pazopanib and Macular-Degeneration

To evaluate pazopanib eye drops in patients with subfoveal choroidal neovascularisation secondary to age-related macular degeneration.. 70 patients with minimally classic or occult subfoveal choroidal neovascularisation were randomly assigned to 5 mg/mL TID, 2 mg/mL TID, and 5 mg/mL QD pazopanib eye drops for 28 days in a multicentre, double-masked trial with an optional safety extension for up to 5 additional months. The primary outcomes were central retinal thickness (CRT) and best-corrected visual acuity (BCVA) at Day 29.. No significant decrease from baseline in CRT was observed overall; however, an exploratory analysis showed improvement in CRT (mean decrease of 89 μm) in patients with the CFH TT genotype who received 5 mg/mL TID (p=0.01, n=5). Mean increases in BCVA were observed in the 5 mg/mL TID overall (4.32 letters (p=0.002, n=26)) and in those that with CFH Y402H TT (6.96 letters (p=0.02, n=5)) and CT (4.09 letters (p=0.05, n=9)) genotypes. No safety signals that precluded continued investigation were detected.. 5 mg/mL pazopanib eye drops resulted in mean improvement in BCVA at Day 29 and improvements in vision. However, improvement in macular oedema for age-related macular degeneration was found only in the subset of subjects with the CFH Y402H TT genotype, warranting further investigation.

Topics: Angiogenesis Inhibitors; Choroidal Neovascularization; Dose-Response Relationship, Drug; Double-Blind Method; Female; Follow-Up Studies; Humans; Indazoles; Macular Degeneration; Male; Middle Aged; Ophthalmic Solutions; Prospective Studies; Pyrimidines; Sulfonamides; Treatment Outcome; Visual Acuity

Age-related macular degeneration (AMD) is the leading cause of severe vision impairment in patients over the age of 60 years. Choroidal neovascularization (CNV) is the hallmark of neovascular AMD and vascular endothelial growth factor (VEGF) plays a causal role in the formation of CNV. Although regorafenib and pazopanib, small molecule VEGF receptor (VEGFR) inhibitors, were developed as eye-drops, their efficacies were insufficient in clinical. In this study, we evaluated ocular pharmacokinetics and pharmacological activities of regorafenib and pazopanib after ocular instillation in multiple animal species. In rats, both regorafenib and pazopanib showed high enough concentrations in the posterior eye tissues to inhibit VEGFR. In laser-induced rat CNV model, regorafenib showed clear reduction in CNV area. On the other hand, the concentrations of regorafenib and pazopanib in the posterior eye tissues were much lower after ocular instillation in rabbits and monkeys compared to those in rats. Pazopanib did not show any improvement in monkey model. Regorafenib was nano-crystalized to improve its drug delivery to the posterior eye tissues. The nano-crystalized formulation of regorafenib showed higher concentrations in the posterior segments in rabbits compared to its microcrystal suspension. From these studies, large interspecies differences were found in ocular delivery to the posterior segments after ocular instillation. Such large interspecies difference could be the reason for the insufficient efficacies of regorafenib and pazopanib in clinical studies. Nano-crystallization was suggested to be one of the effective ways to overcome this issue.

Topics: Angiogenesis Inhibitors; Animals; Choroidal Neovascularization; Crystallization; Disease Models, Animal; Drug Evaluation, Preclinical; Eye; Female; Humans; Indazoles; Macaca fascicularis; Macular Degeneration; Male; Nanoparticles; Ophthalmic Solutions; Particle Size; Phenylurea Compounds; Pyridines; Pyrimidines; Rabbits; Rats; Receptors, Vascular Endothelial Growth Factor; Species Specificity; Sulfonamides; Vascular Endothelial Growth Factor A

Neovascularization in the eye is a major cause of irreversible vision loss. The present study was undertaken to determine mechanisms through which pazopanib, a drug that targets multiple receptor tyrosine kinases such as VEGF receptors, inhibits angiogenesis and experimental choroidal neovascularization (CNV). Pazopanib inhibited VEGF expression by retinal pigment epithelium (RPE) cells and choroidal endothelial cells (CEC), decreased VEGF-induced cellular migration in a dose-dependent manner and suppressed extracellular signal-regulated kinase (ERK)-1/-2 phosphorylation. To assess the impact of pazopanib in vivo, CNV was induced in rats by rupturing the Bruch's membrane by laser coagulation. These experiments demonstrated that twice-daily topical eye drop treatment significantly (P<0.001) decreased leakage from photocoagulated lesions by 89.5%. Furthermore, the thickness of the developed CNV lesions was significantly inhibited by 71.7% (P<0.001) in pazopanib-treated eyes, and immunoreactivity of VEGF was lower than in control eyes. Our data suggest that pazopanib is a promising inhibitor of angiogenesis leading to an effective inhibition of CNV development in vivo. This activity can be largely ascribed to the down-regulation of VEGF release in the retina as well as to impaired VEGF-induced signaling and chemotaxis. Using a convenient topical dosing regimen, pazopanib may prove useful for treating a variety of ocular neovascular diseases such as neovascular age-related macular degeneration.

Topics: Administration, Topical; Angiogenesis Inhibitors; Animals; Cell Movement; Choroid; Down-Regulation; Endothelial Cells; Humans; Indazoles; Intracellular Space; Macular Degeneration; Male; Neovascularization, Pathologic; Protein Kinase Inhibitors; Pyrimidines; Rats; Receptor Protein-Tyrosine Kinases; Signal Transduction; Sulfonamides; Vascular Endothelial Growth Factor A