Inhalant shows no benefit against flu By Kathleen Fackelmann USA TODAY
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A federal advisory panel Wednesday recommended against Food and Drug Administration approval of an inhalant drug aimed at treating the flu, saying it has no proven benefit over a placebo drug.
The FDA usually follows its panels' recommendations, but GlaxoWellcome, maker of Relenza (zanarnivir), hopes the agency will approve the drug despite the panel's vote.
The company developed Relenza to curb the explosive outbreaks of flu that pose a serious public health threat. An estimated 55 million people in the USA suffer from the flu each year at an estimated cost of $5 billion.
Although often confused with the common cold, influenza is a much more serious illness, particularly for people age 65 and older or anyone with a weakened immune system.
By the end of a day of scientific presentations, 13 advisory panel members said the company had not shown that Relenza was effective; only four members said they thought the company had shown the drug lessened the severity of the flu.
GlaxoWellcome officials presented data from clinical trials suggesting that the drug alleviates symptoms faster than a placebo when taken within 48 hours of coming down with the flu. The company's data from international studies suggest that patients who take the drug recovered about two days earlier than those on the placebo.
But a study conducted in the USA and Canada, the largest and most powerful study to date, showed only a one-day benefit. Michael Elashoff, a statistical reviewer for the FDA, said even a one-day benefit may be overstating the case. He went back and examined the company's raw data from that study and said that, in most cases, people who were counted as "all better" in fact still had symptoms. He said he found no statistically significant difference in recovery time for people taking the drug as compared with the placebo.
Patients take Relenza using a small hand-held device similar to an asthma inhaler. The drug powder goes into the lungs, where the flu virus is replicating.
Relenza represents a new class of drugs called neuraminidase inhibitors. Neuraminidase is an enzyme that allows the flu virus to travel from one lung cell to another.
The drug blocks the enzyme and thus the spread of infection - at least in theory.
The FDA now will go back and consider the evidence on the drug. If it does decide to approve Relenza, a step that would be unusual given the panel's vote, GlaxoWellcome says it will have the drug on the market by the time the flu hits in the fall.
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