The experimental flu drug zanamivir is taken twice a day through an inhaler

February 24, 1999
Web posted at: 6:05 p.m. EST (2305 GMT)

GAITHERSBURG, Maryland (CNN) -- By a vote of 13 to 4, a Food and Drug Administration advisory committee Wednesday recommended against approval of an experimental drug to treat the flu.

Members of the Anti-Viral Drugs Advisory Committee said they were not concerned about the safety of the drug, but were concerned the drug was not effective enough.

The largest study on zanamivir was done in the United States. Results showed that people who took the drug felt better in five days, compared to six days for people who took the placebo.

European and Australian studies showed the drug brought relief one and a half to two and a half days earlier than the placebo drug. The drug appeared to help alleviate symptoms such as fever, cough, muscle aches and fatigue.

"For effectiveness, (zanamivir) was a base hit, not a home run," said committee member Dr. Gregory Poland, a physician with the Mayo Clinic in Rochester, Minnesota.

Dr. Jacob Lalezari, who directed clinical trials of zanamivir in San Francisco, said the drug works by keeping the flu virus from reproducing. He said it blocks neuraminidase, a chemical used in the reproduction cycle of influenza.

He says zanamivir is an improvement over current flu medicines because it works against both major strains of the flu -- influenza A and influenza B.

The drug, manufactured by pharmaceutical company Glaxo-Wellcome, has no side effects, according to Lalezari.

The FDA can, if it wants, approve the drug against the advice of the advisory committee, but that usually does not happen.