Structure of the PPARα and -γ Ligand Binding Domain in Complex with AZ 242; Ligand Selectivity and Agonist Activation in the PPAR Family

AbstractBackground: The peroxisome proliferator-activated receptors (PPAR) are ligand-activated transcription factors belonging to the nuclear receptor family. The roles of PPARα in fatty acid oxidation and PPARγ in adipocyte differentiation and lipid storage have been characterized extensively. PPARs are activated by fatty acids and eicosanoids and are also targets for antidyslipidemic drugs, but the molecular interactions governing ligand selectivity for specific subtypes are unclear due to the lack of a PPARα ligand binding domain structure.Results: We have solved the crystal structure of the PPARα ligand binding domain (LBD) in complex with the combined PPARα and -γ agonist AZ 242, a novel dihydro cinnamate derivative that is structurally different from thiazolidinediones. In addition, we present the crystal structure of the PPARγ_LBD/AZ 242 complex and provide a rationale for ligand selectivity toward the PPARα and -γ subtypes. Heteronuclear NMR data on PPARα in both the apo form and in complex with AZ 242 shows an overall stabilization of the LBD upon agonist binding. A comparison of the novel PPARα/AZ 242 complex with the PPARγ/AZ 242 complex and previously solved PPARγ structures reveals a conserved hydrogen bonding network between agonists and the AF2 helix.Conclusions: The complex of PPARα and PPARγ with the dual specificity agonist AZ 242 highlights the conserved interactions required for receptor activation. Together with the NMR data, this suggests a general model for ligand activation in the PPAR family. A comparison of the ligand binding sites reveals a molecular explanation for subtype selectivity and provides a basis for rational drug design

Design of FLAIR:a Phase 2b Study of the 5-Lipoxygenase Activating Protein Inhibitor AZD5718 in Patients With Proteinuric CKD

Introduction: Patients with chronic kidney disease (CKD) remain at risk for kidney and cardiovascular events resulting from residual albuminuria, despite available treatments. Leukotrienes are proinflammatory and vasoconstrictive lipid mediators implicated in the etiology of chronic inflammatory diseases. AZD5718 is a potent, selective, and reversible 5-lipoxygenase activating protein (FLAP) inhibitor that suppresses leukotriene production. Methods: FLAIR (FLAP Inhibition in Renal disease) is an ongoing phase 2b, randomized, double-blind, placebo-controlled, multicenter study to evaluate the efficacy and safety of AZD5718 in patients with proteinuric CKD with or without type 2 diabetes. Participants receive AZD5718 at 3 different doses or placebo once daily for 12 weeks, followed by an 8-week extension in which they also receive dapagliflozin (10 mg/d) as anticipated future standard of care. The planned sample size is 632 participants, providing 91% power to detect 30% reduction in urinary albumin-to-creatinine ratio (UACR) between the maximum dose of AZD5718 and placebo. The dose–response effect of AZD5718 on UACR after the dapagliflozin extension is the primary efficacy objective. Key secondary objectives are the dose–response effect of AZD5718 plus current standard of care on UACR and acute effects of treatment on the estimated glomerular filtration rate. Safety, tolerability, AZD5718 pharmacokinetics, and analyses of biomarkers that may predict or reflect response to AZD5718 are additional objectives. Conclusion: FLAIR will provide data on the effects of 5-lipoxygenase pathway inhibition in patients with proteinuric CKD with or without type 2 diabetes, and will form the basis for future clinical trials (ClinicalTrials.gov: NCT04492722)

The liver X receptor agonist AZ876 protects against pathological cardiac hypertrophy and fibrosis without lipogenic side effects

