Tamiflu Shown to Reduce Risk of Death in Patients with Influenza

Main Category: Flu / Cold / SARS
Article Date: 13 Sep 2005 - 3:00 PDT

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Results from two studies presented today at the European Scientific Working Group on Influenza (ESWI) congress in Malta, show that treatment with the oral 'flu drug Tamiflu (oseltamivir), significantly decreases the risk of death and influenza-related complications such as pneumonia.

Influenza affects up to one in 10 adults and one in three children annually .Complications include bronchitis, sinusitis, otitis media and pneumonia, which in serious cases can result in hospitalisation and even death. Children, the elderly and people with chronic respiratory or cardiovascular diseases are most at risk.

Today's data complement existing clinical trial evidence where Tamiflu has demonstrated a 67 percent reduction in secondary complications, by providing a "real-world" view of the benefits of Tamiflu use in everyday clinical practice.

The first study, using data from a large US health insurer, investigated the incidence of pneumonia, heart attacks (myocardial infarction) and death during the month following influenza diagnosis in patients who either received no medication (136,799) or who were prescribed Tamiflu (39,202). Tamiflu treatment was associated with a significantly reduced risk of pneumonia, death and possibly heart attacks, compared to untreated patients.1

"We know that Tamiflu leads to a significantly reduced incidence of influenza-related complications in a clinical trial setting," comments Dr Beth Nordstrom, epidemiologist, lead investigator of the mortality study described above. "The results of our new study are valuable as they reveal, in a large population of "real-world" influenza patients, that there is a lower risk of complications and death among Tamiflu users than among individuals who did not receive treatment."

The second study, using data from the Toronto Invasive Bacterial Disease Network, found that Tamiflu treatment in hospitalized influenza patients was associated with a significant clinical benefit and a reduced risk of death in patients treated within three days of symptom onset.2

"This data shows that Tamiflu has a very important effect in preventing mortality in patients with severe illness," comments Dr Alison McGeer, Infectious Disease Consultant, Mount Sinai Hospital Toronto, and coordinator of the study. "We hope to expand our findings into a controlled clinical trial to further examine this exciting effect."

Influenza-related complications generate additional costs for the healthcare system, both from an outpatient and inpatient perspective. Data from large hospital surveys conducted in the USA show that the rate of hospital admissions increases by 100 to 170 percent during influenza epidemics.4

About Tamiflu (oseltamivir)

Tamiflu is designed to be active against all clinically relevant influenza viruses. 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 symptoms5
-- 67 percent reduction in secondary complications such as bronchitis, pneumonia and sinusitis in otherwise healthy individuals3
-- 37 percent reduction in the duration of influenza illness
-- 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 patients
-- In children, Tamiflu delivers:
-- 36 percent reduction in the severity and duration of influenza symptoms
-- 44 percent reduced incidence of associated otitis media as compared to standard care
About the studies

The first study, reduction in influenza complications following oseltamivir use by Nordstrom et al. was a retrospective cohort study of influenza infected patients conducted using claims data from a large US health insurer.

-- The study involved patients with a diagnosis of influenza during one or more influenza seasons from 1999 to 2004 who received oseltamivir or no treatment
-- 39,202 influenza infected patients prescribed oseltamivir and 136,799 influenza patients without antiviral treatment were identified for the study
-- There was a significant (p < 0.001) reduction in risk for pneumonia and death (p = 0.02) in the oseltamivir treated group compared to the untreated group.
-- The risk of myocardial infarction was lower in the oseltamivir treated group however the effect failed to achieve statistical significance (p = 0.06).
-- Oseltamivir use was associated with a reduction in the risk of pneumonia and death

The second study, clinical features of laboratory confirmed influenza illness (LCII) requiring hospital admission in Ontario, Canada: implications for treatment recommendation by McGeer et al. was a population-based study of laboratory confirmed influenza illness requiring hospital admission on December 1, 2004 to April 30, 2005 .

-- Patients requiring hospital admission who had a positive direct test and/or culture for influenza A or B were enrolled into the study.

-- 237 patients with LCII requiring hospitalization were identified and clinical data are available for 172 patients. Institutionally acquired disease (IAD) occurred in 37 (22%) of cases.

-- Overall, 34/135 community-acquired cases (CAI), (1 child, 33 adults) were treated with oseltamivir, treatment was started a median of 4 days (range 1-8) after symptom onset.

-- Adults aged>65 with CAI who were treated with oseltamivir were less likely to die ( p=0.08) and to require ICU admission ( p=0.05).

-- The odds ratio for death for those treated with oseltamivir within 3d of symptom onset was 0.14, p=0.02.

-- Oseltamivir treatment of patients with influenza requiring hospitalization appears to be associated with significant clinical benefit.

Pandemic Stockpiling

The World Health Organization (WHO) advises that stockpiling antivirals in advance is presently the only way to ensure that sufficient supplies are available in the event of a pandemic. Roche has been working with many governments over the last few months to discuss their needs for stockpiling of Tamiflu and has received and fulfilled orders from around 30 countries. The magnitude of these orders varies from country to country: for instance, France, Finland, Iceland, Ireland, Luxembourg, Netherlands, New Zealand, Norway, Switzerland, and the UK are stockpiling or intending to stockpile adequate Tamiflu supplies to cover 20-40% of their population. In order to meet the government needs, Roche has taken steps to increase manufacturing capacity, doubling manufacturing capacity both in 2004 and again in 2005, with a further increase planned in 2006. In addition, manufacturing facilities producing Tamiflu have increased from one to three, with a fourth facility available later in 2005.

About Roche

Headquartered in Basel, Switzerland, Roche is one of the world's leading research-focused healthcare groups in the fields of pharmaceuticals and diagnostics. As a supplier of innovative products and services for the early detection, 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 a world leader in diagnostics, the leading supplier of medicines for cancer and transplantation and a market leader in virology. In 2004 sales by the Pharmaceuticals Division totalled 21.7 billion Swiss francs, while the Diagnostics Division posted sales of 7.8 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

References
1 Nordstrom B, et al. Reduction of influenza complications following oseltamivir use. Presented 13 September, 2005 at the European Scientific Working Group on Influenza (ESWI) congress, Malta. Abstract number S18-2
2 McGeer A, et al. Clinical features of laboratory confirmed influenza illness requiring hospital admission in Ontario, Canada: Implications for treatment recommendations. Presented 11September, 2005 at the European Scientific Working Group on Influenza (ESWI) congress, Malta.
3 Nguyen-Van-Tam JS. Epidemiology of influenza. In: Textbook of Influenza (Nicholson KG, Webster RG, Hay AJ, eds.). Oxford: Blackwell Science Ltd, 1998: 181-206
4 Kaiser at al. Impact of oseltamivir treatment on influenza-related respiratory tract complications and hospitalisations. Arch Intern Med. 163: 1667-1672 (2003)
5 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
6 Nicholson KG et al. Efficacy and safety of oseltamivir in treatment of acute influenza: a randomised controlled trial. Lancet 2000; 355:1845-1850
7 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
8 Whitely RJ, Hayden FG et al; Oral oseltamivir treatment of influenza in children, Pediatr Infect Dis J 2000; 20: 122-133
9 Roche data on file, 2003

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