FDA gives MedImmune OK on new way to make FluMist

Md. biotech to use `reverse genetics'


A technique widely used to produce possible pandemic flu vaccines will soon be used to make at least one seasonal version: MedImmune Inc. announced yesterday that the U.S. Food and Drug Administration has given it the go-ahead to create its nasally inhaled FluMist using "reverse genetics."

Though the manufacturing process won't affect the FluMist's formulation or the way it is administered, the technique is thought to be a more efficient and reliable means of production - faster and safer than the current standard. The company says it will be the only vaccine on the market using this technique.

MedImmune, based in Gaithersburg, is hoping that others will follow its lead and license the technology.

"The technique allows the rapid generation of seed viruses for vaccine candidates that exactly match the anticipated epidemic strain," said congressional testimony from Dr. Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases - or NIAID.

The typical way of making flu vaccines - called "classical reassortment" - dates to the 1960s and requires a lot of time-consuming guesswork by scientists. It involves injecting two flu strains into a fertilized chicken egg, where they mix and multiply into as many as 256 gene combinations. Researchers then sort through all of those combinations to find the one they want to manufacture as that season's vaccine.

In reverse genetics, scientists can specifically construct the combination of flu strains they need. They do this by splicing genes together and manufacturing the seeds of the vaccine in mammal cells - in MedImmune's case, kidney cells from an African green monkey. They also can remove any harmful pieces of the flu virus and modify its reproduction rate.

MedImmune has been working with NIAID to create a library of pandemic flu vaccines from which mass amounts could be made if a pandemic occurred.

The company also has offered to license its reverse genetics technology to others. In December, MedImmune acquired the final exclusive license to the last of four intellectual property portfolios that govern the use of reverse genetics in making human flu vaccines. That means anyone else who wants to get in on it has to get the company's permission first.

"It's a technological improvement over the way things are done today," said Philip Nadeau, a biotechnology analyst with S.G. Cowen & Co. LLC. "It seems to me they should be interested in licensing." He does not own stock in MedImmune, nor does his company have an investment relationship with MedImmune.

Nadeau also said the technology should help MedImmune "improve the reliability of FluMist's production."

FluMist's record has been marked by disappointing sales, overproduction and under-adoption.

A second-generation of the vaccine, called CAIV-T, , is under development, and should be ready by the 2007-2008 flu season. MedImmune is hoping CAIV-T doesn't have the same problems that FluMist has encountered. That version was approved for a limited population, and some had concerns that the live virus it's based on would make them sick.

MedImmune's stock closed up a penny to $26.61 on the Nasdaq yesterday.

Though reverse genetics is considered something of an advance in the flu-vaccine world, it hasn't revolutionized the process. It still relies on chicken eggs to reproduce enough of the vaccine to provide doses for the population, a process that President Bush called "antiquated" last year.

Several groups are trying to develop a cell-based production process that would take the chickens out of the mix. MedImmune has been given a $170 million contract from the U.S. Department of Health and Human Services to study the possibility of producing the vaccine using cells such as the monkey's, which would make it available to people who have poultry allergies and can't receive the vaccines.

"That's still several years away from being a tangible product, but there's a lot of work going on right now." said George W. Kemble, vice president of research and development at MedImmune Vaccines Inc., a Mountain View, Calif.-based arm of the Gaithersburg biotechnology company.

Last fall, Bush asked Congress for several billion dollars to develop a "crash program" of cell-based manufacturing for pandemic influenza vaccines. The technique has been used since the 1950s to create vaccines for diseases, including polio, measles and mumps.

But flu vaccine manufacturers have avoided it, sticking with the tried and true egg method, in part because changing the system will likely cost billions of dollars.


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