This chapter focuses on pharmaceutically acceptable antagonist that would interact with the putative lipopolysaccharide (LPS) receptor on the cell surface and block the action of LPS without demonstrating any "LPS-like" cellular activation on its own. Synthetic endotoxin antagonists are structurally based on natural lipid A and the biosynthetic precursors. The decrease in activity from this last alteration is proposed to be due to the steric bulk of this modification, thus causing a drastic conformational change in the molecule, and due to the electronics at the C-4 position. Since the structure of lipid IVA presents a synthetically simpler disaccha-ride, the investigation into the feasibility of using this biosynthetic intermediate began as a lead structure. Bacterial infection can be life-threatening, requiring that a potential host organism be highly diligent in maintaining its antimicrobial "state of awareness." Endotoxin or LPS is an integral component of the outer membrane of gram-negative bacteria.

There is a pressing need to develop alternatives to annual influenza vaccines and antiviral agents licensed for mitigating influenza infection. Previous studies reported that acute lung injury caused by chemical or microbial insults is secondary to the generation of host-derived, oxidized phospholipid that potently stimulates Toll-like receptor 4 (TLR4)-dependent inflammation. Subsequently, we reported that Tlr4(-/-) mice are highly refractory to influenza-induced lethality, and proposed that therapeutic antagonism of TLR4 signalling would protect against influenza-induced acute lung injury. Here we report that therapeutic administration of Eritoran (also known as E5564)-a potent, well-tolerated, synthetic TLR4 antagonist-blocks influenza-induced lethality in mice, as well as lung pathology, clinical symptoms, cytokine and oxidized phospholipid expression, and decreases viral titres. CD14 and TLR2 are also required for Eritoran-mediated protection, and CD14 directly binds Eritoran and inhibits ligand binding to MD2. Thus, Eritoran blockade of TLR signalling represents a novel therapeutic approach for inflammation associated with influenza, and possibly other infections.

IMPORTANCE:Eritoran is a synthetic lipid A antagonist that blocks lipopolysaccharide (LPS) from binding at the cell surface MD2-TLR4 receptor. LPS is a major component of the outer membrane of gram-negative bacteria and is a potent activator of the acute inflammatory response.OBJECTIVE:To determine if eritoran, a TLR4 antagonist, would significantly reduce sepsis-induced mortality.DESIGN, SETTING, AND PARTICIPANTS:We performed a randomized, double-blind, placebo-controlled, multinational phase 3 trial in 197 intensive care units. Patients were enrolled from June 2006 to September 2010 and final follow-up was completed in September 2011.INTERVENTIONS:Patients with severe sepsis (n = 1961) were randomized and treated within 12 hours of onset of first organ dysfunction in a 2:1 ratio with a 6-day course of either eritoran tetrasodium (105 mg total) or placebo, with n = 1304 and n = 657 patients, respectively.MAIN OUTCOME MEASURES:The primary end point was 28-day all-cause mortality. The secondary end points were all-cause mortality at 3, 6, and 12 months after beginning treatment.RESULTS:Baseline characteristics of the 2 study groups were similar. In the modified intent-to-treat analysis (randomized patients who received at least 1 dose) there was no significant difference in the primary end point of 28-day all-cause mortality with 28.1% (366/1304) in the eritoran group vs 26.9% (177/657) in the placebo group (P = .59; hazard ratio, 1.05; 95% CI, 0.88-1.26; difference in mortality rate, -1.1; 95% CI, -5.3 to 3.1) or in the key secondary end point of 1-year all-cause mortality with 44.1% (290/657) in the eritoran group vs 43.3% (565/1304) in the placebo group, Kaplan-Meier analysis of time to death by 1 year, P = .79 (hazard ratio, 0.98; 0.85-1.13). No significant differences were observed in any of the prespecified subgroups. Adverse events, including secondary infection rates, did not differ between study groups.CONCLUSIONS AND RELEVANCE:Among patients with severe sepsis, the use of eritoran, compared with placebo, did not result in reduced 28-day mortality.TRIAL REGISTRATION:clinicaltrials.gov Identifier: NCT00334828.

