REHOVOT, Israel ¿ XTL Biopharmaceuticals Ltd., which attracted more than $12 million in investments in 1998, is moving closer to a cure for viral disease with its proprietary Trimera mouse containing human tissue. This powerful development engine for high-affinity, fully human monoclonal antibodies demonstrates its high value as a small animal model of hepatitis B ¿ until now considered the stumbling block to creating effective therapy.
The XTL Trimera human disease/human tissue in a mouse ¿circumvents the staggering costs and small sample sizes of chimpanzees and other larger animals,¿ while ¿allowing us to screen a lineup of potential therapeutic agents awaiting preclinical evaluation,¿ said Daniel Shouval, head of the Liver Unit and chief physician at the Hadassah Medical Organization in Jerusalem. (Large sample size is essential for testing diseases like HBV and HCV, to account for shifts in viral load during disease progression.)
Martin Becker, president and CEO of XTL, said, ¿The hepatitis B and a similar model for hepatitis C, which is in the works, are the test vehicles for XTL¿s own antiviral therapeutic candidates.¿ Trimera¿s human immune system in mice is created by engrafting HBV in vitro-infected human liver tissue into mice irradiated to ablate their own immune systems and previously transplanted with bone marrow from an SCID or other immune-deficient mouse. These mice mimic the course of human disease, and cessation of anti-HBV treatment resulted in the rebound of viral loads. n