ZK 219477 has the ability to cross the blood-brain barrier, a fundamental characteristic for a potential GBM chemotherapy. In a preclinical PK study, similar concentrations of ZK 219477 were detected in plasma (1.2 μg/ml) and brain (0.9 μg/g) after 10 min after i.v. application in scid mice. The AUC brain/AUC plasma was about 0.8, indicating a free access to the brain (Hoffmann J et al. 2004, European Journal Cancer Supplement 2, N 8, p. 159, Abstract 521, ref.17). ZK 219477 produced strong antiproliferative activity in the human glioma cell line U373 inoculated subcutaneous in nude mice (2 mg/kg and 9 mg/kg) as well as paclitaxel (8 mg/kg), but on the contrary of paclitaxel, only ZK 219477 demonstrated antitumour activity against U373 implanted in nude mice (9 mg/kg): 8 complete response out 9 treated mice.