Pharmacological characterization of a novel 5-hydroxybenzothiazolone-derived b2-adrenoceptor agonist with functional selectivity for anabolic effects on skeletal muscle resulting in a wider cardiovascular safety window in preclinical studies

Copyright ª 2019 by The Author(s) The anabolic effects of b2-adrenoceptor (b2-AR) agonists on skeletal muscle have been demonstrated in various species. However, the clinical use of b2-AR agonists for skeletal muscle wasting conditions has been limited by their undesired cardiovascular effects. Here, we describe the preclinical pharmacological profile of a novel 5-hydroxybenzothiazolone (5-HOB) derived b2-AR agonist in comparison with formoterol as a representative b2-AR agonist that have been well characterized. In vitro, 5-HOB has nanomolar affinity for the human b2-AR and selectivity over the b1-AR and b3-AR. 5-HOB also shows potent agonistic activity at the b2-AR in primary skeletal muscle myotubes and induces hypertrophy of skeletal muscle myotubes. Compared with formoterol, 5-HOB demonstrates comparable full-agonist activity on cAMP production in skeletal muscle cells and skeletal muscle tissue–derived membranes. In contrast, a greatly reduced intrinsic activity was determined in cardiomyocytes and cell membranes prepared from the rat heart. In addition, 5-HOB shows weak effects on chronotropy, inotropy, and vascular relaxation compared with formoterol. In vivo, 5-HOB significantly increases hind limb muscle weight in rats with attenuated effects on heart weight and ejection fraction, unlike formoterol. Furthermore, changes in cardiovascular parameters after bolus subcutaneous treatment in rats and rhesus monkeys are significantly lower with 5-HOB compared with formoterol. In conclusion, the pharmacological profile of 5-HOB indicates superior tissue selectivity compared with the conventional b2-AR agonist formoterol in preclinical studies and supports the notion that such tissue-selective agonists should be investigated for the safe treatment of muscle-wasting conditions without cardiovascular limiting effects

Sacubitril/valsartan (LCZ696) significantly reduces aldosterone and increases cGMP circulating levels in a canine model of RAAS activation

Simultaneous blockade of angiotensin receptors and enhancement of natriuretic peptides (NP) by the first-in-class angiotensin receptor neprilysin (NEP) inhibitor sacubitril/valsartan constitutes an effective approach to treating heart failure. This study examined the effects of sacubitril/valsartan (225 and 675 mg/day) vs. placebo, sacubitril (360 mg/day), valsartan (900 mg/day), and benazepril (5 mg/day) on the dynamics of the renin-angiotensin-aldosterone system (RAAS) and the NP system in dogs. Beagle dogs (n = 18) were fed a low-salt diet (0.05% Na) for 15 days to model RAAS activation observed in clinical heart failure. Drugs were administered once daily during the last 10 days, while the effects on the RAAS and NPs were assessed on Day 1, 5, and 10. Steady-state pharmacokinetics of the test agents were evaluated on Day 5. Compared with placebo, sacubitril/valsartan (675 mg) substantially increased cGMP circulating levels, while benazepril and valsartan showed no effect. Additionally, sacubitril/valsartan (675 mg) and valsartan significantly increased plasma renin activity, angiotensin I and angiotensin II concentrations. Finally, sacubitril/valsartan (both doses), and valsartan significantly decreased plasma aldosterone vs. placebo. Systemic exposure to valsartan following sacubitril/valsartan 675 mg administration was similar to that observed with valsartan 900 mg administration alone. Sacubitril/valsartan favorably modulates the dynamics of the renin and NP cascades through complementary NEP and RAAS inhibition.This is a manuscript of an article published as Mochel, Jonathan P., Chi Hse Teng, Mathieu Peyrou, Jerome Giraudel, Meindert Danhof, and Dean F. Rigel. "Sacubitril/valsartan (LCZ696) significantly reduces aldosterone and increases cGMP circulating levels in a canine model of RAAS activation." European Journal of Pharmaceutical Sciences 128 (2019): 103-111. DOI: 10.1016/j.ejps.2018.11.037. Copyright 2018 Elsevier. Posted with permission

Aldosterone synthase inhibition: cardiorenal protection in animal disease models and translation of hormonal effects to human subjects.

International audienceBackgroundAldosterone synthase inhibition provides the potential to attenuate both the mineralocorticoid receptor-dependent and independent actions of aldosterone. In vitro studies with recombinant human enzymes showed LCI699 to be a potent, reversible, competitive inhibitor of aldosterone synthase (K i¿=¿1.4¿±¿0.2 nmol/L in humans) with relative selectivity over 11ß-hydroxylase.MethodsHormonal effects of orally administered LCI699 were examined in rat and monkey in vivo models of adrenocorticotropic hormone (ACTH) and angiotensin-II-stimulated aldosterone release, and were compared with the mineralocorticoid receptor antagonist eplerenone in a randomized, placebo-controlled study conducted in 99 healthy human subjects. The effects of LCI699 and eplerenone on cardiac and renal sequelae of aldosterone excess were investigated in a double-transgenic rat (dTGR) model overexpressing human renin and angiotensinogen.ResultsRat and monkey in vivo models of stimulated aldosterone release predicted human dose¿ and exposure¿response relationships, but overestimated the selectivity of LCI699 in humans. In the dTGR model, LCI699 dose-dependently blocked increases in aldosterone, prevented development of cardiac and renal functional abnormalities independent of blood pressure changes, and prolonged survival. Eplerenone prolonged survival to a similar extent, but was less effective in preventing cardiac and renal damage. In healthy human subjects, LCI699 0.5 mg selectively reduced plasma and 24 h urinary aldosterone by 49¿±¿3% and 39¿±¿6% respectively (Day 1, mean¿±¿SEM; P¿<¿0.001 vs placebo), which was associated with natriuresis and an increase in plasma renin activity. Doses of LCI699 greater than 1 mg inhibited basal and ACTH-stimulated cortisol. Eplerenone 100 mg increased plasma and 24 h urinary aldosterone while stimulating natriuresis and increasing renin activity. In contrast to eplerenone, LCI699 increased the aldosterone precursor 11-deoxycorticosterone and urinary potassium excretion.ConclusionsThese results provide new insights into the cardiac and renal effects of inhibiting aldosterone synthase in experimental models and translation of the hormonal effects to humans. Selective inhibition of aldosterone synthase appears to be a promising approach to treat diseases associated with aldosterone excess

