IL13-PE38QQR is an oncology drug product consisting of IL13 (interleukin-13) and PE38QQR (a bacteria toxin). IL13-PE38QQR is a protein that exhibits cell killing activity against a variety of IL13 receptor-positive tumor cell lines indicating that it may show a therapeutic benefit. In reciprocal competition experiments, the interaction between IL13-PE38QQR and the IL13 receptors was shown to be highly specific for human glioma cells.