bloomberg.com
Human Bird-Flu Fatalities Spur Need for More Effective Drugs
By John Lauerman
Feb. 5 (Bloomberg) -- Doctors and health officials are preparing to experiment with new drugs in an effort to find better ways to treat lethal bird flu infections.
The World Health Organization wants permission to use BioCryst Pharmaceuticals Inc.'s experimental peramivir antiviral to treat patients infected with the H5N1 avian influenza virus and other severe flu infections, said Frederick Hayden, a WHO medical officer. Injections of peramivir reach higher levels in patients' systems than oral drugs such as Roche Holding AG's Tamiflu, now the preferred drug for bird flu treatment, he said.
About 60 percent of the people infected with avian flu in Asia, Africa and the Middle East have died. Stronger treatments are needed, especially if the bird virus mutates into a form that spreads easily in people, Hayden said.
``The hope would be that in patients who present with particularly advanced respiratory symptoms, a more potent antiviral might be able to save more lives,'' Hayden said Feb. 2 in an interview at a conference in Washington.
BioCryst is also seeking regulatory approval to perform clinical trials in Asian countries to treat avian flu and severe flu cases, said James Alexander, the company's senior vice president of clinical and regulatory operations.
``If Dr. Hayden is going to take that proposal to the steering committee at WHO and move forward, we're very much behind that,'' he said yesterday in a telephone interview.
Glaxo's Relenza
Flu invades cells and hijacks their genetic material to make more viruses, which go on to infect more cells. Tamiflu, the drug made by Basel-based Roche that governments and the WHO have stockpiled to fight a possible pandemic outbreak, London- based GlaxoSmithKline Plc's inhaled Relenza antiviral and peramivir all target neuraminidase, a protein that enables newly created viruses to exit cells.
Doctors in Asia are preparing to test various doses of Tamiflu in patients with H5N1 and severe seasonal flu. Permission to use experimental doses of peramivir will be needed in countries, such as Indonesia, where the treatments could be used, Hayden said.
Peramivir injections can reach levels in the bloodstream that are 100 times higher than those hit by Tamiflu, Hayden said. Birmingham, Alabama-based BioCryst's drug has been shown to fight H5N1 in the test tube and animals, and the company received $103 million from the U.S. Department of Health and Human Services for development last month.
Resistant Strains
Alternatives to Tamiflu may also be needed if more strains of the virus turn out to be resistant to the Roche drug, Hayden said. Scientists in Egypt, Italy and the U.K. are examining a strain that killed two people after they were treated with the drug. When scientists analyzed the virus in a laboratory, it showed a genetic change that made it less sensitive to Tamiflu, otherwise known as oseltamivir.
While rare, genetic mutations that give H5N1 resistance to Tamiflu or make it less sensitive to the drug's antiviral properties have been found in birds, Hayden said.
``If there were widespread presence of a variant with reduced susceptibility to oseltamivir, one would need to consider additional management options in people who might have been exposed,'' he said.
Some Tamiflu-resistant strains have been shown to be susceptible to treatment with Glaxo's Relenza, Hayden said.
Other experimental drugs that doctors might use to treat H5N1 include Daiichi Sankyo Co.'s CS8958, a topical drug, Toyama Chemical Co.'s oral T-705, and Nexbio Inc.'s DAS181, another topical treatment.
WHO Meeting
The international health agency is planning a number of efforts to improve treatment for avian flu patients, Hayden said. The group will sponsor a March meeting in Turkey -- which has had 12 cases of the disease, including four deaths -- focused on improving treatment.
Doctors from all 11 countries where cases have been confirmed will attend, Hayden said. That includes Indonesia, which has had 63 deaths, the most in the world, Azerbaijan, Cambodia, China, Djibouti, Egypt, Iraq, Nigeria, Thailand, and Vietnam.
The health organization is also working to expand the range of patient information on its database of H5N1 cases, Hayden said. WHO would like to collect more data on the symptoms patients have when they arrive at hospitals and doctors' offices, what treatments are given, and how patients fare afterwards, he said.
To contact the reporter on this story: John Lauerman in Boston at jlauerman@bloomberg.net .
Last Updated: February 4, 2007 20:22 EST |
