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Severe alcoholic hepatitis (sAH) is associated with a poor prognosis. There is no proven effective treatment for sAH, which is why early transplantation has been increasingly discussed. Hepatoblastoma-derived C3A cells express anti-inflammatory proteins and growth factors and were tested in an extracorporeal cellular therapy (ELAD) study to establish their effect on survival for subjects with sAH. Adults with sAH, bilirubin ≥8 mg/dL, Maddrey's discriminant function ≥ 32, and Model for End-Stage Liver Disease (MELD) score ≤ 35 were randomized to receive standard of care (SOC) only or 3-5 days of continuous ELAD treatment plus SOC. After a minimum follow-up of 91 days, overall survival (OS) was assessed by using a Kaplan-Meier survival analysis. A total of 203 subjects were enrolled (96 ELAD and 107 SOC) at 40 sites worldwide. Comparison of baseline characteristics showed no significant differences between groups and within subgroups. There was no significant difference in serious adverse events between the 2 groups. In an analysis of the intent-to-treat population, there was no difference in OS (51.0% versus 49.5%). The study failed its primary and secondary end point in a population with sAH and with a MELD ranging from 18 to 35 and no upper age limit. In the prespecified analysis of subjects with MELD < 28 (n = 120), ELAD was associated with a trend toward higher OS at 91 days (68.6% versus 53.6%; P = .08). Regression analysis identified high creatinine and international normalized ratio, but not bilirubin, as the MELD components predicting negative outcomes with ELAD. A new trial investigating a potential benefit of ELAD in younger subjects with sufficient renal function and less severe coagulopathy has been initiated. Liver Transplantation 24 380-393 2018 AASLD.

Previously, we reported the discovery of PSI-697 (1a), a C-2 benzyl substituted quinoline salicylic acid-based P-selectin inhibitor. It is active in a variety of animal models of cardiovascular disease. Compound 1a has also been shown to be well tolerated and safe in healthy volunteers at doses of up to 1200 mg in a phase 1 single ascending dose study. However, its oral bioavailability was low. Our goal was to identify a back up compound with equal potency, increased solubility, and increased exposure. We expanded our structure-activity studies in this series by branching at the alpha position of the C-2 benzyl side chain and through modification of substituents on the carboxylic A-ring of the quinoline. This resulted in discovery of PSI-421 with marked improvement in aqueous solubility and pharmacokinetic properties. This compound has shown oral efficacy in animal models of arterial and venous injury and was selected as a preclinical development compound for potential treatment of such diseases as atherosclerosis and deep vein thrombosis.

Selectins play a significant and well-documented role in inflammation and immune response. They initiate tethering and rolling of blood borne leukocytes leading to their activation, adhesion and subsequent extravazation into tissues. This is important for healthy immune response and tissue repair. However, dysregulation of selectins leads to exacerbation of disease. Atherosclerosis, restenosis, deep venous thrombosis and tumor metastasis are just a few of the diseases in which selectin blockade has been demonstrated to ameliorate disease pathology. Thus, selectins remain attractive targets for amelioration of disease.Summarized here are new patents/patent applications on selectin inhibition published since our last review in 2003 and any significant changes or progress made in demonstrating clinical safety and efficacy of therapeutics covered by patents/patent applications reviewed in 2003.A comprehensive review of new developments in the field of selectin inhibition through discussion of patents/patent applications from 2003 to August 2009, reports on clinical results where available and selected literature.The field of selectin inhibition has matured significantly in recent years in the ability to inhibit selectin/ligand interactions with drug-like molecules and to demonstrate disease modification in human trials.

SummaryP-selectin inhibition has been evaluated as a therapeutic for prevention and treatment of venous thrombosis. In this study, a novel oral small-molecule inhibitor of P-selectin, PSI-421, was evaluated in a baboon model of stasis induced deep vein thrombosis (DVT). Experimental groups included i) primates receiving a single oral dose of 1 mg/kg PSI-421 two days prior and continued six days after thrombosis (n=3); ii) primates receiving a single daily subcutaneous dose of 0.57 mg/kg enoxaparin sodium two days prior and continued six days post thrombosis (n=3); and iii) primates receiving no treatment (n=3).PSI-421 treated primates had greater percent vein reopening and less vein wall inflammation than the enoxaparin and controls at day 6. Microparticle tissue factor activity (MPTFA) was significantly lower in the animals receiving PSI-421 immediately after thrombosis (T+6 hours day 0) suggesting lower potential for thrombogenesis in these animals. PSI-421 also reduced soluble P-selectin levels versus controls at T+6 hours day 0, day 2 and 6. Experimental animals in any group showed no adverse effects on coagulation. This study is the first to demonstrate a reduction in MPTFA associated with vein reopening and reduced vein inflammation due to oral P-selectin inhibition in a baboon model of DVT.