Chronic measurement of left ventricular pressure in freely moving rats

Measurements of left ventricular pressure (LVP) in conscious freely moving animals are uncommon yet could offer considerable opportunity for understanding cardiovascular disease progression and treatment. The aim of this study was to develop surgical methods and validate the measurements of a new high-fidelity solid-state pressure sensor telemetry device for chronically measuring LVP and dP/dt in rats. The pressure sensor catheter tip (2-Fr) was inserted into the left ventricular chamber through the apex of the heart and the telemeter body implanted in the abdomen. Data was measured up to 85 days after implant. The average daytime dP/dt max was 9444 ±363 mmHg/s, ranging from 7870 to 10558 mmHg/s (n=7). A circadian variation in dP/dt max and heart rate (HR) was observed with an average increase during the night phase in dP/dt max of 918 ±84 mmHg/s and in HR of 38 ±3 bpm. The β-adrenergic-agonist isoproterenol, β1-adrenergic agonist dobutamine, Ca2+ channel blocker verapamil and the calcium sensitizer levosimendan were administered throughout the implant period, inducing dose dependent time course changes and absolute changes in dP/dt max of -6000 to +13,000 mmHg/s . The surgical methods and new technologies demonstrated long term stability, sensitivity to circadian variation and the ability to measure large drug induced changes, validating this new solution for chronic measurement of LVP in conscious rats

Structure-based Design of 4-Hydroxy-3,5-Substituted Piperidines as a New Class of Highly Efficacious Oral Direct Renin Inhibitors

Starting from the cis-configured 3,5-disubstituted piperidine direct renin inhibitor (DRI), (rac)-1, discovered from a target-family-tailored library by high throughput screening (HTS), a structure-based design effort was performed by optimization of both the prime and non-prime site residues flanking the central piperidine transition-state surrogate. This has resulted in analogs with improved potency and pharmacokinetic (PK) properties, and culminated in the identification of the 4-hydroxy-3,5-substituted piperidine, 35 as a development candidate. This compound showed high in vitro potency toward human renin with excellent off-target selectivity, 60% oral bioavailability in rat, and dose-dependent blood pressure lowering effects in the double-transgenic rat model

The Discovery of Novel Potent <i>trans</i>-3,4-Disubstituted Pyrrolidine Inhibitors of the Human Aspartic Protease Renin from in Silico Three-Dimensional (3D) Pharmacophore Searches

The small-molecule <i>trans</i>-3,4-disubstituted pyrrolidine <b>6</b> was identified from in silico three-dimensional (3D) pharmacophore searches based on known X-ray structures of renin–inhibitor complexes and demonstrated to be a weakly active inhibitor of the human enzyme. The unexpected binding mode of the more potent enantiomer (3<i>S</i>,4<i>S</i>)-<b>6a</b> in an extended conformation spanning the nonprime and S1′ pockets of the recombinant human (rh)-renin active site was elucidated by X-ray crystallography. Initial structure–activity relationship work focused on modifications of the hydrophobic diphenylamine portion positioned in S1 and extending toward the S2 pocket. Replacement with an optimized P3–P1 pharmacophore interacting to the nonsubstrate S3^sp cavity eventually resulted in significantly improved in vitro potency and selectivity. The prototype analogue (3<i>S</i>,4<i>S</i>)-<b>12a</b> of this new class of direct renin inhibitors exerted blood pressure lowering effects in a hypertensive double-transgenic rat model after oral administration

Discovery of a Novel Piperidine-Based Inhibitor of Cholesteryl Ester Transfer Protein (CETP) That Retains Activity in Hypertriglyceridemic Plasma

Herein we describe the discovery and characterization of a novel, piperidine-based inhibitor of cholesteryl ester transfer protein (CETP) with a core structure distinct from other reported CETP inhibitors. A versatile synthesis starting from 4-methoxypyridine enabled an efficient exploration of the SAR, giving a lead molecule with potent CETP inhibition in human plasma. The subsequent optimization focused on improvement of pharmacokinetics and mitigation of off-target liabilities, such as CYP inhibition, whose improvement correlated with increased lipophilic efficiency. The effort led to the identification of an achiral, carboxylic acid-bearing compound <b>16</b> (TAP311) with excellent pharmacokinetics in rats and robust efficacy in hamsters. Compared to anacetrapib, the compound showed substantially reduced lipophilicity, had only modest distribution into adipose tissue, and retained potency in hypertriglyceridemic plasma in vitro and in vivo. Furthermore, in contrast to torcetrapib, the compound did not increase aldosterone secretion in human adrenocortical carcinoma cells nor in chronically cannulated rats. On the basis of its preclinical efficacy and safety profile, the compound was advanced into clinical trials