A Novel Selective Soluble Guanylate Cyclase Activator, MGV354, Lowers Intraocular Pressure in Preclinical Models, Following Topical Ocular Dosing

Abstract

PURPOSE. The nitric oxide/soluble guanylate cyclase/protein kinase G (NO/sGC/PKG) is known to be involved in the regulation of intraocular pressure (IOP) and may be dysregulated in glaucoma. The purpose is to demonstrate that the sGC activator MGV354 lowers IOP in a monkey model of glaucoma and could be considered as a possible new clinical drug candidate. METHODS.Changes to cGMP were assessed in primary human trabecular meshwork (hNTM) cells and binding studies were conducted using human sGC full-length protein. Ocular safety tolerability, exposure, and efficacy studies were conducted in rabbit and monkey models following topical ocular dosing of MGV354.RESULTS. sGC was highly expressed in the human and cynomolgus monkey outflow pathways. MGV354 had a 7-fold greater Bmax to oxidized sGC compared to that of reduced sGC and generated an 8-to 10-fold greater cGMP compared to that of a reduced condition in hTM cells. A single topical ocular dose with MGV354 caused a significant dose-dependent reduction of 20% to 40% (versus vehicle), lasting up to 6 hours in pigmented rabbits and 24 hours postdose in a cynomolgus monkey model of glaucoma. The MGV354-induced IOP lowering was sustained up to 7 days following once-daily dosing in a monkey model of glaucoma and was greater in magnitude compared to Travatan (travoprost)-induced IOP reduction. Mild to moderate ocular hyperemia was the main adverse effect noted.CONCLUSIONS. MGV354 represents a novel class of sGC activators that can lower IOP in preclinical models of glaucoma. The potential for sGC activators to be used as effective IOPlowering drugs in glaucoma patients could be further determined in clinical studies.Keywords: soluble guanylate cyclase, monkey model of glaucoma, IOP, ODQ, cGMP, glaucoma T he estimated number of glaucoma cases globally is over 60 million, and primary open angle glaucoma accounts for >70% of the total cases. In the United States alone, over 120,000 patients are blind from this disease, accounting for 9% to 12% of all cases of blindness.1 Lowering of intraocular pressure (IOP) is the current gold standard for reducing visual field (VF) loss in glaucoma. However, up to 45% of patients who achieved an IOP-lowering target of 25% to 30% (6 to 8 mm Hg) from baseline IOP by medical treatment continued to show progressive VF loss. Every 1 mm Hg higher mean IOP in the follow-up period was associated with 13% higher risk of progressive VF loss for the study population, whereas each mm Hg reduction was associated with a 10% reduction in disease progression. Rhopressa and latanoprost, which lowered IOP by 1 to 3 mm Hg greater than the monotherapy comparators over 3 months of dosing in patients with glaucoma.5 IOP lowering via the NO/ cGMP signaling pathway is also well known. This is a key pathway in several physiologic processes, including platelet inhibition, smooth muscle relaxation, and neurotransmission. NO is the endogenous ligand of soluble guanylate cyclase (sGC). Binding of NO to the heme domain of sGC results in sGC activation and production ...

Soluble Guanylate Cyclase Stimulators and Activators

“…However, very recently a sGC activator from Novartis (MGV354) was profiled preclinically and clinically in Glaucoma. Despite promising preclinical results in animal models in which MGV354 significantly lowered intraocular pressure (Prasanna et al 2018), MGV354 failed in the phase 1/2 clinical trial (Stacy et al 2018).…”

The nitric oxide-guanylate cyclase pathway and glaucoma

“…A single topical ocular dose caused a significant dose-dependent IOP reduction of 20% to 40% (versus vehicle), lasting up to 6 hours in pigmented rabbits. The MGV354-induced IOP lowering was sustained for up to 7 days following once-daily dosing in a monkey model of glaucoma and was greater in magnitude compared to travoprost-induced IOP reduction 255 . It is not yet clear whether this approach also provides neuroprotection to RGCs beyond that afforded by IOP reduction.…”

“…For example, GC-1 stimulation by IWP-953 increased AqH outflow in enucleated mouse eyes, highlighting the therapeutic potential for GC stimulators as novel ocular hypotensive drugs 142 . Safety, tolerability, and efficacy of the GC activator, MGV354, has shown promising IOP-lowering effects in pigmented rabbits and in a cynomolgus monkey model of glaucoma 255 . A single topical ocular dose caused a significant dose-dependent IOP reduction of 20% to 40% (versus vehicle), lasting up to 6 hours in pigmented rabbits.…”

A Surrogate Matrix-Based Approach Toward Multiplexed Quantitation of an sGC Stimulator and cGMP in Ocular Tissue and Plasma

“…MGV354 was found to lower IOP in rabbit and monkey models although the authors noted a lack of cGMP measurement in ocular tissue as a limitation for their study. 12 Ultimately, the compound could not demonstrate IOP lowering in humans. 13 We hypothesized that administration of an sGC stimulator to the back of the eye could increase cGMP levels and potentially improve blood flow at the back of the eye.…”

“…[7][8][9] The nitric oxide (NO)-soluble guanylate cyclase (sGC)-cGMP pathway has been explored as a potential target to address these underlying risk factors for glaucoma. [10][11][12][13] In this pathway, NO binds to sGC and leads to the production of cGMP, which in turn triggers downstream effects on aqueous humor and blood flow. Our discovery research effort explored the ability of small molecule stimulators to engage sGC to increase cGMP production and potentially improve blood flow at the back of the eye.…”