Pharmacokinetic/pharmacodynamic modeling of roxadustat's effect on LDL cholesterol in patients in Japan with dialysis-dependent chronic kidney disease and anemia.

AIMS: The objective of this analysis was to develop and evaluate a pharmacokinetic/pharmacodynamic (PK/PD) model of the effect of roxadustat on low-density lipoprotein cholesterol (LDL-C) in Japanese patients with anemia of dialysis-dependent chronic kidney disease while considering the impact of covariates on model parameters. METHODS: A total of 2330 LDL-C measurements from 275 patients in 3 clinical studies were analyzed using a nonlinear-mixed effects modeling approach in NONMEM software. RESULTS: The PK/PD relationship between roxadustat exposure and LDL-C was well described by a kinetic-pharmacodynamic model with a physiological indirect response model as the PD component. Co-administered statin usage, sevelamer usage, type of dialysis (hemodialysis or peritoneal dialysis), and sex were selected as covariates for LDLbaseline. Weight was selected as a covariate for ID50. Imax and ID50 were estimated as 0.661 and 1.51 mg/h, respectively. CONCLUSION: Roxadustat can decrease LDL-C independent of statins and sevelamer. Further study of the ability of roxadustat to lower LDL-C and any potential effects on outcomes is needed.

[Roxadustat (Evrenzo® tablet), a therapeutic drug for renal anemia: pharmacological characteristics and clinical evidence in Japan].

Roxadustat (Evrenzo® tablet) is an oral hypoxia-inducible factor prolyl hydroxylase (HIF-PH) inhibitor. Roxadustat has been approved for the treatment of renal anemia in patients on dialysis in September 2019 in Japan. By inhibiting HIF-PH, roxadustat suppresses the degradation of HIF-α, a subunit of the heterodimeric transcription factor HIF, leading to its accumulation and activation of the HIF pathway. Similar to activation of the HIF pathway in response to hypoxia, the production of endogenous erythropoietin is increased and erythropoiesis is stimulated. Moreover, roxadustat stimulates erythropoiesis efficiently by improving iron bioavailability. The efficacy and mechanism of action of roxadustat have been detailed in non-clinical pharmacology studies. Rat models of anemia demonstrated efficacy of roxadustat in correcting anemia and changes in gene expression leading to increased iron bioavailability. Four phase 3 clinical studies in Japan clearly demonstrated the efficacy of roxadustat in patients with renal anemia on dialysis. Roxadustat showed an acceptable safety profile, and the incidences and types of adverse events and serious adverse events reported in the clinical studies were similar with those predicted to occur in these patient population. Since roxadustat is an oral drug, concerns present with erythropoiesis-stimulating agents (ESAs) such as the risk of infection to the medical staff due to accidental needle-stick, pain during ESA injection in patients and burden on patients to visit a hospital, can be avoided or reduced. In November 2020, roxadustat has also been approved for the treatment of renal anemia in patients not on dialysis (data not shown in this article).

Renoprotective effects of the novel prostaglandin EP4 receptor-selective antagonist ASP7657 in 5/6 nephrectomized chronic kidney disease rats.

Prostaglandins (PGs) are important lipid mediators of numerous physiologic and pathophysiologic processes in the kidney. PGE2, the most abundant renal PG, plays a major role in renal physiology, including renin release and glomerular hemodynamics. We investigated the renoprotective properties of the novel PGE2 EP4 receptor-selective antagonist ASP7657 in 5/6 nephrectomized rats, a chronic kidney disease (CKD) model. Eight weeks of repeated administration of ASP7657 (0.001-0.1 mg/kg) dose-dependently and significantly reduced urinary protein excretion and attenuated the development of glomerulosclerosis and tubulointerstitial damage, including fibrosis and inflammatory cell infiltration, without affecting blood pressure. Additionally, ASP7657 tended to have beneficial effects on renal function, as indicated by the decrease in plasma creatinine and blood urea nitrogen levels and attenuation of the decline in creatinine clearance (Ccr). The angiotensin II receptor blocker losartan (10 mg/kg) also showed these renoprotective effects while significantly reducing blood pressure. ASP7657 dose-dependently and significantly reduced the EP4 receptor agonist-induced increase in plasma renin activity, as assessed by angiotensin I release in normal rats. Additionally, ASP7657 attenuated hyperfiltration assessed by Ccr without changing the renal blood flow or blood pressure in diabetic rats. These results suggest that ASP7657 suppresses the progression of chronic renal failure by modulating renin release and improving renal hemodynamics, and may therefore be a promising therapeutic option for inhibiting the progression of CKD.

