ABSTRACT
The alternative pathway (AP) of the complement system is a key contributor to the pathogenesis of several human diseases including age-related macular degeneration, paroxysmal nocturnal hemoglobinuria (PNH), atypical hemolytic uremic syndrome (aHUS), and various glomerular diseases. The serine protease factor B (FB) is a key node in the AP and is integral to the formation of C3 and C5 convertase. Despite the prominent role of FB in the AP, selective orally bioavailable inhibitors, beyond our own efforts, have not been reported previously. Herein we describe in more detail our efforts to identify FB inhibitors by high-throughput screening (HTS) and leveraging insights from several X-ray cocrystal structures during optimization efforts. This work culminated in the discovery of LNP023 (41), which is currently being evaluated clinically in several diverse AP mediated indications.
Subject(s)
Benzoic Acid/chemistry , Complement Factor B/antagonists & inhibitors , Indoles/chemistry , Atypical Hemolytic Uremic Syndrome/metabolism , Atypical Hemolytic Uremic Syndrome/pathology , Benzoic Acid/metabolism , Benzoic Acid/pharmacokinetics , Binding Sites , Catalytic Domain , Complement Factor B/metabolism , Crystallography, X-Ray , Drug Evaluation, Preclinical , Half-Life , Humans , Indoles/metabolism , Indoles/pharmacokinetics , Inhibitory Concentration 50 , Macular Degeneration/metabolism , Macular Degeneration/pathology , Molecular Dynamics Simulation , Structure-Activity RelationshipABSTRACT
Complement factor D (FD), a highly specific S1 serine protease, plays a central role in the amplification of the alternative complement pathway (AP) of the innate immune system. Dysregulation of AP activity predisposes individuals to diverse disorders such as age-related macular degeneration, atypical hemolytic uremic syndrome, membranoproliferative glomerulonephritis type II, and paroxysmal nocturnal hemoglobinuria. Previously, we have reported the screening efforts and identification of reversible benzylamine-based FD inhibitors (1 and 2) binding to the open active conformation of FD. In continuation of our drug discovery program, we designed compounds applying structure-based approaches to improve interactions with FD and gain selectivity against S1 serine proteases. We report herein the design, synthesis, and medicinal chemistry optimization of the benzylamine series culminating in the discovery of 12, an orally bioavailable and selective FD inhibitor. 12 demonstrated systemic suppression of AP activation in a lipopolysaccharide-induced AP activation model as well as local ocular suppression in intravitreal injection-induced AP activation model in mice expressing human FD.
Subject(s)
Benzylamines/pharmacology , Complement Pathway, Alternative/drug effects , Serine Proteinase Inhibitors/pharmacology , Animals , Benzylamines/chemical synthesis , Benzylamines/metabolism , Binding Sites , Complement Factor D/antagonists & inhibitors , Complement Factor D/chemistry , Complement Factor D/metabolism , Dogs , Drug Design , Humans , Mice, Inbred C57BL , Mice, Transgenic , Molecular Docking Simulation , Protein Conformation , Rats , Serine Proteinase Inhibitors/chemical synthesis , Serine Proteinase Inhibitors/metabolismABSTRACT
Soluble guanylate cyclase (sGC), the endogenous receptor for nitric oxide (NO), has been implicated in several diseases associated with oxidative stress. In a pathological oxidative environment, the heme group of sGC can be oxidized becoming unresponsive to NO leading to a loss in the ability to catalyze the production of cGMP. Recently a dysfunctional sGC/NO/cGMP pathway has been implicated in contributing to elevated intraocular pressure associated with glaucoma. Herein we describe the discovery of molecules specifically designed for topical ocular administration, which can activate oxidized sGC restoring the ability to catalyze the production of cGMP. These efforts culminated in the identification of compound (+)-23, which robustly lowers intraocular pressure in a cynomolgus model of elevated intraocular pressure over 24 h after a single topical ocular drop and has been selected for clinical evaluation.
Subject(s)
Enzyme Activators/chemical synthesis , Enzyme Activators/therapeutic use , Glaucoma/drug therapy , Soluble Guanylyl Cyclase/drug effects , Administration, Ophthalmic , Administration, Topical , Animals , CHO Cells , Cricetinae , Cricetulus , Cyclic GMP/biosynthesis , Drug Discovery , Enzyme Activators/administration & dosage , Humans , Intraocular Pressure/drug effects , Macaca fascicularis , Ophthalmic Solutions , Oxidation-Reduction , RabbitsABSTRACT
A noninvasive topical ocular therapy for the treatment of neovascular or "wet" age-related macular degeneration would provide a patient administered alternative to the current standard of care, which requires physician administered intravitreal injections. This manuscript describes a novel strategy for the use of in vivo models of choroidal neovascularization (CNV) as the primary means of developing SAR related to efficacy from topical administration. Ultimately, this effort led to the discovery of acrizanib (LHA510), a small-molecule VEGFR-2 inhibitor with potency and efficacy in rodent CNV models, limited systemic exposure after topical ocular administration, multiple formulation options, and an acceptable rabbit ocular PK profile.
Subject(s)
Administration, Topical , Indoles/administration & dosage , Pyrazoles/administration & dosage , Pyrimidines/administration & dosage , Vascular Endothelial Growth Factor Receptor-2/antagonists & inhibitors , Wet Macular Degeneration/drug therapy , Animals , Choroidal Neovascularization , Drug Discovery , Indoles/pharmacokinetics , Indoles/therapeutic use , Ophthalmic Solutions , Protein Kinase Inhibitors , Pyrazoles/pharmacokinetics , Pyrazoles/therapeutic use , Pyrimidines/pharmacokinetics , Pyrimidines/therapeutic use , Rabbits , Rodentia , Structure-Activity RelationshipABSTRACT
The epithelial Na+ channel (ENaC) is a key regulator of the volume of airway surface liquid (ASL) and is found in the human airway epithelium. In cystic fibrosis (CF), Na+ hyperabsorption through ENaC, in the absence of cystic fibrosis transmembrane conductance regulator mediated anion secretion, results in the dehydration of respiratory secretions and the impairment of mucociliary clearance. The hypothesis of utilizing an ENaC blocking molecule to facilitate restoration of the airway surface liquid volume sufficiently to allow normal mucociliary clearance is of interest in the management of lung disease in CF patients. This review summarizes the published patent applications from 2014 to the end of 2016 that claim approaches to inhibit the function of ENaC for the treatment of CF.
Subject(s)
Cystic Fibrosis , Cystic Fibrosis Transmembrane Conductance Regulator , Epithelial Sodium Channel Blockers , Epithelial Sodium Channels , Humans , Mucociliary ClearanceABSTRACT
The benefit of intravitreal anti-VEGF therapy in treating wet age-related macular degeneration (AMD) is well established. Identification of VEGFR-2 inhibitors with optimal ADME properties for an ocular indication provides opportunities for dosing routes beyond intravitreal injection. We employed a high-throughput in vivo screening strategy with rodent models of choroidal neovascularization and iterative compound design to identify VEGFR-2 inhibitors with potential to benefit wet AMD patients. These compounds demonstrate preferential ocular tissue distribution and efficacy after oral administration while minimizing systemic exposure.
