In vitro and in vivo efficacy of SYL040012, a novel siRNA compound for treatment of glaucoma.

Glaucoma is a progressive ocular syndrome characterized by degeneration of the optic nerve and irreversible visual field loss. Elevated intraocular pressure (IOP) is the main risk factor for glaucoma. Increased IOP is the result of an imbalance between synthesis and outflow of aqueous humor (AH). Blocking β2 adrenergic receptor (ADRB2) has shown to reduce IOP by decreasing production of AH at the ciliary body (CB). SYL040012 is a siRNA designed to specifically silence ADRB2 currently under development for glaucoma treatment. Here, we show that SYL040012 specifically reduces ADRB2 expression in cell cultures and eye tissues. The compound enters the eye shortly after administration in eye drops and is rapidly distributed among structures of the anterior segment of the eye. In addition, SYL040012 is actively taken up by cells of the CB but not by cells of systemic organs such as the lungs, where inhibition of ADRB2 could cause undesirable side effects. Moreover, SYL040012 reduces IOP in normotensive and hypertensive animal models and the effect appears to be long lasting and extremely well tolerated both locally and systemically.