Eritoran, a synthetic analogue of lipid A, has been shown to bind to TLR4/MD-2 complex and thereby block the interaction of endotoxins with TLR4. We report here the results of a study conducted to assess the single-dose safety and tolerability, as well as the pharmacokinetics and pharmacodynamics, of eritoran infusion in Japanese and Caucasian healthy adult men. Sixty-four men (aged 20–45 years; body mass index 18–30 kg/m2) were randomized into four groups: 4-mg total dose (six Japanese and six Caucasian men); 12-mg total dose (12 Japanese and 12 Caucasian men); 28-mg total dose (six Japanese and six Caucasian men); and placebo (eight Japanese and eight Caucasian men). Eritoran in single doses up to 28 mg over 4 h was well tolerated, with no apparent ethnic differences noted. Plasma concentrations were slightly higher in Japanese versus Caucasian men; these differences were not significant after adjustment for differences in body mass (clearance: approximately 1.2 ml/h/kg; volume of distribution at steady state: approximately 0.07 l/kg). The ex vivo endotoxin inhibitory activity of eritoran was similar in Japanese and Caucasian men. The data do not indicate any need for clinical dose adjustment for possible ethnic-based differences in drug distribution or metabolism.

Purpose: This phase I study was conducted to characterize the safety profile, pharmacokinetics, pharmacodynamics, dose-limiting toxicity (DLT), and the maximum-tolerated dose of E7820, a novel oral sulfonamide derivative with antiangiogenic properties, when administered to patients with advanced solid malignancies. Patients and Methods: Patients received single daily doses of E7820 orally for 28 days in cycle 1, followed by a 7-day no-treatment period, after which time-uninterrupted daily dosing ensued. The starting dose of E7820 was 10 mg/d, which was increased to 20, 40, 70, 100, and 200 mg/d in cohorts of new patients. Results: Thirty-seven patients [21 male; median age 65 (40–82] were enrolled. At 100 mg/d, 1 patient experienced a DLT consisting of grade 3 neutropenia, thrombocytopenia, and elevated liver enzymes. At the 200-mg dose level, 2 patients experienced grade 4 thrombocytopenia and neutropenia. No partial or complete responses were observed; 8 patients had stable disease (≥4 months), including 5 patients with protracted stable disease exceeding 6 months. Mean time to maximum plasma concentration values ranged from 1 to 12 hours, whereas mean terminal half-life values ranged from 5.6 to 8.6 hours. Flow cytometric analysis of platelet integrin α-2 expression showed a sustained greater than 50% decrease beyond day 28 in 3 of 4 patients at 200 mg, whereas moderate (<30%) decreases were observed at 70- and 100-mg dose levels. Conclusions: The recommended phase II dose of E7820 is 100 mg/d, based on a fasting schedule. E7820 downregulates integrin α-2 expression in surrogate tissues (platelets) and is associated with stable disease in a wide variety of heavily pretreated malignancies. Clin Cancer Res; 17(1); 193–200. ©2011 AACR.

Activation of TLR4 signaling by endotoxin is believed to be a primary mediator of sepsis and septic shock, via excessive production of cytokines and proinflammatory mediators [1]. Eritoran tetrasodium (hereafter eritoran), a synthetic analog of the endotoxin constituent lipid A, binds to the TLR4/MD-2 complex and thereby blocks the interaction of endotoxin with TLR4 [2]. Eritoran is being investigated for the treatment of severe sepsis [3]. We report results of a study conducted to assess the single-dose safety and tolerability, as well as pharmacokinetics and pharmacodynamics, of eritoran infusion in Japanese and Caucasian healthy adult males.

Numerous studies have suggested that oral supplementation with resveratrol exerts cardioprotective effects, but evidence of the effects on C-reactive protein (CRP) plasma levels and other cardiovascular (CV) risk factors is inconclusive. Therefore, we performed a meta-analysis to evaluate the efficacy of resveratrol supplementation on plasma CRP concentrations and selected predictors of CV risk.The search included PUBMED, Cochrane Library, Web of Science, Scopus, and EMBASE (up to August 31, 2014) to identify RCTs investigating the effects of resveratrol supplementation on selected CV risk factors. Quantitative data synthesis was performed using a random-effects model, with weighted mean difference (WMD) and 95% confidence intervals (CI) as summary statistics.Meta-analysis of data from 10 RCTs (11 treatment arms) did not support a significant effect of resveratrol supplementation in altering plasma CRP concentrations (WMD: − 0.144 mg/L, 95% CI: − 0.968–0.680, p = 0.731). Resveratrol supplementation was not found to alter plasma levels of total cholesterol (WMD: 1.49 mg/dL, 95% CI: − 14.96–17.93, p = 0.859), low density lipoprotein cholesterol (WMD: − 0.31 mg/dL, 95% CI: − 9.57–8.95, p = 0.948), triglycerides (WMD: 2.67 mg/dL, 95% CI: − 28.34–33.67, p = 0.866), and glucose (WMD: 1.28 mg/dL, 95% CI: − 5.28–7.84, p = 0.703). It also slightly reduced high density lipoprotein cholesterol concentrations (WMD: − 4.18 mg/dL, 95% CI: − 6.54 to − 1.82, p = 0.001). Likewise, no significant effect was observed on systolic (WMD: 0.82 mm Hg, 95% CI: − 8.86–10.50, p = 0.868) and diastolic blood pressure (WMD: 1.72 mm Hg, 95% CI: − 6.29–9.73, p = 0.674).This meta-analysis of available RCTs does not suggest any benefit of resveratrol supplementation on CV risk factors. Larger, well-designed trials are necessary to confirm these results.

