Company says bird flu vaccine working

Baxter International Inc. on Thursday said its bird flu vaccine is working for humans against several strains of the virus at low dosages, setting the stage for a final round of testing the company expects to complete by the end of this year.

The progress in testing Baxter's cell-based vaccine against strains of the H5N1 virus could help the Deerfield, Ill.-based medical products giant as it negotiates with countries around the world trying to protect their citizens from a possible bird flu pandemic. It has a few contracts, but some countries have been asking for more evidence the product works before signing any deals.

What's more, the continued progress of testing should provide consumers with more confidence, considering there is no commercially available bird flu vaccine. Bird flu vaccines being developed by Baxter and other companies and stockpiled have not been government-approved.

Baxter is among about a half-dozen vaccine makers in various stages of testing their products against the H5N1 strain of avian influenza that has killed 170 people, mostly in Asia. Baxter said its product is the first cell-based vaccine in clinical trials.

Baxter is leading the development of cell-based technology, which allows the company to make vaccines more quickly in larger quantities. For decades, technicians have injected strains of virus into millions of chicken eggshells by hand in a laborious, monthslong process.

"A good safety profile and cross immunity against multiple viral strains is critically important for governments considering the concept of using a vaccine before, or immediately after, a pandemic breaks out," said Dr. Hartmut Ehrlich, vice president of global research and development for Baxter's Bioscience business.

Baxter's trials have shown the vaccine to work in 76 percent of those tested.

The company also said its vaccine was tested without using so-called "adjuvant," an additive being used by some other companies that is believed to cause side effects. The findings unveiled Thursday come from study of 270 patients from Europe and Asia. Strains of the virus were taken from patients in Vietnam.

"What's important about Phase I/II data is that the results show that Baxter's vaccine works against many strains of the H5N1 avian flu virus without any additives (adjuvant) to boost effectiveness," said Baxter spokesman Chris Bona.

"Additives can add additional cost, and they are believed to cause side effects" such as headache and fever, he added.

At least one other company known to disclose results of its testing is British drug giant GlaxoSmithKline PLC, which said last year that an adjuvant helped its vaccine work against bird flu strains.

But Baxter said in a statement that side effects observed in the trial were "injection site reactions, headaches and fatigue." The company said there were "minimal" occurrences of such side effects, which were "similar to those reported for licensed egg-based, seasonal influenza vaccines."

In the next two months, Baxter will begin enrolling more than 600 patients in the final clinical trial. This time, each will get the same 7.5-microgram dosage without adjuvant, rather than past testing that has involved some patients receiving larger dosages as well as vaccine that includes adjuvant.

The lower dosage of vaccine is considered important should there be an outbreak because companies might be required to quickly ramp up manufacturing capacity and increase the possibility that a greater number of people can be immunized.

Last year, Baxter won a contract from the United Kingdom to make more than 2 million doses of a cell-based vaccine British health officials hope to use as a preventive measure for avian influenza. The company has also signed stockpile agreements with an undisclosed number of other countries, but said those health ministries do not want their names released publicly.

Baxter executives said other governments it has talked to are cautious about stockpiling because it is difficult to predict whether the product they are buying would work against the particular strain of the H5N1 virus that might hit their country. The progress of Baxter's vaccine in clinical trials will help in negotiating more contracts, said Noel Barrett, Baxter's vice president of research and development for the company's vaccine business.

The price of Baxter stock rose 46 cents a share, to $53.22, on the New York Stock Exchange. The company's share price has jumped more than 40 percent over the last year.