Tamiflu effective against human H5N1 and avian H5N1 influenza virus

Main Category: Infectious Diseases / Bacteria / Viruses
Also Included In: Flu / Cold / SARS
Article Date: 02 Nov 2004 - 12:00 PDT

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Experts confirm major role for Tamiflu in pandemic management and call for stockpiling -

New data presented at the InterScience Conference on Antimicrobial Agents and Chemotherapy (ICAAC), Washington DC confirm that Tamiflu (oseltamivir), an oral neuraminidase inhibitor (NAI), is effective against human and avian H5N1 influenza virus.1 These data are particularly important as avian influenza strains, such as H5N1, are considered by experts to be the most likely source of a pandemic strain, against which older antivirals are not effective. This highly pathogenic strain is currently circulating in Vietnam and Thailand, and is responsible for the deaths of more than 30 people since January.2

"These data add to previous studies by the WHO and the Centre for Disease Control and Prevention (CDC) in the US, and suggest that Tamiflu can be expected to be effective against any mutating influenza virus - which is the key to a pandemic," commented Professor John Oxford, St Barts and The London, Queen Mary's School of Medicine and Dentistry, London, UK. "Since antivirals such as Tamiflu can be stockpiled, we are in a strong position to ensure that we are prepared for the next pandemic - however, few governments have adequate stock. I urge governments to follow WHO guidance and ensure that stockpiles of antivirals are assembled in good time," he concluded.

Roche has been working with many governments over the last few months to discuss their needs for stockpiling of Tamiflu and has recently taken steps to increase the manufacturing capacity, far beyond what is required for seasonal use and firm pandemic orders, resulting in doubling of production capacity of Tamiflu in 2004 with plans to double capacity again in 2005.

"We realise how important it is for governments to have stockpiles of Tamiflu in place when an influenza pandemic hits as the production lead time is so long. In order to meet the needs of governments, we have taken steps to increase our manufacturing capacity, at risk, even though we haven't had many firm orders", commented William M. Burns, Head of Roche's Pharmaceuticals Division.

Since the production of Tamiflu is complex, and takes approximately 12 months, it is important for governments to work with Roche to plan for their stockpiles. Once the pandemic hits, due to production timelines sufficient Tamiflu will not be available to meet last minute demands. To date only a few governments have announced firm orders.

About Tamiflu (oseltamivir)

Tamiflu is designed to be active against all clinically relevant influenza viruses.3 It works by blocking the action of the neuraminidase enzyme on the surface of the virus. When neuraminidase is inhibited, the virus is not able to spread to and infect other cells in the body.

Tamiflu delivers:

-- 38 percent reduction in the severity of symptoms3

-- 67 percent reduction in secondary complications such as bronchitis, pneumonia and sinusitis in otherwise healthy individuals4

-- 37 percent reduction in the duration of influenza illness5

-- Tamiflu was shown to provide up to 89 percent overall protective efficacy against clinical influenza in adults and adolescents who had been in close contact with influenza-infected patients5

In children, Tamiflu delivers:

-- 36 percent reduction in the severity and duration of influenza symptoms6

-- 44 percent reduced incidence of associated otitis media as compared to standard care7

Avian Influenza and Pandemics

Most avian influenza viruses are not infectious to humans, but, should an avian and a human influenza virus co-infect a human or a pig, the virus strains can join, mutate and create a completely new virus, which may be transmissible from animals to humans and from humans to humans. Such a strain would be entirely new in composition, so vaccines developed and administered to date to protect humans during seasonal epidemics, would be ineffective against this new strain, leaving the population vulnerable to infection. Experts believe the next influenza pandemic could result from such a mutation of virus strains.

World Health Organisation

The WHO has recommended as part of its Pandemic Preparedness Plan that countries establish stockpiles of antiviral treatments such as Tamiflu, which are effective against all strains of the influenza virus. The Pandemic Preparedness Plan, along with details of the 15 countries that have implemented national plans, can be viewed on the Internet.

About Roche

Headquartered in Basel, Switzerland, Roche is one of the world's leading research-intensive healthcare groups. Its core businesses are pharmaceuticals and diagnostics. As a supplier of innovative products and services for the prevention, diagnosis and treatment of disease, the Group contributes on a broad range of fronts to improving people's health and quality of life. Roche is number one in the global diagnostics market, the leading supplier of medicines for cancer and transplantation and a market leader in virology. In 2003, the Pharmaceuticals Division generated 19.8 billion Swiss francs in prescription drug sales, while the Diagnostics Division posted sales of 7.4 billion Swiss francs. Roche employs roughly 65,000 people in 150 countries and has R&D agreements and strategic alliances with numerous partners, including majority ownership interests in Genentech and Chugai.

All trademarks used or mentioned in this release are legally protected.

1 Antiviral Activity of Oseltamivir Carboxylate Against a Human Isolate of the current H5N1 chicken strain. Balasingam S et al. 44th ICAAC, Washington D.C., 30 Oct -2 Nov Poster#3839

2 http://www.who.int/csr/don/2004_10_04/en/

3 Treanor JJ et al. Efficacy and safety of the oral neuraminidase inhibitor oseltamivir in treating acute influenza: a randomized, controlled trial. JAMA 2000;283: 1016-24

4 Kaiser et al. Impact of Oseltamivir treatment on influenza-related lower respiratory tract complications and hospitalisations. Arch Intern Med. 163:1667-1672 (2003)

5 Welliver R. W. et al. Effectiveness of oseltamivir in preventing influenza in household contacts: a randomized controlled trial. JAMA, 2001 Feb 14; 285(6): 748-754

6 Whitely RJ, Hayden FG et al; Oral oseltamivir treatment of influenza in children, Pediatr Infect Dis J 2000; 20: 122-133

7 Roche data on file, 2003