In two trials, a novel approach to treating a very aggressive form of brain tumor showed promise with a small number of patients.
Using the immune cells from the patients, scientists created “living drugs” that could identify and combat glioblastoma. Researchers revealed on Wednesday that such cells, at least momentarily, shrunk tumors in the first-step testing.
Although leukemia and other blood-related cancers are already treated using so-called CAR-T therapy, researchers have had difficulty adapting this treatment to treat solid tumors. Presently, distinct groups at the University of Pennsylvania and Massachusetts General Hospital are creating next-generation CAR-T variants that are intended to overcome some of the defenses put up by glioblastoma.
The head of one of the investigations at Penn, Dr. Stephen Bagley, issued a warning: “It’s very early days.” However, “we’re confident that we have a solid foundation here on which to build.”
The brain tumor known as glioblastoma, which claimed the lives of longtime Arizona senator John McCain as well as President Joe Biden’s son Beau, is incurable and spreading quickly. After diagnosis, patients typically live for 12 to 18 months. When it reappears after surgery and radiation, there aren’t many choices, despite decades of research.
T cells in the immune system combat illness, but cancer has ways of hiding. Doctors genetically alter a patient’s own T cells with CAR-T treatment to help them more effectively locate particular cancer cells. However, solid tumors such as glioblastoma present an extra challenge because they comprise combinations of cancer cells with
Both Mass General and Penn created two-pronged strategies that they applied to individuals whose tumors reappeared following conventional therapy.
The lab of Dr. Marcela Maus at Mass General paired CAR-T with molecules known as T-cell engagement antibody molecules, which have the ability to draw in neighboring normal T cells to assist in the cancer attack. The outcome, known as CAR-TEAM, targets EGFR protein variants, which are present in most glioblastomas but absent from healthy brain tissue.
Penn’s strategy involved developing “dual-target” CAR-T therapy, which looks for the EGFR protein in addition to another protein that is present in a large number of glioblastomas.
Using a catheter, both teams injected the medication into the fluid surrounding the brain.
It was quite unbelievable to all of us,” Maus remarked. “That isn’t the case.“
The tumors in two of the patients quickly started to develop again, and one of them did not respond well to a repeat dosage. However, the experimental treatment’s effects on one patient persisted for more than six months.
Similarly, the first six patients receiving the therapy saw varied degrees of tumor decrease, according to a Penn study published in Nature Medicine. While others relapsed quickly, Bagley added that one patient treated in August has not seen any regrowth to date.
Making it last longer is the challenge for both teams.
“If it doesn’t work out, none of this will matter,” Bagley remarked.
