Researchers at the University of Pennsylvania's Perelman School of Medicine have, for the first time, demonstrated the use of lab-grown organoids derived from glioblastoma (GBM) tumors to accurately model a patient’s response to chimeric antigen receptor (CAR)-T cell therapy in real time. This innovative approach, detailed in Cell Stem Cell, holds promise for personalized medicine and improved treatment strategies for this aggressive brain cancer.
The study involved creating organoids from tumors of patients with recurrent glioblastoma participating in a Phase I clinical trial for a dual-target CAR-T cell therapy. These glioblastoma organoids (GBOs) were treated in parallel with the patients, and the results indicated a strong correlation between the organoid's response and the patient's actual tumor response.
Real-Time Modeling of Treatment Response
According to Hongjun Song, PhD, the Perelman Professor of Neuroscience, "These organoids reflect what is happening in an individual’s brain with great accuracy, and we hope that they can be used in the future to 'get to know' each patient’s distinctly complicated tumor and quickly determine which therapies would be most effective for them for personalized medicine." The ability to measure a patient's response to GBM treatment is challenging due to the difficulty in obtaining regular brain biopsies and distinguishing tumor growth from treatment-related inflammation on MRI imaging.
The study confirmed that if the tumor-derived organoid shrank after treatment, so did the patient’s actual tumor. This real-time correlation offers a significant advantage in assessing treatment efficacy and tailoring therapies accordingly.
Addressing Challenges in GBM Treatment
GBM is the most common and aggressive type of cancerous brain tumor in adults, with a typical survival expectancy of just 12–18 months following diagnosis. Despite extensive research, there is no known cure, and current treatments like surgery, radiation, and chemotherapy have limited impact on prolonging life expectancy.
Guo-li Ming, MD, PhD, the Perelman Professor of Neuroscience and Associate Director of Institute for Regenerative Medicine, explained, "One of the reasons why GBM is so difficult to treat is because the tumors are incredibly complicated, made up of several different types of cancer cells, immune cells, blood vessels, and other tissue." This complexity necessitates more sophisticated models to understand and combat the disease.
Potential for Personalized Medicine
CAR-T cell therapy, which reprograms a patient’s T cells to target and destroy specific cancer cells, has shown promise in blood cancers but faces challenges in solid tumors like GBM. Recent research suggests that targeting two brain tumor-associated proteins may improve outcomes.
The researchers found that the treatment response in the organoids correlated with the response of the tumors in the patient. When a patient’s organoid demonstrated cancer cell destruction by T cells, the patient also exhibited a reduced tumor size via MRI imaging and an increased presence of CAR-positive T cells in their cerebrospinal fluid, indicating that the therapy met its targets.
Predicting Neurotoxicity
A common concern with CAR T cell therapy for GBM is neurotoxicity. The study found similar levels of immune cytokines, indicative of toxicity, in both the organoids and the patients’ cerebrospinal fluid (CSF). These levels decreased a week after treatment, suggesting that organoids can accurately model a patient’s risk of neurotoxicity and help determine the appropriate CAR T cell dose.
Future Applications and Clinical Impact
Donald M. O’Rourke, MD, the John Templeton, Jr., MD, professor in neurosurgery and director of the Glioblastoma Translational Center of Excellence at the Abramson Cancer Center, stated, "This research shows that our GBM organoids are a powerful and accurate tool for understanding what exactly happens when we treat a brain tumor with CAR T cell therapy... Our hope is that not only to bring these to clinic to personalize patient treatment, but also to use the organoids to deepen our understanding of how to outsmart and destroy this complex and deadly cancer."
The team suggests that their results could pave the way for future applications of GBOs in testing patient responses to treatments, selecting personalized therapies, and stratifying patients for clinical trials. This approach could be critical in improving outcomes for GBM patients, given the short survival period after diagnosis.
