ABSTRACT
Effective treatments for neurodegenerative diseases remain elusive and are critically needed since the burden of these diseases increases across an aging global population. Nitric oxide (NO) is a gasotransmitter that binds to soluble guanylate cyclase (sGC) to produce cyclic guanosine monophosphate (cGMP). Impairment of this pathway has been demonstrated in neurodegenerative diseases. Normalizing deficient NO-cGMP signaling could address multiple pathophysiological features of neurodegenerative diseases. sGC stimulators are small molecules that synergize with NO, activate sGC, and increase cGMP production. Many systemic sGC stimulators have been characterized and advanced into clinical development for a variety of non-central nervous system (CNS) pathologies. Here, we disclose the discovery of CY6463, the first brain-penetrant sGC stimulator in clinical development for the treatment of neurodegenerative diseases, and demonstrate its ability to improve neuronal activity, mediate neuroprotection, and increase cognitive performance in preclinical models. In several cellular assays, CY6463 was demonstrated to be a potent stimulator of sGC. In agreement with the known effects of sGC stimulation in the vasculature, CY6463 elicits decreases in blood pressure in both rats and mice. Relative to a non-CNS penetrant sGC stimulator, rodents treated with CY6463 had higher cGMP levels in cerebrospinal fluid (CSF), functional-magnetic-resonance-imaging-blood-oxygen-level-dependent (fMRI-BOLD) signals, and cortical electroencephalographic (EEG) gamma-band oscillatory power. Additionally, CY6463 improved cognitive performance in a model of cognitive disruption induced by the administration of a noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist. In models of neurodegeneration, CY6463 treatment increased long-term potentiation (LTP) in hippocampal slices from a Huntington's disease mouse model and decreased the loss of dendritic spines in aged and Alzheimer's disease mouse models. In a model of diet-induced obesity, CY6463 reduced markers of inflammation in the plasma. Furthermore, CY6463 elicited an additive increase in cortical gamma-band oscillatory power when co-administered with donepezil: the standard of care in Alzheimer's disease. Together, these data support the clinical development of CY6463 as a novel treatment for neurodegenerative disorders.
ABSTRACT
Soluble guanylate cyclase (sGC) is a clinically validated therapeutic target in the treatment of pulmonary hypertension. Modulators of sGC have the potential to treat diseases that are affected by dysregulation of the NO-sGC-cGMP signal transduction pathway. This letter describes the SAR efforts that led to the discovery of CYR715, a novel carboxylic acid-containing sGC stimulator, with an improved metabolic profile relative to our previously described stimulator, IWP-051. CYR715 addressed potential idiosyncratic drug toxicity (IDT) liabilities associated with the formation of reactive, migrating acyl glucuronides (AG) found in related carboxylic acid-containing analogs and demonstrated high oral bioavailability in rat and dose-dependent hemodynamic pharmacology in normotensive Sprague-Dawley rats.
Subject(s)
Carboxylic Acids/chemistry , Glucuronides/chemistry , Hypertension, Pulmonary/drug therapy , Soluble Guanylyl Cyclase/metabolism , Vasodilator Agents/chemistry , Administration, Oral , Animals , Dose-Response Relationship, Drug , Drug Evaluation, Preclinical , Glucuronides/administration & dosage , Glucuronides/pharmacokinetics , Humans , Male , Metabolome , Models, Molecular , Nitric Oxide/metabolism , Oxidative Stress/drug effects , Protein Binding , Rats, Sprague-Dawley , Signal Transduction , Structure-Activity Relationship , Vasodilator Agents/administration & dosage , Vasodilator Agents/pharmacokineticsABSTRACT
In recent years, soluble guanylate cyclase (sGC, EC 4.6.1.2) has emerged as an attractive therapeutic target for treating cardiovascular diseases and diseases associated with fibrosis and end-organ failure. Herein, we describe our design and synthesis of a series of 4-hydroxypyrimidine sGC stimulators starting with an internally discovered lead. Our efforts have led to the discovery of IWP-051, a molecule that achieves good alignment of potency, stability, selectivity, and pharmacodynamic effects while maintaining favorable pharmacokinetic properties with once-daily dosing potential in humans.
