( NEW YORK--(BUSINESS WIRE)--May 15 2007...)SIGA Passes First Hurdle with Lassa Fever Antiviral ST-193,Health

This study was conducted under Biosafety Level 4 conditions at the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID) by Dr. Kathleen Cashman under the supervision of Dr. Mary Guttieri, who has been working on various hemorrhagic fever viruses at USAMRIID for over 12 years. Strain 13 guinea pigs were challenged with a lethal dose of Lassa virus and treated with ST-193 once a day for 14 days. Administration with ST-193 resulted in significant reduction in mortality at the two doses tested, 80 mg/kg and 25 mg/kg (71% of the animals survived at the low dose), whereas all of the control animals and those treated with ribavirin succumbed to the disease within 20 days of the challenge. The disease course in these guinea pigs recapitulates what is seen in human Lassa fever infections, and SIGA expects that this model is one of the two animal models that will be required to fulfill the U.S. Food and Drug Administration's "Animal Efficacy Rule."

"This is a tremendous milestone for our research group," said Dr. Dennis E. Hruby, SIGA's Chief Scientific Officer. "This study should provide the basis for advancing this lead candidate into IND-enabling activities in the near future."

Lassa virus, considered a hemorrhagic fever virus due to some of its prominent symptoms, is one type of arenavirus. Arenaviruses are potential biological weapons agents due to their ease of dissemination, person-to-person transmissibility, and potential to cause widespread illness and death. Creating and deploying antiviral drugs targeting arenaviruses will enhance national and global security by acting as a significant deterrent and defense against the use of arenaviruses as bioterror weapons. Six separate arenav
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