[CAS NO. 1251156-08-7]  XL388

When dosed orally once daily in mice, XL388 shows robust anti-tumor activity in multiple xenograft models including > 100% tumor growth inhibition in the MCF-7 xenograft model. XL388 displays good pharmacokinetics and oral exposure in multiple species with moderate bioavailability. The mean plasma protein binding of XL388 in human, monkey, dog, rat, and mouse plasma is evaluated at 5 μM and is determined to be 86%, 90%, 89%, 85%, and 84%, respectively. Oral administration of XL388 to athymic nude mice implanted with human tumor xenografts afforded significant and dose-dependent antitumor activity. Strong inhibition of both mTORC1 and mTORC2 is achieved 4−8 h following administration orally at 100 mg/kg. Modest inhibition (39−45%) of phosphorylation of the PI3K target AKT (T308) is also observed 4−8 h post dose.