AimsLiver X receptors (LXRs) transcriptionally regulate inflammation, metabolism, and immunity. Synthetic LXR agonists have been evaluated for their efficacy in the cardiovascular system; however, they elicit prolipogenic side effects which substantially limit their therapeutic use. AZ876 is a novel high-affinity LXR agonist. Herein, we aimed to determine the cardioprotective potential of LXR activation with AZ876. Methods and resultsCardiac hypertrophy was induced in C57Bl6/J mice via transverse aortic constriction (TAC) for 6 weeks. During this period, mice received chow supplemented or not with AZ876 (20 mu mol/kg/day). In murine hearts, LXR protein expression was up-regulated approximate to 7-fold in response to TAC. LXR activation with AZ876 attenuated this increase, and significantly reduced TAC-induced increases in heart weight, myocardial fibrosis, and cardiac dysfunction without affecting blood pressure. At the molecular level, AZ876 suppressed up-regulation of hypertrophy- and fibrosis-related genes, and further inhibited prohypertrophic and profibrotic transforming growth factor (TGF)-Smad2/3 signalling. In isolated cardiac myocytes and fibroblasts, immunocytochemistry confirmed nuclear expression of LXR in both these cell types. In cardiomyocytes, phenylephrine-stimulated cellular hypertrophy was significantly decreased in AZ876-treated cells. In cardiac fibroblasts, AZ876 prevented TGF- and angiotensin II-induced fibroblast collagen synthesis, and inhibited up-regulation of the myofibroblastic marker, -smooth muscle actin. Plasma triglycerides and liver weight were unaltered following AZ876 treatment. ConclusionAZ876 activation of LXR protects from adverse cardiac remodelling in pathological pressure overload, independently of blood pressure. LXR may thus represent a putative molecular target for antihypertrophic and antifibrotic therapies in heart failure prevention

Early Clinical Experience With AZD4831, A Novel Myeloperoxidase Inhibitor, Developed for Patients With Heart Failure With Preserved Ejection Fraction

We evaluated safety, tolerability, pharmacokinetics (PKs), and pharmacodynamics of AZD4831, a novel oral myeloperoxidase (MPO) inhibitor, in a randomized, single‐blind, placebo‐controlled study, following once‐daily multiple ascending dosing to steady‐state in healthy subjects. Target engagement was measured as specific MPO activity in plasma following ex vivo zymosan stimulation of whole blood. Except for generalized maculopapular rash in 4 of 13 subjects receiving the 2 highest doses, 15 and 45 mg AZD4831, no clinically relevant safety and tolerability findings were observed. AZD4831 was rapidly absorbed and plasma concentrations declined slowly with an elimination half‐life of ~ 60 hours. A dose/concentration‐effect relationship between MPO inhibition vs. AZD4831 exposure was established with > 50% MPO inhibition in plasma at concentrations in the low nanomolar range. Steady‐state levels were achieved within 10 days. Taken together, the PK profile, the sustained dose/concentration‐dependent MPO inhibition, and available clinical data support further clinical development of AZD4831 in patients with heart failure with preserved ejection fraction

Safety and efficacy of the 5-lipoxygenase-activating protein inhibitor AZD5718 in patients with recent myocardial infarction : The phase 2a FLAVOUR study

Background: Leukotrienes are pro-inflammatory vasoactive lipid mediators implicated in the pathophysiology of atherosclerotic cardiovascular disease. We studied the effect of the 5-lipoxygenase-activating protein inhibitor AZD5718 on leukotriene biosynthesis and coronary microvascular function in a single-blind, phase 2a study. Methods: Patients 7-28 days after myocardial infarction (+/- ST elevation), with < 50% left anterior descending coronary artery stenosis and Thrombolysis in Myocardial Infarction flow grade >= 2 after percutaneous coronary intervention, were randomized 2:1:2 to once-daily AZD5718 200 mg or 50 mg, or placebo, in 4-and 12-week cohorts. Change in urine leukotriene E-4 (uLTE(4)) was the primary endpoint, and coronary flow velocity reserve (CFVR; via echocardiography) was the key secondary endpoint. Results: Of 129 randomized patients, 128 received treatment (200 mg, n = 52; 50 mg, n = 25; placebo, n = 51). Statistically significant reductions in uLTE4 levels of > 80% were observed in both AZD5718 groups versus the placebo group at 4 and 12 weeks. No significant changes in CFVR were observed for AZD5718 versus placebo. Adverse events (AEs) occurred in 12/18, 3/6 and 6/13 patients receiving 200 mg, 50 mg and placebo, respectively, in the 4-week cohort, and in 27/34, 14/19 and 24/38 patients, respectively, in the 12-week cohort. Serious AEs in seven patients receiving AZD5718 and four receiving placebo were not treatment-related, and there were no deaths. Conclusions: In patients with recent myocardial infarction, AZD5718 was well tolerated, and leukotriene biosynthesis was dose-dependently inhibited. No significant changes in CFVR were detected

Correction to “Discovery of AZD4831, a Mechanism-Based Irreversible Inhibitor of Myeloperoxidase, As a Potential Treatment for Heart Failure with Preserved Ejection Fraction”

Correction to “Discovery of AZD4831, a Mechanism-Based Irreversible Inhibitor of Myeloperoxidase, As a Potential Treatment for Heart Failure with Preserved Ejection Fraction