GNE-317

GNE-317 is a PI3K/mTOR inhibitor, is able to cross the blood-brain barrier (BBB). IC50 & Target: PI3K/mTOR^[1] In Vitro: GNE-317 is an oxetane derivative of GDC-0980 synthesized with the goal of reducing substrate affinity for efflux transporters. In vitro, GDC-0980 and GNE-317 demonstrate similar profiles in MTS cytotoxicity experiments using the GL261 cell line^[1]. In Vivo: Seven days after i.c. inoculation with GL261-GFP-Luc cells, mice are treated once daily with the maximum tolerated dose of GDC-0980 (7.5 mg/kg), GNE-317 (30 mg/kg), or vehicle. For GL261, tumor growth is tracked through bioluminescence imaging on a weekly basis. There are no significant changes in GL261 tumor growth among the 3 groups. In assessing survival benefits in GL261, neither GDC-0980 nor GNE-317 provides survival benefit over the vehicle-treated animals. The fact that these drugs are not effective in vivo is suggested by the in vitro cytotoxicity data showing that the drugs have limited efficacy in inducing cell death in the GL261 cell line. Neither drug is effective in the GL261 tumor in spite of greater delivery and enhanced therapeutic targeting efficacy of GNE-317^[1].