San Francisco, 28 September, 1999: The targeted delivery of Relenza results in high concentrations of the drug in the primary site of viral replication, the lungs, up to 24 hours after inhalation. It is also effective against A& B strain influenza, and reduces complications requiring antibiotics. These are the conclusions from three studies of Relenza (zanamivir), the new anti-flu treatment, being presented to physicians at a major anti-viral conference.
The data presented at the Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC), September 26-29, in San Francisco, USA, provide further evidence of the effectiveness of Relenza, and its highly targeted mode of administration, against both A & B strains of influenza.
Results from a laboratory study, presented at ICAAC1, showed that the inhalation of Relenza resulted in a high concentration of the drug in the lungs. These levels of the drug allow for continued anti-viral activity at the major site of viral replication and were retained up to 24 hours after a single 10mg inhaled dose. These data strongly support the use of an inhaled therapy that delivers its effect direct to the site of major viral replication.
A further benefit of the high concentrations achieved in the respiratory tract is that the possibility of development of resistance to the drug is reduced. Other influenza anti-virals have been of limited clinical use because the virus can often develop resistance to them rapidly.
The efficacy of the drug against influenza B was demonstrated by a meta-analysis of 220 patients, with confirmed B strain flu, from a total of 1,572 patients involved in five placebo-controlled studies. Using a regimen of 10mg twice daily (bid) for five days2, time to alleviation of symptoms (the primary endpoint) was reduced by 25 per cent to 4.5 days for those taking Relenza, down from 6.0 days for those on placebo.