RESEARCH TRIANGLE PARK, N.C. -- The first in a new generation of prescription influenza medications -- a class called neuraminidase inhibitors -- will hit supermarket pharmacies following U.S. Food and Drug Administration approval last month. Competition for the new drug may not be far behind.
Relenza, produced by Glaxo Wellcome Inc., based here, is an inhaled form of the anti-flu agent zanamivir. It was given the go-ahead July 26 despite a 13 to 4 vote against it by the FDA's own advisory panel. The panel requested more studies of the drug, especially of its effects on seniors and its use in the nursing-home environment. An FDA official said the agency made the rare approval against the committee recommendation due to a limited arsenal of flu medications.
"I can see where their concern would be in a nursing-home situation," said John Rupert, pharmacy supervisor for A&P's Farmer Jack division in Detroit. "You get a fast-mutating flu that becomes resistant -- then what do you treat the patients with?" He was not aware of the advisory panel's vote. "I would have to look seriously into that, I didn't know that was [declined]."
In an FDA press statement, the agency acknowledged possible risks associated with the drug. "Safety and effectiveness have not been established for the drug's use in preventing influenza," it said. "Bronchospasm was documented in some patients with mild or moderate asthma." A Glaxo official could not be reached for comment on the advisory panel's vote.
Scheduled to hit the market Oct. 1, Relenza is for treating patients over the age of 12 who have shown symptoms for no more than two days, said Glaxo. The kit, priced at $37 for wholesalers, includes a circular inhalation device called a Diskhaler. Patients inhale 10-mg of Relenza twice a day for five days. Said James Palmer, M.D., senior vice president at Glaxo, "We are very pleased that Relenza will be available for the 1999/2000 flu season."
The enzyme neuraminidase allows influenza to spread to healthy cells by breaking the bond between the virus and infected cells.
If approved, a drug called Tamiflu from Hoffman-La Roche, Nutley, N.J., would be the second neuraminidase inhibitor. Roche expects to hear from the FDA in October regarding the agency's decision on the new drug application. Roche's development partner, Gilead Sciences Inc., Foster City, Calif., expects Tamiflu to be ready for the upcoming flu season, according to John Martin, Gilead chief executive officer. Mentioning that Tamiflu would go head-to-head with Rilenza, Martin said, "It's a new market, so it remains to be seen actually how big it will be." The Roche drug is a pill containing the anti-viral agent oseltamivir phosphate and is intended for use by patients ages 18 to 65 who are otherwise healthy.
In the prescription market, "They're in a class by themselves," said Farmer Jack's Rupert. "I think it could be a valuable tool in stopping an epidemic in a regional area." But "are doctors going to be willing to prescribe this relatively quickly? Because it's going to be needed to be taken at the first onset of symptoms." He added that the inhaler "is going to be a problem as far as geriatric [patients] using it."