AACR: Peptide Vaccine Tested in Children With Gliomas
(HealthDay News) – For children with gliomas, vaccination with peptides for glioma-associated antigen (GAA) epitopes is generally well tolerated and has immunological and clinical activity, according to a pilot study presented at the annual meeting of the American Association for Cancer Research, held from March 31–April 4 in Chicago.
Ian F. Pollack, MD, from the Children's Hospital of Pittsburgh, and colleagues assessed the safety and treatment response to subcutaneous peptide vaccination for 13 children with newly diagnosed brainstem gliomas (BSGs), five with cerebral high-grade gliomas, and six with recurrent gliomas. The vaccine comprised peptides for GAA epitopes, given every three weeks for eight courses, together with intramuscular injections of a synthetic complex of carboxymethylcellulose, polyinosinic-polycytidylic acid, and poly-L-lysine double-stranded RNA.
The researchers did not encounter dose-limiting non-central nervous system toxicity. One child with a BSG experienced pseudoprogression (ie, transient tumor enlargement with acute neurologic deterioration) which regressed, culminating in sustained partial response. Two children with BSGs had symptomatic pseudoprogression, which stabilized with decreasing steroid doses. Twenty-two children were evaluable for response: four had rapidly progressive disease, 14 had stable disease for more than three months, two had partial responses, one had minor response, and one was disease-free after surgery. T cell responses were assessed in seven children; five, three, and three showed responses to interleukin-13-receptor-α2, ephrin type-A receptor 2 precursor, and survivin, respectively.
"This was the first study of its type that examined peptide vaccine therapy for children with brain tumors like this," Pollack said in a statement. "The fact that we've seen tumor shrinkage in children with very high-risk tumors has been extremely encouraging and somewhat surprising."