P-selectin plays a significant and well documented role in vascular disease by mediating leukocyte and platelet rolling and adhesion. This study characterizes the in vitro activity, pharmacokinetic properties, and the anti-inflammatory and antithrombotic efficacy of the orally active P-selectin small-molecule antagonist PSI-697 [2-(4-chlorobenzyl)-3-hydroxy-7,8,9,10-tetrahydrobenzo[h] quinoline-4-carboxylic acid; molecular mass, 367.83]. Biacore and cell-based assays were used to demonstrate the ability of PSI-697 to dose dependently inhibit the binding of human P-selectin to human P-selectin glycoprotein ligand-1, inhibiting 50% of binding at 50 to 125 microM. The pharmacokinetics of PSI-697 in rats were characterized by low clearance, short half-life, low volume of distribution, and moderate apparent oral bioavailability. A surgical inflammation model, using exteriorized rat cremaster venules, demonstrated that PSI-697 (50 mg/kg p.o.) significantly reduced the number of rolling leukocytes by 39% (P < 0.05) versus vehicle control. In a rat venous thrombosis model, PSI-697 (100 mg/kg p.o.) reduced thrombus weight by 18% (P < 0.05) relative to vehicle, without prolonging bleeding time. Finally, in a rat carotid injury model, PSI-697 (30 or 15 mg/kg p.o.) administered 1 h before arterial injury and once daily thereafter for 13 days resulted in dose-dependent decreases in intima/media ratios of 40.2% (P = 0.025) and 25.7% (P = 0.002) compared with vehicle controls. These data demonstrate the activity of PSI-697 in vitro and after oral administration in animal models of both arterial and venous injury and support the clinical evaluation of this novel antagonist of P-selectin in atherothrombotic and venous thrombotic indications.

SummaryP-selectin inhibition has been shown to decrease thrombogenesis in multiple animal species. In this study, we show that a novel oral small-molecule inhibitor of P-selectin, PSI-697, promotes thrombus resolution and decreases inflammation in a baboon model of venous thrombosis. Experimental groups consisted of the following: 1) primates receiving a single oral dose of PSI-697 (30 mg/kg) daily starting three days pre-iliac vein balloon occlusion, and continued for six days; 2) primates receiving a single treatment dose of a low-molecular-weight-heparin (LMVVH) (1.5 mg/kg) daily starting one day pre-iliac balloon occlusion, and continued for six days; and 3) primates receiving a single oral dose of a vehicle control daily starting three days pre-iliac vein balloon occlusion, and continued for six days. Animals receiving PSI-697, although thrombosed after balloon deflation, demonstrated greater than 80% vein lumen opening over time, with no opening (0%) for vehicle control (p

Leukocyte recruitment of sites of inflammation and tissue injury involves leukocyte rolling along the endothelial wall, followed by firm adherence of the leukocyte, and finally transmigration of the leukocyte across cell junctions into the underlying tissue. The initial rolling step is mediated by the interaction of leukocyte glycoproteins containing active moieties such as sialyl Lewisx (sLex) with P-selectin expressed on endothelial cells. Consequently, inhibition of this interaction by means of a small molecule P-selectin antagonist is an attractive strategy for the treatment of inflammatory diseases such as arthritis. High-throughput screening of the Wyeth chemical library identified the quinoline salicylic acid class of compounds (1) as antagonists of P-selectin, with potency in in vitro and cell-based assays far superior to that of sLex. Through iterative medicinal chemistry, we identified analogues with improved P-selectin activity, decreased inhibition of dihydrooratate dehydrogenase, and acceptable CYP profiles. Lead compound 36 was efficacious in the rat AIA model of rheumatoid arthritis.

