By Lisa Seachrist
The antiviral flu therapy Relenza, developed by Biota Holdings Ltd. and marketed worldwide by Glaxo Wellcome plc, gained marketing approval in the 15 member countries of the European Union.
The approval, coming on the heels of an Australian approval in April, breathes new life into a product that some said was doomed following a negative FDA panel recommendation in February.
"What I think we are seeing now is that the promise of biotech is finally coming through," said Howard Zar, a U.S. spokesman for Melbourne, Australia-based Biota. "This is a drug that meets a very important need for a very large market. The market in the EU is similar in size to the U.S. market."
Zar also noted that despite difficulties in convincing the Antiviral Drugs Advisory Committee to endorse Relenza, the FDA notified the companies in April that it had extended the review period for the drug by three months to resolve clinical issues that arose during the panel hearing.
"Glaxo Wellcome is leading the filing in the United States and is working very closely with the FDA," Zar said. "Should the FDA approve Relenza, the European marketing experience could be very useful in educating physicians about the drug."
Relenza (zanamivir) was developed by Biota and is the first in a class of new drugs called neuraminidase inhibitors. It is a rationally designed drug that inhibits the neuraminidase enzyme on the surface of all varieties of the influenza virus. Neuraminidase facilitates the virus' ability to spread from cell to cell in the respiratory tract.
Relenza, an inhaled therapeutic, is designed to stop the function of neuraminidase and limit the course of an influenza infection, which typically lasts seven to 10 days. Taken early enough after infection, the drug eliminates symptoms 1.5 to 2.0 days sooner than taking no drug at all. Unlike the approved therapies rimantadine and amantadine, which are effective for only influenza type A, Relenza is effective against both the A and B strains of influenza.
While Glaxo Wellcome presented three clinical studies - two positive and one equivocal - to the advisory panel in February, the panel placed a great deal of weight on the equivocal North American study and chose not to recommend the drug for approval by a 13-4 vote. The drug continues to be studied in specific vulnerable groups, including children, people with chronic respiratory disease and the elderly.
In addition to Relenza, Gilead Sciences, Inc., of Foster City, Calif., has developed a neuraminidase inhibitor that marketing partner Hoffmann-LaRoche Inc., of Nutley, N.J., submitted to the FDA for review in May. It is in pill form.