XTL Biopharmaceuticals, Ltd. announced today the initiation of a Phase I study of XTL001, an investigational monoclonal antibody (MAb) product, to evaluate the safety profile and antiviral activity of the compound in chronically infected hepatitis B (HBV) patients. XTL001, a combination of two human MAbs, is the Company's lead compound and the first to be discovered and developed utilizing its proprietary Trimera(XTL) system, a breakthrough method for producing high- affinity, fully human monoclonal antibodies in mice. The clinical study is being conducted in the United States and Israel by researchers at the University of California San Francisco, Stanford University and the Hadassah University Hospital, Jerusalem. "There is a critically important need for new therapeutics to treat HBV infection. Currently, less than half of chronically infected patients have responded to the available treatments, and new mutants which are resistant to these drugs continue to emerge," stated Dr. Eithan Galun, from the Liver Unit at Hadassah University Hospital, Director of the Goldyne Savad Institute of Gene Therapy and a co-Principal Investigator of the study. "Based on preclinical studies in the proprietary Trimera(XTL) model system of human HBV, XTL001 looks to be a promising new therapeutic candidate for this serious disease. Studies have shown that it acts at multiple sites on the HBV surface antigen with a high degree of specificity, enabling it to effectively neutralize the virus. Additionally, XTL001 expresses a synergistic effect when used in combination therapy with other antiviral drugs, resulting in the reduction of viral loads for an extended duration." "This is the first of our drug candidates to enter clinical trials that was discovered, tested and validated utilizing our proprietary Trimera(XTL) technology," stated Martin Becker, Ph.D., President and Chief Executive Officer of XTL. "The initiation of this study validates our unique approach of generating novel MAb therapeutics as well as validating them in this versatile system. We are also excited to be working with these prestigious research institutions in two parts of the world to advance our study of XTL001 in the clinic. The results of preclinical studies have been very encouraging and we look forward to receiving initial data on the safety profile and antiviral activity from this human clinical study." XTL001 is a combination of two high-affinity, fully human MAbs that bind to distinct sites on the surface antigen of HBV to neutralize the virus and limit viral escape. This trial is a dose ranging study consisting of 15 chronically infected HBV patients. The patients are divided into five dose groups consisting of three patients each. The patients' viral load and general tolerance will be monitored at several intervals to determine the antiviral activity and safety of the drug. The Company expects that this will be followed by a Phase Ib dose escalation study. The Trimera(XTL) system is a breakthrough method which enables a normal mouse to carry functional human tissues and/or a human immune system. Trimera(XTL) can capitalize on a pre-existing clinically relevant immune response to enable the development of improved antibodies with enhanced specificity and potency for use as therapeutic drugs. Using the Trimera(XTL) system results in the rapid production of human monoclonal antibody-producing cells within a few weeks. In addition, using the Trimera(XTL) disease models can increase the probability of clinical success by optimizing the selection of targets/compounds early in the preclinical stages of development. This is particularly valuable for diseases like HBV and HCV where drug development has been seriously hampered by the absence of adequate small animal models. Other Principal Investigators of the study include Professor Emmet B. Keefe, M.D., Medical Director, Liver Transplant Program and Chief of Clinical Gastroenterology at Stanford University, Professor Daniel Shouval, M.D., Head of the Liver Unit and Chief Physician at the Hadassah University Hospital, and Norah Terrault, M.D., M.Ph., Assistant Adjunct Professor, Division of Gastroenterology at the University of San Francisco. XTL is a biopharmaceutical company developing fully human monoclonal antibody-based therapeutics with a primary focus on infectious diseases. The Company applies its proprietary drug discovery and development "engine," the Trimera(XTL) system, to produce high affinity, fully human antibodies to a broad range of disease targets including hepatitis B (HBV) and hepatitis C (HCV). In addition, XTL has unique, high-value animal models of human diseases including models for testing HBV and HCV therapeutic drugs. For more information about XTL, visit the Company's website at http://www.xtlbio.com. A backgrounder on utilizing the Trimera(XTL) System for monoclonal antibody production is available upon request. ots Original Text Service: XTL Biopharmaceuticals, Ltd. Internet: http://www.newsaktuell.de Contact: Martin Becker, Ph.D., President and CEO of XTL Biopharmaceuticals, Ltd., 972-8-940- 5134, becker@xtlbio.com, or Glenn Kazo, Vice President, Business Development and General Manager, XTL Biopharmaceuticals, Inc., 603-878-9857, gkazo@xtlbio.com, or Douglas MacDougall or Kari Lampka of Feinstein Kean Partners Inc., 617-577-8110 Web site: http://www.fkpi.com Web site: http://www.xtlbio.com