Pharmacological Characterization of IW-1973, a Novel Soluble Guanylate Cyclase Stimulator with Extensive Tissue Distribution, Antihypertensive, Anti-Inflammatory, and Antifibrotic Effects in Preclinical Models of Disease

Jenny Tobin ,Jaime L Masferrer,Sheila Ranganath,Ali R Banijamali,Courtney Shea,Sylvie G Bernier,Sarah Jacobson,Kim Long,Mark G Currie,G-Yoon Jamie Im,Renee Sarno,G Todd Milne,Peter Germano,Albert T Profy,Daniel P Zimmer,Guang Liu,James Wakefield,Kim San Tang ,Joy S Miyashiro ,Joel Moore ,Kristine A Sykes ,James E Sheppeck

doi:10.1124/jpet.117.247429

Abstract

Soluble guanylate cyclase (sGC), a key signal-transduction enzyme, increases the conversion of guanosine-5'-triphosphate to cGMP upon binding of nitric oxide (NO). Endothelial dysfunction and/or reduced NO signaling have been implicated in cardiovascular disease pathogenesis and complications of diabetes and have been associated with other disease states and aging. Soluble guanylate cyclase (sGC) stimulators are small-molecule drugs that bind sGC and enhance NO-mediated cGMP signaling. The pharmacological characterization of IW-1973 [1,1,1,3,3,3-hexafluoro-2-(((5-fluoro-2-(1-(2-fluorobenzyl)-5-(isoxazol-3-yl)-1H-pyrazol-3-yl) pyrimidin-4-yl)amino)methyl)propan-2-ol], a novel clinical-stage sGC stimulator under clinical investigation for treatment of heart failure with preserved ejection fraction and diabetic nephropathy, is described. In the presence of NO, IW-1973 stimulated sGC in a human purified enzyme assay and a HEK-293 whole cell assay. sGC stimulation by IW-1973 in cells was associated with increased phosphorylation of vasodilator-stimulated phosphoprotein. IW-1973, at doses of 1-10 mg/kg, significantly lowered blood pressure in normotensive and spontaneously hypertensive rats. In a Dahl salt-sensitive hypertension model, IW-1973 significantly reduced blood pressure, inflammatory cytokine levels, and renal disease markers, including proteinuria and renal fibrotic gene expression. The results were affirmed in mouse lipopolysaccharide-induced inflammation and rat unilateral ureteral obstruction renal fibrosis models. A quantitative whole-body autoradiography study of IW-1973 revealed extensive tissue distribution and pharmacokinetic studies showed a large volume of distribution and a profile consistent with predicted once-a-day dosing in humans. In summary, IW-1973 is a potent, orally available sGC stimulator that exhibits renoprotective, anti-inflammatory, and antifibrotic effects in nonclinical models.

Highlights

Soluble guanylate cyclase is the major receptor for nitric oxide (NO) and a key signal-transduction enzyme in the NO-cGMP signaling pathway
IW-1973 is a Soluble guanylate cyclase (sGC) stimulator from a novel pyrazolopyrimidine heterocyclic structural class (Fig. 1A)
At a concentration of 30 mM, IW-1973 alone increased cGMP 6-fold from baseline to a mean of 303 nM

Summary

Introduction

Soluble guanylate cyclase (sGC) is the major receptor for nitric oxide (NO) and a key signal-transduction enzyme in the NO-cGMP signaling pathway. In response to vascular shear stress, endothelial NO synthase produces NO, which activates sGC present in neighboring vascular smooth muscle cells (Moncada and Higgs, 2006) This results in vasodilation and a concomitant increase in local blood flow (Moncada and Higgs, 2006). SGC stimulators are heme dependent, and importantly act in synergy with NO to increase cGMP production (Follmann et al, 2013) In this way, sGC stimulators preserve spatiotemporal control of endogenous NO signaling. The mechanism of action of sGC stimulators contrasts with sGC activators, which are heme independent and do not act in synergy with NO to increase cGMP (Follmann et al, 2013). We describe the pharmacology of IW-1973 [1,1,1,3,3,3-hexafluoro-2-(((5-fluoro2-(1-(2-fluorobenzyl)-5-(isoxazol-3-yl)-1H-pyrazol-3-yl) pyrimidin-4-yl)amino)methyl)propan-2-ol], a novel sGC stimulator in clinical development with potential as a treatment of a broad range of diseases

Materials and Methods

Results

Discussion