XTL Biopharmaceuticals Presents Data Regarding its Hepatitis C Virus Small Molecule Program at Hep Dart 2007 - an International Scientific Conference on Viral...( VALLEY COTTAGE N.Y. Dec. 10 /- XT...),Health

VALLEY COTTAGE, N.Y., Dec. 10 /PRNewswire-FirstCall/ -- XTL Biopharmaceuticals Ltd. (Nasdaq: XTLB, TASE: XTL) announced today that it will make two scientific presentations related to its pre-clinical Hepatitis C virus (HCV) small molecule program at HEP DART 2007, an international scientific conference on viral hepatitis being held this week in Lahaina, Hawaii.

A poster presentation entitled "Mechanistic Characterization of Potent Small Molecule HCV Inhibitors that Target NS5A" describes a family of small molecule inhibitors of HCV that target the NS5A viral protein. Potency of these compounds was evaluated in a replicon assay, which is known to have good correlation with clinical efficacy and is the current gold standard for pre- clinical testing of inhibitors of HCV. In the replicon assay, the compounds had single-digit nM (nanomolar) and low double-digit nM potencies against genotypes 1b and 1a, respectively. These genotypes constitute the majority of HCV infections in the U.S.

New data presented further substantiate NS5A as the target of these compounds. The new data includes results from in vitro binding to NS5A, resistance selection, molecular genetic and molecular modeling studies.

NS5A is a viral protein that is essential for RNA production and is distinct from the protease and polymerase - the viral targets of the more advanced HCV inhibitors in clinical development. As such, inhibitors of NS5A are considered promising candidates for the treatment of HCV. As a relatively new target, only one NS5A inhibitor has entered clinical trials to date - A831 - which is presently in a Phase 1 clinical trial. A831 was developed by Arrow Therapeutics, which was recently acquired by AstraZeneca. The Company's compounds pr
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