ADVENTRX Pharmaceuticals, Inc. (Amex: ANX), a biopharmaceutical research and development company focused on commercializing proprietary product candidates for the treatment of cancer and infectious diseases, announced today that it presented results demonstrating synergistic activity against human and avian influenza (bird flu) viruses when the Company's broad-spectrum antiviral drug candidate, ANX-201 (thiophosphonoformic acid), was combined with oseltamivir phosphate (Tamiflu(R)) in preclinical tests. ANX-201 also demonstrated single agent antiviral activity against these viruses. The results were presented at the International Conference on Antiviral Research (ICAR) in Palm Springs, CA on Wednesday, May 2nd. "These results suggest we can simultaneously improve efficacy and lower dosages with a two drug regimen of ANX-201 and Tamiflu," said Evan M. Levine, chief executive officer of ADVENTRX. "We intend to continue to investigate the use of ANX-201 in avian flu." As a single agent, ANX-201 showed dose-dependent antiviral activity against human, equine and avian influenza virus. Fixed-dose combinations of ANX-201 and the neuraminidase inhibitor Tamiflu produced a supra-additive, or synergistic, antiviral activity against the human and avian influenza viruses, as demonstrated by an overall lowering of the drug concentrations required to achieve virus inhibition. ANX-201 dosage could be reduced up to 10 fold against human influenza strains H3N2 and H1N1, and up to 100 fold against avian influenza strain H5N2 when administered in combination with Tamiflu. Tests were performed in vitro using standard cell-based influenza infectivity assays. A copy of the poster presentation is available for download from the "Resources" section of the Company's web site at