Newswise — PHILADELPHIA— Immune cells engineered to seek out and attack a type of deadly brain cancer known as glioblastoma (GBM) were found to have an acceptable safety profile and successfully migrate to and infiltrate tumors, researchers from Penn Medicine and Harvard University reported at the AACR Annual Meeting 2016 (Abstract LB-083).
The phase I study tested an investigational chimeric antigen receptor (CAR) therapy made from patients’ own T cells engineered in a specialized laboratory to target a tumor-specific protein known as EGFRvIII, which is found in about 30 percent of GBM patients’ tumors. In contrast to other CAR therapies that also target some healthy cells, EGFRvIII is found only on tumor tissue, which the study’s leaders believed would minimize side effects of the new therapy.
Results from nine patients treated so far on the trial, led by Donald M. O’Rourke, MD, an associate professor of Neurosurgery at the Perelman School of Medicine at the University of Pennsylvania, were presented by Marcela Maus, MD, PhD, a former Penn faculty member who is now the Director of Cellular Immunotherapy at the Massachusetts General Hospital Cancer Center and an assistant professor of Medicine at Harvard Medical School.
The CAR therapy was found to have an acceptable safety profile in all patients, with no clinical or laboratory signs of systemic cytokine release syndrome, a potentially serious toxicity that has been observed in other CAR trials. One patient experienced a seizure (non-convulsive status epilepticus); however, it was successfully treated by antiepileptic medications. All patients had significant expansion of CART-EGFRvIII cells in their blood between 7 and 10 days after infusion. Also, a pathologic evaluation of tumors surgically removed from five patients between 6 and 120 days after infusion revealed focal areas which showed infiltration of both CAR positive and CAR negative T cells with signs of activation, the researchers reported.
“One of the main questions in the field of T cell therapies is: can we make this work in solid tumors?” Maus said. “The barriers to CAR T cells in solid tumors are identifying targets with acceptable safety profiles, proving that T cells can get out of the blood, and that they can successfully target the tumor cells expressing the antigen without being turned off by the tumor environment.
“Here, we demonstrated that targeting EGFRvIII has an acceptable safety profile, that CAR T cells do actually find their way and get into the tumor--even crossing the blood-brain barrier--and are able to eliminate the target.”
The new study was born of an interdisciplinary collaboration: neurosurgeons, neuro-oncologists, neuropathologists, immunologists, and transfusion medicine experts have all played key roles in developing the investigational therapy. Penn is the first institution to open a trial utilizing this type of CAR T cell therapy for glioblastoma, and a second study site is now open at the University of California, San Francisco.
The phase I trial will include a total of 12 adult patients whose tumors express EGFRvIII.
After some of each patient’s T cells are removed via an apheresis process similar to dialysis, the cells are engineered using a viral vector that programs them to hunt for cancer cells that express EGFRvIII. Then, the new cells are infused back into the patient’s bodies, where a signaling domain built into the CAR promotes rapid growth of these cells, building an army of tumor-killing cells that have been shown in studies of blood cancer patients to persist in the body. The investigators believe the cells may then serve as a vaccine-like protection against tumor recurrence.
More than 22,000 Americans are diagnosed with GBM each year. Patients whose tumors express the EGFRvIII mutation tend to have more aggressive cancers: Their tumors are less likely to respond to standard therapies. “We now need to see in the next set of patients if we can augment the effects of the CAR infiltration into the brain and determine optimal timing and combination of this therapy with other established therapies,” O’Rourke said. “In this manner, we believe this highly personalized T cell therapy will begin to show clinical efficacy in a reproducible manner with all patients containing EGFRvIII-positive GBMs.”
Penn co-authors include MacLean P. Nasrallah, Jennifer Morrissette, Jan J. Melenhorst, Simon F. Lacey, Maria Martinez-Lage, Arati Desai, Steven Brem, Eileen Maloney, Suyash Mohan, Sumei Wang, Gaurav Verma, Jean-Marc Navenot, Zhaohui Zheng, Bruce L. Levine, and Carl H. June.
Other authors include Keith Mansfield, Randi Isaacs, Jennifer Brogdon and Angela Shen, from Novartis, and Hideho Okada from University of California, San Francisco. The clinical trial is sponsored by Novartis. In 2012, the University of Pennsylvania and Novartis announced an exclusive global research and licensing agreement to further study and commercialize novel cellular immunotherapies using CAR technologies.
For more information about the glioblastoma trial, visit clinicaltrials.gov.
Editor’s Note: Some of the scientists at the University of Pennsylvania and Novartis are inventors of these technologies, and the University as well as the inventors may benefit financially from this work in the future.
##Penn Medicine is one of the world's leading academic medical centers, dedicated to the related missions of medical education, biomedical research, and excellence in patient care. Penn Medicine consists of the Raymond and Ruth Perelman School of Medicine at the University of Pennsylvania (founded in 1765 as the nation's first medical school) and the University of Pennsylvania Health System, which together form a $5.3 billion enterprise.The Perelman School of Medicine has been ranked among the top five medical schools in the United States for the past 18 years, according to U.S. News & World Report's survey of research-oriented medical schools. The School is consistently among the nation's top recipients of funding from the National Institutes of Health, with $373 million awarded in the 2015 fiscal year.The University of Pennsylvania Health System's patient care facilities include: The Hospital of the University of Pennsylvania and Penn Presbyterian Medical Center -- which are recognized as one of the nation's top "Honor Roll" hospitals by U.S. News & World Report -- Chester County Hospital; Lancaster General Health; Penn Wissahickon Hospice; and Pennsylvania Hospital -- the nation's first hospital, founded in 1751. Additional affiliated inpatient care facilities and services throughout the Philadelphia region include Chestnut Hill Hospital and Good Shepherd Penn Partners, a partnership between Good Shepherd Rehabilitation Network and Penn Medicine.Penn Medicine is committed to improving lives and health through a variety of community-based programs and activities. In fiscal year 2015, Penn Medicine provided $253.3 million to benefit our community.
RSS