Emixustat, is an inhibitor of the visual cycle isomerase with an IC50 value of 4.4 nM in vitro. a novel visual cycle modulator.

Visual cycle isomerase:4.4 nM

Emixustat strongly inhibits 11-cis-retinol production with an IC50 value of 232±3 nM.Emixustat potently inhibits isomerase activity in vitro (IC50=4.4 nM). Treatment of emixustat shows a concentration dependent reduction of 11-cis-ROL production .

Pre-treatment with a single dose of emixustat (0.3 mg/kg) provides a 50% protective effect against light-induced photoreceptor cell loss, while higher doses (1-3 mg/kg) are nearly 100% effective. In Abca4-/- mice, chronic (3-month) emixustat treatment markedly reduces lipofuscin autofluorescence and lowers A2E levels by 60% (ED50=0.47 mg/kg). In the retinopathy of prematurity rodent model, emixustat administered during ischemia and reperfusion injury results in a 30% reduction in retinal neovascularization (ED50=0.46 mg/kg). Emixustat reduces the production of visual chromophore (11-cis retinal) in wild-type mice after a single oral dose (ED50=0.18 mg/kg). In albino mice, emixustat effectively prevents photoreceptor cell death caused by intense light exposure.