BackgroundVein wall injury after thrombosis is multifactorial but seems dependent on thrombus and local thrombotic and inflammatory mechanisms. We hypothesized that inhibition of vein wall injury through reduction of thrombotic and inflammatory events with P-selectin inhibition and/or low-molecular-weight heparin (LMWH) occurs independently of thrombus resolution in a rat model of venous thrombosis.MethodsMale rats underwent inferior vena cava (IVC) stenosis (94.4% ± 0.5% reduction in IVC diameter) to induce thrombosis. Rats were treated from 2 days after thrombosis until they were killed 7 days later. Groups consisted of (1) PSI-697, a P-selectin inhibitor (30 mg/kg; oral gavage daily); (2) LMWH-Lovenox (LOV; enoxaparin) 3 mg/kg subcutaneously daily; (3) PSI-697 (30 mg/kg; oral gavage daily) plus LOV 3 mg/kg subcutaneously daily (PSI + LOV); (4) and untreated controls. Evaluations included thrombus mass, vein wall tensiometry (stiffness [inverse of compliance]), intimal thickness scoring by light microscopy, vein wall inflammatory mediators by enzyme-linked immunosorbent assay, and vein wall inflammatory cells by histologic evaluation.ResultsThrombus mass was not reduced by any treatment. Animals treated with PSI-697 alone, LOV alone, or PSI + LOV demonstrated significant decreases in vein wall stiffness when compared with controls. The vein wall stiffness of the PSI-697–treated groups was also significantly lower than in the LOV-only group. Animals treated with PSI-697 showed a significantly decreased intimal thickness score when compared with vehicle control IVCs. Vein wall intimal thickening was also significantly decreased in animals treated with PSI-697 vs LOV. The PSI-697 and PSI + LOV groups manifested significant decreases in the immunoregulatory and inflammatory cytokine interleukin 13 as compared with controls and LOV. Vein wall monocyte chemotactic protein 1 levels were also significantly reduced in the PSI-697 and PSI + LOV groups vs control. Only PSI-697 significantly decreased vein wall levels of platelet-derived growth factor ββ. Both the LOV and PSI + LOV groups had significant increases in vein wall monocytes and total inflammatory cells vs controls.ConclusionsThese data suggest that both LMWH and PSI-697 inhibit vein wall injury independently of thrombus mass. P-selectin inhibition seemed superior to LMWH in measured parameters of injury and mediator inhibition.Clinical RelevanceDeep venous thrombosis (DVT) remains a serious health care problem in this country, affecting more than 250,000 patients annually. Chronic venous insufficiency, a major complication of DVT, promotes the impairment of venous outflow, loss of vein compliance, and valvular dysfunction. The current standard of care for both treatment and prophylaxis of DVT is low-molecular-weight heparin. However, this therapy confers a bleeding risk and does not protect against postthrombotic syndrome. In previous rat studies, using a recombinant P-selectin receptor antagonist (rPSGL-Ig) 2 days after thrombosis resulted in less vein wall fibrosis without a decrease in thrombus mass. Further studies in the rat model of DVT have shown that P-selectin inhibition also inhibits profibrotic cytokine production and vein wall collagen. This study evaluated the effects of P-selectin inhibition by using a novel oral agent (PSI-697) on the postthrombotic vein wall and compared this with the current standard of care.

P-selectin inhibition has been shown to decrease thrombogenesis in multiple animal species. In this study, we show that a novel oral small-molecule inhibitor of P-selectin, PSI-697, promotes thrombus resolution and decreases inflammation in a baboon model of venous thrombosis. Experimental groups consisted of the following: 1) primates receiving a single oral dose of PSI-697 (30 mg/kg) daily starting three days pre-iliac vein balloon occlusion, and continued for six days; 2) primates receiving a single treatment dose of a low-molecular-weight-heparin (LMWH) (1.5 mg/kg) daily starting one day pre-iliac balloon occlusion, and continued for six days; and 3) primates receiving a single oral dose of a vehicle control daily starting three days pre-iliac vein balloon occlusion, and continued for six days. Animals receiving PSI-697, although thrombosed after balloon deflation, demonstrated greater than 80% vein lumen opening over time, with no opening (0%) for vehicle control (p0.01). LMWH opening evident after balloon deflation slightly deteriorated over time compared to PSI-697. PSI-697 therapy also significantly decreased vein wall inflammation determined by magnetic resonance venography (MRV). Importantly, this beneficial opening occurred without measured anticoagulation. Animals receiving PSI-697 demonstrated significantly increased plasma D-dimer levels versus LMWH and control animals six hours post thrombus induction (p0.01). This study is the first to demonstrate the effectiveness of oral P-selectin inhibition to modify venous thrombogenesis, increase vein lumen opening, and decrease inflammation in a large animal model.

P-selectin-PSGL-1 interaction causes rolling of leukocytes on the endothelial cell surface, which subsequently leads to firm adherence and leukocyte transmigration through the vessel wall into the surrounding tissues. P-selectin is upregulated on the surface of both platelets and endothelium in a variety of atherosclerosis-associated conditions. Consequently, inhibition of this interaction by means of a small molecule P-selectin antagonist is an attractive strategy for the treatment of atherosclerosis. High-throughput screening and subsequent analoging had led to the identification of compound 1 as the lead candidate. Herein, we report the continuation of this work and the discovery of a second-generation series, the tetrahydrobenzoquinoline salicylic acids. These compounds have improved pharmacokinetic properties, and a number of them have shown oral efficacy in mouse and rat models of atherogenesis and vascular injury. The lead 31 (PSI-697), is currently in clinical development for the treatment of atherothrombotic vascular events.

