.

The research also addresses safety considerations by demonstrating minimal off-target PPARγ activation effects in non-malignant cells within the tumor microenvironment. This selectivity is crucial as indiscriminate modulation could potentially alter immune cell subsets or promote adverse metabolic shifts. The careful dosing and timing parameters established in the study provide a blueprint for balancing efficacy with safety in subsequent clinical translations.

An exciting frontier raised by these findings is the prospect of designing next-generation CAR T therapies coupled with built-in molecular modulators, enabling autonomous tumor antigen upregulation upon CAR engagement. Such ‘smart’ CAR T cells could dynamically adjust their targets, circumventing antigen loss variants that frequently lead to relapse. This visionary approach could herald a transformative leap in solid tumor immunotherapy.

Moreover, the study opens avenues for combining PPARγ pathway modulation with other immunomodulatory agents such as checkpoint inhibitors or cytokine therapies, potentially orchestrating a multi-pronged assault on bladder tumors. The combinatorial landscape enabled by this discovery expands the arsenal against a notoriously tough-to-treat cancer type, offering hope for durable remissions.

In conclusion, the elegant work by Chang and colleagues represents a watershed moment in bladder cancer research, illustrating the profound therapeutic synergy achievable by integrating molecular pathway modulation with immune cell engineering. By enhancing NECTIN4 expression through PPARγ activation, the study overcomes intrinsic barriers to effective CAR T cell therapy in solid tumors, offering a beacon of hope in the oncology community. As this promising avenue advances toward clinical validation, it sets a precedent for harnessing the molecular malleability of tumors to amplify immunotherapy’s curative potential.

Subject of Research: Enhancing CAR T cell therapy efficacy in bladder cancer through modulation of the PPARγ pathway to upregulate NECTIN4 expression.

Article Title: Modulating the PPARγ pathway upregulates NECTIN4 and enhances chimeric antigen receptor (CAR) T cell therapy in bladder cancer.

Article References:
Chang, K., Delavan, H.M., Yip, E. et al. Modulating the PPARγ pathway upregulates NECTIN4 and enhances chimeric antigen receptor (CAR) T cell therapy in bladder cancer. Nat Commun 16, 8215 (2025). https://doi.org/10.1038/s41467-025-62710-0

Image Credits: AI Generated

CAR T cell therapy has revolutionized hematologic oncology with remarkable success against blood cancers by redirecting immune cells to target malignant cells specifically. However, solid tumors such as glioblastoma have historically resisted such approaches due to their unique microenvironment and immune evasive mechanisms. The Penn team’s breakthrough lies in their dual-targeted CAR T cells, designed to address this challenge by simultaneously engaging two proteins frequently overexpressed in GBM: epidermal growth factor receptor (EGFR) and interleukin-13 receptor alpha 2 (IL13Rα2). This bivalent targeting increases the therapy’s precision and potency, while delivery directly into the cerebrospinal fluid enhances tumor site accessibility.

The clinical trial recruited 18 patients suffering from recurrent GBM, a notoriously resilient cancer that typically recurs within months of standard surgical and adjuvant therapies. All patients underwent maximal tumor resection before receiving an intracerebroventricular infusion of the dual-targeted CAR T cells. Remarkably, among those with measurable tumors post-surgery, nearly two-thirds (62 percent) experienced significant tumor reduction following treatment. While the reduction was often transient, the therapy altered the disease’s natural trajectory, translating into meaningful periods of progression-free survival and quality of life improvements.

This dual-pronged CAR T cell injection exhibited durability beyond immediate effects, with immune surveillance markers detected in cerebrospinal fluid samples months after infusion. In some instances, CAR T cells remained active for over a year, a testament to the persistent immune engagement against residual tumor cells. One patient, notably, displayed extensive immune cell infiltration—comprised of T cells and macrophages—within tumor tissue excised after relapse, confirming the immune system’s ongoing response driven by the therapy.