Pharmacological properties of ASP7657, a novel, potent, and selective prostaglandin EP4 receptor antagonist.

We determined the pharmacologic profile of ASP7657, trans-4-[({[1-(quinolin-2-ylmethyl)-5-(trifluoromethyl)-1H-indol-7 yl] carbonyl} amino) methyl] cyclohexanecarboxylic acid methanesulfonate (1:1), a newly synthesized selective E-type prostaglandin (EP)4 receptor antagonist using several in vitro and in vivo experiments. ASP7657 exhibited high affinity for rat and human EP4 receptors, with Ki values of 6.02 nM and 2.21 nM, respectively. In addition, ASP7657 potently inhibited the PGE2-induced cyclic adenosine monophosphate (cAMP) increase in Chinese hamster ovary (CHO) cells expressing rat EP4 receptors and human lymphoblastoid T (Jurkat) cells, with IC50 values of 0.86 nM and 0.29 nM, respectively. In contrast, ASP7657 did not inhibit the PGE2-induced intracellular calcium increase in HEK293 cells expressing rat EP1 and EP3 receptors, or cAMP increase in CHO cells expressing rat EP2 receptors. ASP7657 showed good pharmacokinetic properties following oral dosing and dose-dependently antagonized the prostaglandin (PG)E2-mediated inhibition of lipopolysaccharide-induced tumor necrosis factor-α release from rat whole blood culture. In addition, 4 weeks repeated oral administration of ASP7657 dose-dependently attenuated albuminuria in type 2 diabetic mice; these effects were significant at doses of 0.01 mg/kg or higher. These results demonstrate that ASP7657 is a potent and selective EP4 receptor antagonist that may be useful in future studies to help clarify the physiological and pathophysiological roles of PG.

Lanosterol synthase mutations cause cholesterol deficiency-associated cataracts in the Shumiya cataract rat.

The Shumiya cataract rat (SCR) is a hereditary cataractous strain. It is thought that the continuous occurrence of poorly differentiated epithelial cells at the bow area of the lens forms the pathophysiological basis for cataract formation in SCRs. In this study, we attempted to identify the genes associated with cataract formation in SCRs by positional cloning. Genetic linkage analysis revealed the presence of a major cataract locus on chromosome 20 as well as a locus on chromosome 15 that partially suppressed cataract onset. Hypomorphic mutations were identified in genes for lanosterol synthase (Lss) on chromosome 20 and farnesyl diphosphate farnesyl transferase 1 (Fdft1) on chromosome 15, both of which function in the cholesterol biosynthesis pathway. A null mutation for Lss was also identified. Cataract onset was associated with the specific combination of Lss and Fdft1 mutant alleles that decreased cholesterol levels in cataractous lenses to about 57% of normal. Thus, cholesterol insufficiency may underlie the deficient proliferation of lens epithelial cells in SCRs, which results in the loss of homeostatic epithelial cell control of the underlying fiber cells and eventually leads to cataractogenesis. These findings may have some relevance to other types of cataracts, inborn defects of cholesterol synthesis, and the effects of cholesterol-lowering medication.

Characterization of the pharmacology of YM-198313 on volume-regulated anion channels.

Activation of the volume-regulated anion channels (VRAC) is considered to be involved in arrhythmia, but it has not yet been fully elucidated because of the lack of its high affinitive and selective compounds. A newly synthesized compound, YM-198313 (sodium 4-({[2-(methylthio)benzyl]amino}-5-[(1-phenylethyl)thio]isothiazol-3-olate), strongly inhibited VRAC in HeLa cells with an IC50 of 3.03+/-0.05 microM. However, YM-198313 weakly affected both the Ca2+-activated Cl- channels in HTC cells and the cAMP-activated Cl- channels in T84 cells, demonstrating that this compound is selective for VRAC among Cl- channels. At 10 microM, YM-198313 almost completely (100+/-7.8%) inhibited the VRAC current in guinea pig atrial myocytes. However, at the same concentration, YM-198313 showed little inhibitory effect on the cardiac cation currents in ventricular myocytes. We believe that YM-198313 is a potent and selective VRAC inhibitor, therefore, it should be use to clarify the role VRAC plays in arrhythmia.

Synthesis and biological evaluation of novel propylamine derivatives as orally active squalene synthase inhibitors.

