Bird flu vaccine shows good results in early trial

CHICAGO - Preliminary results from an early clinical trial of a vaccine for pandemic bird flu suggest the vaccine is safe and well tolerated and may prove effective against divergent strains of the disease, Baxter International Inc said today.

"This is the first clinical demonstration that a candidate H5N1 (bird flu virus) vaccine can induce antibodies that neutralize widely divergent strains of H5N1," said Noel Barrett, vice president of Global research and development for Baxter's vaccines business.

"These preliminary data, which must be confirmed in a larger study, suggest that the vaccine may provide wider protection for a larger number of people before and during a pandemic," he said.

H5N1 mainly affects birds, but experts fear it could mutate into a strain easily transmitted from person to person, capable of killing millions of people in a global pandemic.

An H5N1 virus has killed at least 148 people since 2003, mostly in Indonesia, Vietnam, Thailand and China, according to the World Health Organisation.

Baxter said the clinical trial of the experimental H5N1 pandemic vaccine in 270 healthy adults in Austria and Singapore suggested the vaccine had similar side effects to those reported for seasonal flu vaccines.

The preliminary results suggest the vaccine is highly capable of producing an immune response and can create antibodies to H5N1 even at the lowest dose level, it said.

A preliminary analysis of serum samples obtained from study subjects showed the vaccine was able to neutralise the pandemic virus contained in the vaccine as well as other diverse strains of the H5N1 virus.

Baxter plans to begin a late-stage clinical trial of the vaccine early next year and said it will present final results by the end of 2007.

Deerfield, Illinois-based Baxter has said its cell-based vaccine production system is more rapid than traditional methods using chicken eggs.

Baxter's H5N1 pandemic vaccine candidate was produced using four different antigen concentrations. Two of the concentrations were with and without adjuvant, a substance added to vaccines to improve immune response.

Baxter and a number of other companies are working to develop a vaccine to protect against a potential bird flu pandemic. GlaxoSmithKline Plc in July said its vaccine could be mass produced in 2007.

There is currently no vaccine against the virus, which is now treated with Tamiflu, also known as oseltamivir, an antiviral drug made by Roche and Gilead Sciences Inc.

Glaxo also makes the inhaled drug Relenza under license from Australia's Biota, which also appears to treat both types of flu.

- REUTERS