These early clinical observations not only reinforce the therapeutic potential of CAR T cells in solid tumor brain neoplasms but also challenge the longstanding assumption that the brain’s immune-privileged status precludes effective immunotherapy. Delivery via cerebrospinal fluid appears to circumvent traditional obstacles like the blood-brain barrier, allowing engineered immune cells direct access to tumor sites. This modality may herald a paradigm shift in treating central nervous system malignancies.

Safety considerations, paramount in any novel therapy, were rigorously monitored, revealing manageable neurotoxicity in over half of the patients at grade 3 severity. Importantly, these adverse events aligned with known side effects of existing FDA-approved CAR T therapies and were effectively managed without introducing unexpected complications. This points to the feasibility of administering such therapies within a controlled clinical setting, balancing efficacy with patient safety.

The study’s findings carry significant implications for the future of GBM treatment. The median survival for patients following recurrence traditionally falls between 6 to 10 months, with few effective options available beyond palliative care. Yet, in this trial, some patients surpassed the one-year survival benchmark, including one individual who maintained stable disease for more than 16 months despite initial advanced tumor spread and aggressive progression. These outcomes advocate for the expansion of clinical investigations, particularly focusing on the application of dual-target CAR T therapy earlier in the disease course.

Researchers aim to optimize therapeutic efficacy by exploring repeat dosing strategies in subsequent trial phases. The current study administered a single infusion, but ongoing efforts seek to determine whether multiple administrations can sustain or enhance tumor control over longer periods. This approach could be transformative, converting temporary remission into durable responses or even long-term remission.

Beyond glioblastoma, this dual-target CAR T platform serves as a proof of concept for multi-antigen targeting in challenging solid tumors, potentially extending to other refractory cancers exhibiting heterogeneous antigen expression. By broadening the immune system’s attack scope, this strategy counters tumor escape pathways that rely on downregulating or mutating single antigen targets.

Academically, this research signifies a milestone in onco-immunology, integrating cutting-edge gene editing, neuro-oncology, and immunotherapy. The work stems from the laboratory of Dr. Donald M. O’Rourke, whose pioneering efforts in neuroimmunotherapy have defined new frontiers in treating brain cancers. Collaboratively, the study aligns with Penn’s commitment to translating laboratory innovations into clinical realities, driving hope for patients confronting otherwise dismal prognoses.

The trial’s momentum, bolstered by support from Kite, a Gilead Company, alongside the Abramson Cancer Center and philanthropic initiatives, underscores the critical role of interdisciplinary and multi-sector partnerships in achieving breakthroughs. As the therapy advances toward trials in newly diagnosed GBM patients, the oncology community eagerly anticipates whether earlier intervention will further enhance outcomes and redefine standards of care for this devastating disease.

In summary, the intracerebroventricular bivalent CAR T cell therapy represents a pioneering stride in confronting recurrent glioblastoma, demonstrating both tumor regression and manageable safety profiles. While further research and larger clinical trials are essential to confirm and broaden these findings, the current data illuminate a promising path towards harnessing the immune system’s power against one of the most formidable cancers afflicting the brain.

Subject of Research: Dual-target CAR T cell therapy for recurrent glioblastoma

Article Title: Intracerebroventricular bivalent CAR T cells targeting EGFR and IL-13Rα2 in recurrent glioblastoma: a phase 1 trial

News Publication Date: June 1, 2025

Web References:
https://www.pennmedicine.org/treatments/car-t-cell-therapy
https://www.asco.org/annual-meeting
https://www.nature.com/articles/s41591-025-03745-0
https://clinicaltrials.gov/study/NCT06973096

References:
Bagley, S. et al. Intracerebroventricular bivalent CAR T cells targeting EGFR and IL-13Rα2 in recurrent glioblastoma: a phase 1 trial. Nature Medicine. 2025. DOI: 10.1038/s41591-025-03745-0.

Keywords: Glioblastoma, Brain cancer, CAR T cell therapy, Cancer immunotherapy, Dual-target CAR T, EGFR, IL13Rα2, Immunotherapy, Neuro-oncology, Tumor microenvironment