Cositecan (BNP1350) is semi-synthetic silicon-containing camptothecin and an inhibitor of topoisomerase I. It was engineered by BioNumerik Pharmaceuticals for superior oral bioavailability, lactone stability, and insensitivity to Pgp/MRP/LRP drug resistance. The compound shows a broad spectrum of activity in experimental human tumors. Cositecan was investigated in clinical trials in patients with malignant melanoma, relapsed or refractory non-small cell lung cancer, ovarian and peritoneal cancer, malignant glioma. The compound had little activity in recurrent glioma and ovarian cancer.