WASHINGTON (AP) 鈥� A new strategy to fight an extremely aggressive type of brain tumor showed promise in a pair of experiments with a handful of patients.
Scientists took patients鈥� own immune cells and able to recognize and attack glioblastoma. In the first-step tests, those cells shrank tumors at least temporarily, researchers reported Wednesday.
So-called CAR-T therapy already is used like leukemia but researchers have struggled to . Now separate teams at Massachusetts General Hospital and the University of Pennsylvania are developing next-generation CAR-T versions designed to get past some of glioblastoma鈥檚 defenses.
鈥淚t鈥檚 very early days,鈥� cautioned Penn鈥檚 Dr. Stephen Bagley, who led one of the studies. But 鈥渨e鈥檙e optimistic that we鈥檝e got something to build on here, a real foundation.鈥�
Glioblastoma, the brain cancer that killed President Joe Biden鈥檚 son Beau Biden and longtime Arizona Sen. John McCain, is fast-growing and hard to treat. Patients usually live 12 to 18 months after diagnosis. Despite decades of research, there are few options when it returns after surgery and radiation.
The immune system's T cells fight disease but cancer has ways to hide. With CAR-T therapy, doctors genetically modify a patient鈥檚 own T cells so they can better find specific cancer cells. Still, solid tumors like glioblastoma offer an additional hurdle 鈥� they contain mixtures of cancer cells with different mutations. Targeting just one type allows the rest to keep growing.
Mass General and Penn each developed two-pronged approaches and tried them in patients whose tumors returned after standard treatment.
At Mass General, Dr. Marcela Maus鈥� lab combined CAR-T with what are called T-cell engaging antibody molecules 鈥� molecules that can attract nearby, regular T cells to join in the cancer attack. The result, dubbed CAR-TEAM, targets versions of a protein called EGFR that鈥檚 found in most glioblastomas but not normal brain tissue.
Penn鈥檚 approach was to create 鈥渄ual-target鈥� CAR-T therapy that hunts for both that EGFR protein plus a second protein found in many glioblastomas.
Both teams infused the treatment through a catheter into the fluid that bathes the brain.
Mass General tested three patients with its CAR-TEAM and brain scans a day or two later showed their tumors rapidly began shrinking, the researchers reported in the New England Journal of Medicine.
鈥淣one of us could really believe it,鈥� Maus said. 鈥淭hat doesn鈥檛 happen.鈥�
Two of the patients' tumors began to regrow soon and a repeat dose given to one of them didn鈥檛 work. But one patient鈥檚 response to the experimental treatment lasted more than six months.
Similarly, Penn researchers reported in Nature Medicine that the first six patients given its therapy experienced varying degrees of tumor shrinkage. While some rapidly relapsed, Bagley said one treated in August so far hasn't seen regrowth.
For both teams, the challenge is to make it longer-lasting.
鈥淣one of this is going to matter if it doesn't last,鈥� Bagley said.
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The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute鈥檚 Science and Educational Media Group. The AP is solely responsible for all content.
Lauran Neergaard, The Associated Press
