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A 13-member scientific team from Hong Kong University has identified a three-drug cocktail that quadrupled the survival rate of mice with H5N1 avian flu. The cocktail combines an antiviral drug with two drugs that suppress the deadly inflammatory immune response to the virus.

In the mice tests, the cocktail produced a survival rate of 53.3% and a survival time of 13.3 days. That was a four-fold improvement on using the antiviral by itself (13.3%, 8.4 days), or no treatment (0%, 6.6 days). Treatment was started on the mice 48 hours after they were infected, even though current treatments have not shown any efficacy unless they are started within 48 hours.

The cytokine storm released by H5N1 closes up patients’ lungs, the mechanism that most often proves fatal in avian flu. Although the antiviral reduces the viral load, it does not address the more deadly immune response. Steroids, the usual treatment for inflammation, are unacceptable in cases of avian flu, because they suppress the entire immune response.

The cocktail identified by the Hong Kong scientists contains the popular antiviral drug Relenza, a GlaxoSmithKline (NYSE: GSK) treatment for flu, combined with two anti-inflammatories: the Pfizer (NYSE: PFE) non-steroidal anti-inflammatory COX-2 Celebrex and mesalazine, a drug available under several labels that is usually prescribed for Crohn’s disease of ulcerative colitis. Celebrex is the only major COX-2 NSAID available in the US after most drugs in the class were found to have significant cardiovascular side effects. Merck’s (NYSE: MRK) Vioxx was the most notable of the drugs withdrawn in the COX-2 aftermath.

The study, which was led by Zheng Bojian, Associate Professor of Microbiology at Hong Kong University, is published in the current issue of the Proceedings of the National Academy of Sciences.

Next, the Hong Kong researchers want to have the cocktail tested on humans, but Hong Kong does not currently have any cases of bird flu.

The H5N1 strain of bird flu first jumped the species barrier to humans in 1997 in Hong Kong, infecting 18 people, of whom six died. Since 2003, it has infected 383 people and killed 241, most of them in Asia.