Tamiflu (Oseltamivir) Could be Effective in the Treatment and Prevention of Avian Influenza

Roche confirms that oral anti-influenza drug Tamiflu (oseltamivir) could be effective in the treatment and post-contact prevention of avian influenza that is circulating in the Far East.

Tamiflu has been tested in a pre-clinical setting against a wide range of influenza virus strains. Despite the lack of clinical data, these pre-clinical findings provide reassurance that Tamiflu can be expected to be active against any influenza virus neuraminidase enzyme subtype, including the H5N1 strain. This strain is associated with the recent outbreak of avian influenza in Asia.

The WHO in its interim recommendations for the protection of persons in contact with animals potentially infected with highly pathogenic avian influenza viruses, advises that ‘Oseltamivir be readily available for the treatment of suspected H5N1 respiratory infections in cullers and farm workers involved in the mass culling.

"Roche is committed to making Tamiflu available to fight this latest avian influenza outbreak. Based on the current WHO approach we have adequate supplies and we continue to work closely with the authorities in order to monitor the development and act accordingly," says William M. Burns, Head of Roche Pharmaceuticals Division.

In the UK, Roche carry sufficient stocks to meet demands of influenza outbreaks within the UK. In anticipation of an outbreak, Roche regularly discuss stock levels with national authorities in England, Northern Ireland and Scotland throughout the influenza season. In the event of a significant outbreak, a centralised process for stock replenishment is in place which can despatch capsules to affected countries in the EU within 4-5 days.

In the event of an epidemic, oseltamivir, the active ingredient of Tamiflu can be supplied to national authorities in bulk.

About Avian Influenza

According to the WHO avian influenza is an infectious disease of birds caused by type A strains of the influenza virus. Fifteen subtypes of influenza virus are known to infect birds, thus providing an extensive reservoir of influenza viruses potentially circulating in bird populations. To date, all outbreaks of the highly pathogenic form have been caused by influenza A viruses of subtypes H5 and H7.

For further information: World Health Organization

About Tamiflu

Tamiflu is the latest of the neuraminidase inhibitor (NI) class of medicines designed specifically to prevent the influenza virus from spreading and infecting other cells. It is effective against all common strains of influenza (types A and B). The medication targets one of two major surface structures on the influenza virus, the neuraminidase protein. The neuraminidase protein is virtually the same in all common strains of influenza. If neuraminidase is inhibited, the virus is not able to infect new cells.

In pre-clinical testing, Tamiflu demonstrated activity against the influenza virus responsible the 1997 Hong Kong outbreak, (also an ‘H5N1’ strain), at concentrations equivalent to those of the 75 mg twice daily dose approved for treating influenza in humans.

In adults, if taken within 36 hours of the onset of influenza, Tamiflu reduces the severity of symptoms by up to 40% and the duration of illness by 30%, as compared to standard care. 2 Tamiflu has been shown to significantly reduce the incidence of influenza-associated chest infections requiring antibiotic therapy by over 50% in adults.ii Treatment with Tamiflu also significantly reduce hospitalisations as compared to standard care.

Tamiflu is also effective in children, reducing the severity and duration of influenza symptoms. The incidence of associated otitis media is reduced by 44% with Tamiflu as compared to standard care.

In addition, Tamiflu prevented influenza developing in 89% of adults and adolescents who have been in close contact with influenza-infected patients.

The National Institute for Clinical Excellence (NICE) recommended the use of Tamiflu for the treatment of influenza in ‘at risk’ adults and children and, for preventing influenza in ‘at-risk’ individuals.

Tamiflu, which is available as capsules and in a suspension formulation for children was launched in the UK in January 2003. To date, Tamiflu has been used to treat around 10 million influenza sufferers in over 50 countries worldwide.

For more information on influenza, please visit. www.fluinfo.org.