Generally, childhood cancers can be fairly treatable. However, some brain cancers, such as malignant astrocytomas of the brainstem and cerebral hemispheres and multiply recurrent low-grade gliomas don't respond well to treatment and the outcomes are not good for the patient. Adult gliomas can be treated with immunotherapies, and a group from the University of Pittsburgh Cancer Institute decided to see how the approach would work in children.
The researchers selected a group of children with newly diagnosed brainstem gliomas (BSG), cerebral high-grade gliomas (HGG), or recurrent gliomas. They gave them vaccines targeted to antigens lined with the cancers (glioma-associated antigens or GAA). The vaccine was well tolerated but three children's tumors enlarged, causing some neurological problems (known as pseudoprogression). However, these resolved and the tumors either regressed to some extent or became stable. Of the 22 children treated, 18 showed some response to the vaccine, including one child who became disease-free. The results were presented at the AACR Annual Meeting 2012.
"These kids, who, for the most part, have intact and very robust immune systems, seem to mount an immune response against the vaccine very effectively at rates that may be even higher than have been noted in studies in adults," said Dr. Ian F. Pollack, the Walter Dandy professor of neurological surgery at the University of Pittsburgh School of Medicine. "This was the first study of its type that examined peptide vaccine therapy for children with brain tumors like this," Pollack said. "The fact that we've seen tumor shrinkage in children with very high-risk tumors has been extremely encouraging and somewhat surprising."
"The safe and potentially effective nature of this vaccine would give thousands of patients new hope," Dr. John Yu, director of surgical neuro-oncology and vice chair of the department of neurosurgery at the Cedars-Sinai Medical Center told HealthDay. "Although one cannot glean whether this will improve their overall survival while maintaining a good quality of life, it provides some hope that harnessing the power of the immune system to fight off the brainstem glioma may kill tumor cells and provide a novel means of fighting off their disease."