6 CURRENT EFFICACY OF RECOMMENDED EMPIRICAL ANTIBIOTIC THERAPY IN PATIENTS WITH CIRRHOSIS AND BACTERIAL INFECTION

Parallel Session 1: HEPATITIS C VIRUS DRUG DEVELOPMENT I 5 IDENTIFICATION OF RECURRENT SOMATIC MUTATION ACTIVATING GP130 IN INFLAMMATORY HEPATOCELLULAR TUMORS: A NEW PATHWAY OF TUMORIGENESIS IN HUMAN/S J. Zucman-Rossi1 , S. Rebouissou1 , M. Amessou1 , G. Couchy1 , K. Poussin1 , C. Balabaud2,3 , P. Bioulac-Sage2,3 , G. Genthep4 . 1 Inserm U674, Paris, 2 CHU Bordeaux, 3 Inserm U889, Bordeaux, 4 Inserm, Paris, France E-mail: [email protected] Inflammatory hepatocellular adenomas (IHCA) are benign liver tumours defined by the presence of inflammatory infiltrates and by an overexpression of inflammatory proteins. IHCA are usually developed in women and their occurrence is frequently associated with obesity and alcohol intake. Recently, we identified somatic mutations activating gp130 in 60% of IHCA (Rebouissou et al, Nature, in press), thus defining gp130 as a new oncogene in human tumors. The aim of this work was to evaluate frequency of gp130 mutations in a wide series of tumors. Method: A series of 400 well-characterised hepatocellular tumors was screened including hepatocellular adenomas, carcinomas, hepatocholangio-carcinoma, fibrolamellar carcinomas and intra-hepatic cholangiocarcinomas. 100 tumors from different organs were also collected. To search for mutations, gp130 exons were screened in all samples and function of 7 different mutants was analysed in HEP3B. Results: We identified a somatic mutation in 65% of the IHCA including 24 different small in-frame deletions or duplications. Spectrum of mutations shows that mutations clearly target the IL-6 binding site in gp130. We further demonstrated that the expression of the most frequent gp130 mutants in HEP3B cells activates STAT3 in absence of IL-6. We searched for possible interaction and cooperation of gp130 activation with other pathways altered in hepatocellular adenoma. HNF1a inactivation and gp130 activation were mutually exclusive in HCA (P < 10−4 ). By contrast, in half of the b-catenin activating HCA, we identified a gp130-activating mutation. For two IHCA associated with a malignant transformation, both an activating gp130 and b-catenin mutations were found. Further, analysis of 220 hepatocellular carcinomas revealed rare gp130 alterations in all cases accompanied by b-catenin-activating mutations, suggesting a cooperative effect of these signalling pathways in the malignant transformation of hepatocytes. Conclusion: This is the first identification of gp130 somatic activating mutations in human tumors; this finding reinforces the role of inflammation in hepatocarcinogenesis and particularly in the malignant transformation of HCA. Moreover, gp130 mutations enable to refine the molecular classification of hepatocellular tumors in human. 6 CURRENT EFFICACY OF RECOMMENDED EMPIRICAL ANTIBIOTIC THERAPY IN PATIENTS WITH CIRRHOSIS AND BACTERIAL INFECTION J.G. Acevedo, J. Fernandez, M. Castro, O. Garcia, C. Rodriguez de Lope, M. Navasa, P. Gines, V. Arroyo. Hepatology, Hospital Clinic de Barcelona. IMDiM. IDIBAPS. Ciberehd. University of Barcelona, Barcelona, Spain E-mail: [email protected] Background and Aims: Recent changes in the epidemiology of bacterial infections in cirrhosis may have decreased the efficacy of third-generation cephalosporins and amoxicillin-clavulanic acid, the gold-standard empirical antibiotic treatments, in patients with cirrhosis and bacterial infection. Methods: This study consisted of a prospective evaluation of all bacterial infections diagnosed in patients with cirrhosis in our Liver Unit between September 2005 and September 2007. Results: A total of 224 patients presented 500 bacterial infections in 393 admissions. Spontaneous bacterial peritonitis (SBP, n = 126 cases), urinary infections (96) and cellulitis (66) were the most frequent proved infections. One hundred and sixty five infections were nosocomial (33%). Multiresistant bacteria were mainly isolated in nosocomial infections: SBP

