XTL-001. XTL Pharmaceuticals.

XTL-001, a combination of two human high-affinity monoclonal antibodies with affinity to different regions of the HBV surface antigen (HBsAg), is under development by XTL Biopharmaceuticals as a potential passive immunotherapy for HBV infection. An IND for XTL-001 was submitted in the third quarter of 1998 and was approved by the FDA in March 1999. It has been anticipated that the use of two antibodies against different viral determinants would lower the probability of viral escape mutants. XTL-001 showed viral neutralization activity in the Trimera model for HBV infection and was several thousand-fold more active than current antibody-based therapies. XTL has anticipated that XTL-001 will be used as a combination therapy with existing drugs. In March 2002, Roberton Stephens predicted a 2006 launch for XTL-001, with sales expected to reach at least US$100 million.