Squalene synthase inhibitors are potentially superior hypolipidemic agents. We synthesized novel propylamine derivatives, as well as evaluated their ability to inhibit squalene synthase and their lipid-lowering effects in rats. 1-Allyl-2-[3-(benzylamino)propoxy]-9H-carbazole (YM-75440) demonstrated potent inhibition of the enzyme derived from HepG2 cells with an IC(50) value of 63 nM. It significantly reduced both plasma total cholesterol and plasma triglyceride levels following oral dosing to rats with a reduced tendency to elevate plasma transaminase levels.

Synthesis and biological evaluation of quinuclidine derivatives incorporating phenothiazine moieties as squalene synthase inhibitors.

Squalene synthase inhibitors have the potential to be superior hypocholesterolemic agents. A series of quinuclidine derivatives incorporating phenothiazine systems was synthesized in order to investigate the effects of their structure on the inhibition of hamster liver microsomal enzyme. (+/-)-3-(10-Methyl-10H-phenothiazin-3-ylmethoxy)quinuclidine hydrochloride (19) was the most potent inhibitor in this series with an IC(50) value of 0.12 microM. Oral dosing of compound 19 to hamsters demonstrated effective reduction of both plasma total cholesterol levels and plasma triglyceride levels. Compound 19 showed a reduced tendency to elevate plasma transaminase levels, an indicator of hepatotoxicity. Enantiomerically pure (-)-19, YM-53546, was found to be more potent than the corresponding (+)-enantiomer.

Syntheses of 3-ethylidenequinuclidine derivatives as squalene synthase inhibitors. Part 2: enzyme inhibition and effects on plasma lipid levels.

Squalene synthase (E.C. 2.5.1.21) is a microsomal enzyme which catalyzes the reductive dimerization of two molecules of farnesyl diphosphate to form squalene, and is involved in the first committed step in cholesterol biosynthesis. It is an attractive target for hypocholesterolemic and hypotriglyceridemic strategies. We synthesized a series of 3-ethylidenequinuclidine derivatives, and evaluated their ability to inhibit squalene synthase in vitro and to lower non-HDL cholesterol levels in hamsters. 3-Ethylidenequinuclidine derivatives incorporating an unsubstituted 9H-carbazole moiety reduced plasma non-HDL cholesterol levels and did not affect plasma transaminase levels, indicating a lack of hepatotoxicity. Among the novel compounds, (Z)-2-[2-(quinuclidin-3-ylidene)ethoxy]-9H-carbazole hydrochloride 8 (YM-53579) and (E)-2-[2-fluoro-2-(quinuclidin-3-ylidene)ethoxy]-9H-carbazole hydrochloride 28 (YM-53601) were potent inhibitors of squalene synthase derived from human hepatoma cells, with IC(50) values of 160 and 79 nM, respectively. They also reduced plasma non-HDL cholesterol levels in hamsters by approximately 50 and 70%, respectively, at an oral dose of 50 mg/kg/day for 5 days.

YM-53601, a novel squalene synthase inhibitor, suppresses lipogenic biosynthesis and lipid secretion in rodents.

1. To better understand how it decreases plasma cholesterol and triglyceride levels, we evaluated the effect of (E)-2-[2-fluoro-2-(quinuclidin-3-ylidene)ethoxy]-9H-carbazole monohydrochloride(YM-53601) on lipogenic biosynthesis in the liver and lipid secretion from the liver in rats and hamsters. 2. Single administration of YM-53601 in cholestyramine-treated rats inhibited triglyceride and free fatty acid (FFA) biosynthesis at a similar dose range to that at which it inhibited cholesterol biosynthesis. YM-53601 inhibited both triglyceride and FFA biosynthesis in hamsters treated with cholestyramine. 3. YM-53601 by single oral administration decreased the enhanced plasma triglyceride levels in hamsters induced by an injection of protamine sulfate, which inhibits lipoprotein lipase (LPL) and consequently increases plasma very low-density lipoprotein (VLDL) triglyceride levels. YM-53601 also decreased the enhanced plasma triglyceride and cholesterol levels in hamsters treated with Triton WR1339, which also inhibits the degradation of VLDL. Plasma cholesterol was significantly decreased as soon as 1 h after single administration of YM-53601 in hamsters fed a normal diet. 4. This is the first report that a squalene synthase inhibitor suppresses lipogenic biosynthesis in the liver and cholesterol and triglyceride secretion from the liver in vivo. We therefore suggest that the mechanism by which YM-53601 decreases plasma triglyceride might include these effects. The finding that YM-53601 rapidly decreased plasma cholesterol suggests that this compound may be effective in decreasing plasma cholesterol levels early in the course of treatment of hypercholesterolemia in humans.