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(28% vs. 3%; p:0.001), urinary infections (63% vs. 22%; p: 0.0001), cellulitis (36% vs. 6%; p:0.04) and pneumonia (29% vs. 11%, p= ns). Extended spectrum betalactamase producing enterobacteria (42 cases), Pseudomona aeruginosa (17 cases), meticillin-resistant Staphylococcus aureus (14 cases) and Enterococcus faecium (14 cases) were the main multiresistant bacteria isolated in the study. Resolution of infection with empirical antibiotic treatment was significantly higher in communityacquired than in nosocomial infections (83% vs. 44% in SBP, p:0.001; 78% vs. 34% in urinary infections, p:0.0001; 87% vs. 36% in cellulitis, p:0.003 and 53% vs. 17% in pneumonia, p = 0.05). Conclusions: Multiresistant bacteria frequently cause nosocomial infections in cirrhosis. Third-generation cephalosporins or amoxicillinclavulanic acid are ineffective in a high proportion of these infections. Empirical antibiotic treatment of nosocomial infections in cirrhosis should include antibiotics with a broader antibacterial spectrum such as carbapenems and glycopeptides.

Parallel Session 1: HEPATITIS C VIRUS DRUG DEVELOPMENT I

7 PRECLINICAL CHARACTERIZATION OF PRO 206, AN ORALLY ACTIVE SMALL-MOLECULE HEPATITIS C (HCV) ENTRY INHIBITOR D. Qian1 , G. Coburn1 , A.Q. Han1 , J.-M. de Muys1 , C. Gauss1 , K. Provoncha1 , M. Canfield1 , D. Paul1 , S. Mohamed1 , S. Moorji1 , D. Fisch1 , J. Murga1 , Y. Rotshteyn2 , P.J. Maddon3 , W.C. Olson1 . 1 Research and Development, 2 Preclinical Development, 3 CEO, Progenics Pharmaceuticals Inc., Tarrytown, NY, USA E-mail: [email protected] Background: Combinations of specific anti-viral drugs, with complementary mechanisms of action and determinants of resistance, offer the potential to improve sustained virologic response rates and to improve tolerability for HCV infected patients. To date, most drug discovery and development efforts have targeted two HCV enzymes: the NS3/4A serine protease and the NS5B RNA-dependent RNA polymerase. Targeting HCV entry represents a novel therapeutic approach that has been validated clinically for other pathogenic viruses. We have discovered a small-molecule inhibitor of HCV entry, PRO 206, and describe herein its preclinical characteristics. Methods: The activity of PRO 206 was evaluated in an HCV pseudoparticle (HCVpp) assay using fusogenic envelopes isolated from multiple HCV+ patients. Antiviral activity was also measured against authentic HCV in cell culture (HCVcc). Cytotoxicity was assessed in a standard CellTiter Glo assay. Selectivity was determined against a panel of pseudoviral particles that were typed with the envelope glycoproteins from unrelated viruses. PRO 206 was also profiled against a broad panel of human receptor and enzyme targets of pharmacologic interest. Pharmacokinetic properties were characterized in rats after intravenous or oral administration. ADME (absorption/distribution/metabolism/excretion) properties were assessed in a panel of in vitro assays including Caco2 permeability, human microsomal stability, and inhibition of cytochrome P450s. Results: PRO 206 demonstrated potent and selective inhibitory activity against HCVpp and HCVcc at concentrations that had no measurable effect on cell viability, entry of unrelated viruses, or a broad panel of human receptors and enzymes. PRO 206 also demonstrated favorable ADME properties, as well as high oral bioavailability and a prolonged pharmacokinetic half-life in animals. Conclusions: Preclinical data indicate that PRO 206 was a potent, selective, non-cytotoxic and orally bioavailable inhibitor of HCV entry. The antiviral and pharmacokinetic properties of PRO 206 suggest the potential for once-daily dosing in humans. Based on these data, PRO 206 has been