BackgroundP-selectin inhibition with protein therapeutics such as antibodies or soluble ligands given intravenously can decrease thrombosis in a mouse ligation model of venous thrombosis. In this study, we hypothesized that oral inhibition of P selectin with a novel oral nonprotein inhibitor (PSI-697) would decrease thrombosis and circulating microparticle populations. This study evaluated the effects on thrombosis and circulating microparticle populations in this murine venous thrombosis model.MethodsMice underwent inferior vena cava ligation to induce thrombosis. Mice with high circulating level of P selectin, Delta Cytoplasmic Tail (^CT), mice gene-deleted for both E- and P-selectin knockout (EPKO), and wild-type C57BL/6 mice (WT) were studied without and with administration of PSI-697 in food (100 mg/kg daily) from 2 days before thrombosis until the end of the study. Animals were killed 2 and 6 days later. Evaluations included thrombus weight (TW), vein wall morphometrics, microparticle quantification by using fluorescence-activated cell sorter analysis, and vein wall enzyme-linked immunosorbent assays for interleukin (IL)-10, P selectin, and monocyte chemotactic protein 1.ResultsPSI-697 significantly decreased TW in WT and ^CT mice, with a treated vs nontreated TW of 132 ± 24 vs 228 ± 29 × 10−4 g (P = .014) and 166 ± 19 vs 281 ± 16 × 10−4 g (P = .001), respectively. At day 6, the effect was significant only in the ^CT group (P < .05). Drug therapy at day 2 significantly increased vein wall monocytes in WT mice and increased monocytes and total inflammatory cells in ^CT animals. A significant decrease in neutrophils and total inflammatory cells was seen in EPKO mice at day 2 with therapy. Therapy significantly increased platelet-derived microparticles and total microparticles in ^CT mice on day 2. Changes in treated WT and treated EPKO animals were not significant compared with respective vehicle treatments at day 2. On day 6, therapy significantly decreased total microparticles in EPKO animals. Vein wall expression of IL-10 increased in all groups with therapy at day 2 (n = 18) and was significantly increased in WT (2687.5 ± 903 pg/mL vs 636 ± 108 pg/mL total protein; P = .038) and ^CT (2078 ± 295 pg/mL vs 432 ± 62 pg/mL total protein; P = .001) mice. Therapy significantly decreased vein wall P selectin, monocyte chemotactic protein 1, and IL-10 levels at day 6.ConclusionsPSI-697 decreased thrombosis. P-selectin inhibition allowed vein wall inflammatory cell extravasation in this model of complete ligation. Circulating microparticles (platelet-derived microparticles and total microparticles) increased with P-selectin inhibition, possibly because of decreased consumption into the thrombus. In summary, the oral administration of an inhibitor to P selectin provides significant TW reduction.Clinical RelevanceDeep venous thrombosis is a significant national health problem in the general population. The average annual incidence of deep venous thrombosis is approximately 250,000 cases per year. The selectin family of adhesion molecules is thought to be largely responsible for the initial attachment and rolling of leukocytes on stimulated vascular endothelium. Recent studies have explored the possible therapeutic implications of P-selectin inhibition to modulate venous thrombosis. For example, prophylactic dosing of a recombinant P-selectin ligand decreases venous thrombosis in a dose-dependent fashion in both feline and nonhuman primate animal models. Additionally, treatment of 2-day iliac thrombi with a recombinant protein, P-selectin inhibitor, significantly improves vein reopening in nonhuman primates. It is interesting to note that P-selectin inhibition decreases thrombosis without adverse anticoagulation. On the basis of the results from these previous studies, the use of P-selectin antagonism is a logical therapeutic approach to treat venous thrombosis. All inhibitors developed to date are either proteins or small molecules with low oral bioavailability that require intravenous or subcutaneous injection. This study evaluates, for the first time, a novel orally bioavailable inhibitor of P-selectin (PSI-697).

Potential E- and P-selectin inhibitors were synthesized to explore a hydrophobic area on the E-selectin surface and the PSGL-1 protein binding site on the P-selectin surface that was recently defined by crystallography. Three series of mannose-based compounds (libraries A, B, and C) were synthesized using solution phase parallel synthesis. Biological evaluation of these compounds was done using two ELISA-based assays and transferred NOE (trNOE) experiments. Some of the compounds showed better activity than sLe(x) in the P-selectin assay.