Syntheses and biological evaluation of novel quinuclidine derivatives as squalene synthase inhibitors.

Squalene synthase (E.C. 2.5.1.21) catalyses the reductive dimerization of two molecules of farnesyl diphosphate to form squalene and is involved in the first committed step in cholesterol biosynthesis. Inhibition of this enzyme is therefore an attractive target for hypocholesterolemic strategies. A series of quinuclidine derivatives incorporating a tricyclic system was synthesized and evaluated for their ability to inhibit squalene synthase in vitro. A 9H-fluorene moiety was found to be optimal as the tricyclic system for potent inhibitory activity. Improved activity can be achieved with a conformationally constrained three-atom linkage connecting the tricyclic system with the quinuclidine nucleus. Among these compounds, (Z)-3-[2-(9H-fluoren-2-yloxy)ethylidene]-quinuclidine hydrochloride 31 was found to be a potent inhibitor of squalene synthase derived from hamster liver and human hepatoma cells with IC(50) values of 76 and 48 nM, respectively. Oral dosing of compound 31 demonstrated effective reduction of plasma non-HDL cholesterol levels in hamsters.

Effect of YM-53601, a novel squalene synthase inhibitor, on the clearance rate of plasma LDL and VLDL in hamsters.

1. To better understand how it decreases plasma cholesterol and triglyceride, we evaluated the effect of YM-53601 ((E-2-[2-fluoro-2-(quinuclidin-3-ylidene) ethoxy]-9H-carbozole monohydrochloride) on the clearance rate of low density lipoprotein (LDL) and very low density lipoprotein (VLDL) in hamsters. 2. Treatment with YM-53601 at 50 mg kg(-1) for 5 days in hamsters fed a normal diet enhanced the disappearance of 1,1'-Dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI)-VLDL and DiI-LDL. This effect on DiI-LDL was lost in the early phase after DiI-methyl(met)-LDL, chemically modified to block LDL receptor binding, was injected in hamsters, but was retained in the late phase. Pre-treatment with protamine sulphate, which inhibits the activity of LPL, also failed to enhance DiI-VLDL clearance rate by YM-53601. 3. Even on single oral administration at 30 mg kg(-1), YM-53601 enhanced the disappearance of the high concentration of plasma triglyceride after injection of intrafat, an emulsion of fat. Plasma triglyceride was significantly decreased as soon as 1 h after single administration of YM-53601 in hamsters fed a normal diet. 4. These results indicate that the decrease in plasma total cholesterol and triglyceride after the treatment with YM-53601 is due to its enhancement of the clearance rate of LDL and VLDL, respectively. Moreover, YM-53601 may be effective in decreasing plasma triglyceride levels early in the course of treatment of hypertriglyceridaemia in humans.

Experimental model of escape phenomenon in hamsters and the effectiveness of YM-53601 in the model.

1. The aim of this study was to establish an experimental model of the escape phenomenon, in which plasma cholesterol, initially reduced by a 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase inhibitor such as pravastatin, increases again on long-term administration. We also evaluated the efficacy of YM-53601 ((E)-2-[2-fluoro-2- (quinuclidin-3-ylidene) ethoxy]-9H-carbazole monohydrochloride), a squalene synthase inhibitor, in this model. 2. Pravastatin inhibited cholesterol biosynthesis in hamster primary hepatocytes (IC(50), 14 nM). After pre-treatment with pravastatin, in contrast, almost no effect on cholesterol biosynthesis was seen. 3. In hamsters fed a high fat diet, 3 mg kg(-1) pravastatin for 9 days decreased plasma non-HDL cholesterol (total cholesterol - high density lipoprotein cholesterol) (P<0.01), but this effect was lost between 17 and 27 days of treatment, accompanied by an increase in HMG-CoA reductase activity. No such increase in plasma non-HDL cholesterol was seen with YM-53601 at 30 mg kg(-1) after 9 (P<0.001), 17 (P<0.01) or 27 (P<0.001) days of treatment. Replacement of pravastatin with YM-53601 caused a decrease in plasma non-HDL cholesterol by 53% (P<0.001) and in HMG-CoA reductase activity. 4. This animal model thus satisfactorily replicates the escape phenomenon observed in humans and may therefore be useful in evaluation of lipid-lowering agents, specifically comparison of HMG-CoA reductase inhibitors. Further, YM-53601 may be useful in the treatment of hypercholesterolemia without induction of the escape phenomenon.