3537 Background: In vitro,E7820, inhibits α2-integrin expression, endothelial cell proliferation, and vascular tube formation. In colorectal cancer xenograft models, the combination of E7820 and cetuximab demonstrated additive antitumor activity. Methods: This phase II study evaluates the combination of E7820 and cetuximab in subjects with refractory mCRC. A phase Ib study established the maximum tolerated dose of E7820 (100 mg qd po) with cetuximab (400 mg/m2 iv Day 8/Cycle 1, followed by 250 mg/m2 weekly) to be administered in this study (JCO. 2008;26[May 20 suppl]; Abstr 3568). There were 28 evaluable subjects (ECOG 0-1) who relapsed following ≤ 3 prior regimens including 5 subjects from the phase Ib study. The primary endpoint was objective response rate. Results: A mean of 3 cycles (range, 1-13+) were administered. One case each of grade 4 pleuritic pain and pulmonary embolism were observed. E7820 related-grade 3 toxicities included increased AST (3/28, 11%), increased ALT (2/28, 7%), and diarrhea, hypomagnesemia, decreased glomerular filtration rate and elevated creatinine (1/28, 3% in each). E7820-related grade 2 toxicities (> 2 subjects) included anorexia, fatigue, dermatitis acneiform, diarrhea, increased ALT and headache. There were no treatment-related deaths. α2-Integrin levels (18 subjects) decreased over the first month to 81.5% of baseline levels (p = 0.0074) without significant changes in platelet function. Treatment outcomes: objective response rate (ORR = 3.6%), clinical benefit rate (CBR = 14.3%), median progression-free survival (PFS=1.9 mo) and median overall survival (OS = 9.6 mo). Kras mutations were detected in 7/15 (47%) tumor samples available for analysis; among this group, one PR was observed and continues for > 13 cycles. Conclusions: E7820 combined with cetuximab is well-tolerated in subjects with refractory mCRC. This study did not meet its primary endpoint. The single prolonged PR observed in a subject with mutated Kras may indicate possible activity of the E7820 and cetuximab combination in this subset of patients and will require additional confirmatory studies. Author Disclosure Employment or Leadership Position Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Eisai

Background: Eritoran tetrasodium (E5564), a structural analogue of the lipid A portion of endotoxin (lipopolysaccharide or LPS), is an antagonist of LPS and other Toll-like receptor 4 (TLR4) ligands. Eritoran tetrasodium quantitatively blocks LPS response in vivo in animal and human endotoxemia models and demonstrates a long pharmacokinetic half-life, but a short pharmacodynamic half-life. The objective of this study was to assess the safety, and pharmacokinetic and pharmacodynamic profile of E5564 infused twice-daily at three target steady-state plasma levels of approximately 1, 3 and 10 µg/ml in healthy volunteers. Results: Loading and maintenance doses of up to 77 mg over 3 days in females and 105 mg over 6 days in males were safe and well-tolerated except for self-limiting phlebitis at the drug infusion site. Plasma levels reached steady state by 24 h. The Cmax, Cmin, and C88, AUC0 —∞ were dose proportional and gender independent. Pharmacodynamic activity measured by an ex vivo LPS challenge assay, demonstrated dose-dependence for both E5564 and LPS and plasma levels of ~3 µg/ml E5564 or greater blocked up to 1 ng/ml LPS. Conclusions: Every 12-h dosing of E5564 can replace continuous infusion, while maintaining uninterrupted blocking of high-dose LPS.

