An injectable flu drug is badly needed because many sick people can't swallow pills and severe illness can slow the body's ability to absorb oral medications, researcher Shigeru Kohno, MD, PhD, of Nagasaki University School of Medicine in Japan, tells WebMD.
In the 2008-2009 flu season, Kohno and colleagues randomly assigned 1,099 patients in Japan, South Korea, and Thailand to get either one to two doses of intravenous peramivir or five days of Tamiflu pills twice a day.
The study was conducted before the outbreak of the H1N1 swine flu.
Flu symptoms cleared up in an average of 82 hours in people given Tamiflu, compared with 81 and 78 hours for those given the higher and lower doses of peramivir, respectively.
Both drugs were safe, although people taking peramivir were less likely to experience nausea and diarrhea. The findings were presented at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.
Peramivir Awaiting FDA Approval
Peramivir, like Tamiflu and another flu drug, Relenza, blocks the flu enzyme neuraminidase, which is needed for the virus to spread throughout the body.
It has been designated for "fast track" approval by the FDA, according to its developer, BioCryst Pharmaceuticals of Birmingham, Ala.
Fred Hayden, MD, of the University of Virginia in Charlottesville, says he is "very enthusiastic" about the development of an IV treatment for
hospitalized patients as it makes rapid administration possible.
But he says he would like to see further study comparing the drug to a placebo, as peramivir was compared to Tamiflu in a flu season when many cases were somewhat resistant to Tamiflu.
Michael Ison, MD, an infectious diseases expert at Northwestern University in Chicago, who moderated the session at which the findings were presented, says many patients find a single IV treatment more convenient than swallowing pills for days.
"That gives peramivir an important advantage," he tells WebMD.
Other research on the seasonal flu
• In a study of 238 intensive care patients monitored during three recent flu seasons, patients were nearly three times more likely to survive if treated with Tamiflu than if they didn't get treatment.
• Tamiflu helped even though many patients didn't receive it until days after their symptoms started, says Allison McGeer, MD, of Mount Sinai Hospital in Toronto.
• In a study of 760 people with confirmed flu at two hospitals in Hong Kong, only four percent started on Tamiflu within two days of symptoms died in the hospital vs. six percent of those not given an antiviral drug.
• A registry of 215 human cases of bird flu worldwide shows that nearly 90 percent of patients who did not receive Tamiflu or other antiviral medicines died, compared with only half of those given Tamiflu treatment.
Flu Polypill Looks Promising
Other research shows that a flu polypill appears to work against many different flu viruses, even those that have developed resistance to one of the drugs in the combo.
The drug cocktail contains three drugs -- amantadine, ribavirin and Tamiflu -- that are already on the market. Alone, each has lost some of its punch against the flu because of the ability of the virus to mutate. The new research, so far conducted only in test tubes and animals, suggests the combination may be able to overcome the problem, says Amy Patick, PhD, of Adamas Pharmaceuticals, which funded the work.
The company is now enrolling patients in tests of the triple-drug combo, Patick says, and hopes to have results as early as next year.
By Charlene Laino
Reviewed by Louise Chang
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