In trials in mice, a therapy developed at Stanford safely and effectively treated five types of pediatric brain tumors, according to new data published today in Science Translational Medicine.
The research, which was led by Stanford pediatric neurosurgeon Samuel Cheshier, MD, PhD and cancer scientist Irving Weissman, MD, used an antibody-based immune therapy to target five aggressive pediatric brain tumors: group 3 medulloblastoma, atypical teratoid rhabdoid tumor, primitive neuroectodermal tumor, pediatric glioblastoma and diffuse intrinsic pontine glioma.
The antibodies, which react with a "don't eat me" molecule called CD47, were developed in Weissman's lab and may also help treat many other kinds of cancer. They indirectly trigger targeted destruction of cancer cells by immune cells called macrophages.
In the new trials, when the antibodies were given to mice that had human tumor tissue implanted in their brains, macrophages engulfed and destroyed the brain tumor cells. And this happened without collateral damage to healthy brain cells nearby, as our press release about the paper explains:
'The most exciting aspect of our findings is that no matter what kind of brain tumor we tested it against, this treatment worked really well in the animal models,' said Cheshier, who is also a pediatric neurosurgeon at Lucile Packard Children’s Hospital Stanford. In mice that had been implanted with both normal human brain cells and human brain cancer cells, 'there was no toxicity to normal human cells but very, very active tumor-killing in vivo,' he said.
The low toxicity is a big contrast to existing therapies for pediatric brain tumors, which can be very harmful to children's developing brains.
The antibodies don't appear able to completely rid the body of large tumors on their own, the researchers caution. However, they hope that combining this form of immunotherapy with low doses of other cancer treatments may provide a treatment that is both more effective and less damaging than existing options.
Because the anti-CD47 antibodies are already being tested in a phase-1 clinical trial of adults with other forms of cancer, the researchers anticipate that the therapy will be tried in children with brain cancer fairly soon, probably within the next year or two.
Previously: A look at scientists' efforts to conquer a deadly brain tumor, Existing drug shows early promise against deadly childhood brain tumor and Single antibody shrinks or eliminates human tumors in mice at Stanford
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