Purpose. Eritoran (E5564) is a glycophospholipid that acts as a toll-like receptor 4 (TLR4) antagonist that is being tested as a treatment for severe sepsis and septic shock. In the blood, eritoran binds to plasma lipoproteins altering its pharmacokinetic and pharmacodynamic (PD) effects in vivo. The purpose of this study was to determine the influence of changes in plasma cholesterol and triglyceride concentrations on the plasma pharmacokinetics and ex vivo activity of eritoran following single intravenous bolus dosing of eritoran to healthy female rabbits fed either a regular chow diet or a cholesterol-enriched diet. This was done with eritoran administered as stable micelle formulations of mean hydrodynamic diameters of 8 or 27 nm).Methods. Female New Zealand White rabbits were fed a standard diet for 7 days and then randomly assigned either a regular chow diet [regular-diet (n=9)] or a cholesterol-enriched diet [cholesterol-diet (n=12)] for an additional 7 days. Following feeding of these diets a single intravenous bolus dose of eritoran (0.5 mg/kg) formulated into either "small micelles" (8 nm in diameter) or "large micelles" (27 nm in diameter) was administered to regular-fed and cholesterol-fed rabbits. Serial blood samples were obtained prior to eritoran administration and at the following times post injection: 0.083 (5 min), 1, 2, 4, 8, 10, 24, 48 and 72 h. Plasma was analyzed for eritoran concentrations using LC/MS/MS. Total plasma cholesterol (TC) and triglyceride (TG) levels were quantified using enzymatic kits. Plasma eritoran pharmacokinetic (PK) parameters were estimated by non-compartmental analysis using the WinNonlin nonlinear estimation program. To analyze PD activity, whole blood obtained at 0.083 (5 min), 2, 24, 48 and 72 h following eritoran administration was assessed for ex vivo activity by measuring the ability of 1 and 10 ng/ml LPS to elicit TNF-alpha release.Results. Total plasma cholesterol and triglyceride levels were significantly higher in cholesterol-fed rabbits compared to the rabbits fed a regular chow diet. Diet had no effect on the estimated plasma PK parameters. However, PD activity of both small and large micelle eritoran as measured by an ex vivo challenge dose of 1 ng/ml LPS was reduced in blood of cholesterol-fed rabbits compared to normal-fed rabbits. Comparison of PK parameters for small and large micelles indicated that small micelles had increased AUC(0-72 h), decreased plasma clearance and increased initial concentration (measured at 5 min post administration) compared to the large micelle formulation. Consistent with this observation, eritoran formulated into small micelles had significantly greater ex vivo activity than large micelles and was independent of TC and TG concentrations.Conclusions. These findings suggest that plasma pharmacokinetics and activity of eritoran maybe influenced by eritoran micelle size and plasma TC and TG concentrations.

BACKGROUND:Lipid A, the toxic moiety of endotoxin, is linked to multiple complications after cardiac surgery, including fever, vasodilation, and pulmonary and renal dysfunction. The lipid A antagonist eritoran (or E5564) prevents endotoxin-induced systemic inflammation in animals and humans. In this study we assessed the safety of eritoran administration in patients undergoing cardiac surgery and obtained preliminary efficacy data for the prophylaxis of endotoxin-mediated surgical complications.METHODS:A double-blind, randomized, ascending-dose, placebo-controlled study was conducted at nine hospitals. Patients undergoing coronary artery bypass graft and/or cardiac valvular surgery with cardiopulmonary bypass were enrolled. Patients received a 4-h infusion of placebo (n = 78) vs 2 mg (n = 24), 12 mg (n = 26), or 28 mg (n = 24) of eritoran initiated approximately 1 h before cardiopulmonary bypass.RESULTS:No significant safety concerns were identified with continuous safety monitoring, and enrollment continued to the highest prespecified dose (28 mg). No statistically significant differences were observed in most variables related to systemic inflammation or organ dysfunction/injury.CONCLUSIONS:This Phase II safety study suggests that the administration of the novel lipid A antagonist, eritoran, is not associated with overt toxicity in cardiac surgical patients. Blocking lipid A with eritoran does not appear to confer any clear benefit to elective cardiac surgical patients.

Toll-like receptor 4 (TLR4) controls the major responding signaling system that detects the presence of Gram-negative infectious pathogens, by responding to endotoxin from their outer membrane. Normally, TLR-bearing cells signal the immune system to mount a pro-inflammatory, antibacterial response and resolve infection. However, TLR4 can also respond to a variety of 'endogenous' ligands, such as fibronectin and heat shock proteins. Overstimulation or continued stimulation of TLR4 by any ligand can result in a systemic inflammatory response, progressing to hypotension, shock, organ failure and even death. This review discusses current, preclinical and clinical research regarding eritoran (E-5564), an analog of the non-toxic lipid A from Rhodobacter sphaeroides, as well as other antagonists of TLR4 in a variety of diseases.