Severe acute respiratory syndrome (SARS) is a newly recognized illness that has rapidly spread throughout Asia, North America and Europe. SARS has been found to be a highly infectious disease with high mortality, considerable occupational hazard, and no specific therapy. On July 5, the World Health Organization (WHO) finally declared that SARS has been contained around the world. However, it seems likely that SARS will return. Therefore, the development of effective drugs to treat SARS infection is imperative. Ridgeway Biosystems, Inc. is developing novel drugs for targeting cancer and infectious diseases using its proprietary 2-5A antisense technology. 2-5A antisense exploits a ubiquitous cellular ribonuclease L (RNase L), which is activated by binding to 2-5A. By linking 2-5A to antisense, RNase L is directed to a specific RNA molecule, in this case to SARS RNA. The efficiency of 2-5A antisense is many times superior to corresponding antisense lacking 2-5A and it avoids adverse non-specific effects associated with RNAi. We propose to develop an effective and marketable 2-5A antisense drug for the treatment of SARS infection. ? ? ?