Characterization of Antineovascularization Activity and Ocular Pharmacokinetics of Phosphoinositide 3-Kinase/Mammalian Target of Rapamycin Inhibitor GNE-947.

The objectives of the present study were to characterize GNE-947 for its phosphoinositide 3-kinase (PI3K) and mammalian target of rapamycin (mTOR) inhibitory activities, in vitro anti-cell migration activity in human umbilical vein endothelial cells (HUVECs), in vivo antineovascularization activity in laser-induced rat choroidal neovascular (CNV) eyes, pharmacokinetics in rabbit plasma and eyes, and ocular distribution using matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS) and autoradioluminography. Its PI3K and mTOR were 0.0005 and 0.045 µM, respectively, and its HUVEC IC was 0.093 µM. GNE-947 prevented neovascularization in the rat CNV model at 50 or 100 µg per eye with repeat dosing. After a single intravenous injection at 2.5 and 500 μg/kg in rabbits, its plasma terminal half-lives ( ) were 9.11 and 9.59 hours, respectively. After a single intravitreal injection of a solution at 2.5 μg per eye in rabbits, its apparent values were 14.4, 16.3, and 23.2 hours in the plasma, vitreous humor, and aqueous humor, respectively. After a single intravitreal injection of a suspension at 33.5, 100, 200 μg per eye in rabbits, the were 29, 74, and 219 days in the plasma and 46, 143, and 191 days in the eyes, respectively. MALDI-IMS and autoradioluminography images show that GNE-947 did not homogenously distribute in the vitreous humor and aggregated at the injection sites after injection of the suspension, which was responsible for the long of the suspension because of the slow dissolution process. This hypothesis was supported by pharmacokinetic modeling analyses. In conclusion, the PI3K/mTOR inhibitor GNE-947 prevented neovascularization in a rat CNV model, with up to approximately 6 months after a single intravitreal injection of the suspension in rabbit eyes. SIGNIFICANCE STATEMENT: GNE-947 is a potent phosphoinositide 3-kinase/mammalian target of rapamycin inhibitor and exhibits anti-choroidal neovascular activity in rat eyes. The duration of GNE-947 in the rabbit eyes after intravitreal injection in a solution is short, with a half-life ( ) of less than a day. However, the duration after intravitreal dose of a suspension is long, with up to 6 months due to low solubility and slow dissolution. These results indicate that intravitreal injection of a suspension for low-solubility drugs can be used to achieve long-term drug exposure.