Sanofi Wins U.S. Approval for First Bird Flu Vaccine

Sanofi-Aventis SA won U.S. approval for the first vaccine to protect against bird flu even though the shot may protect less than half of the people inoculated.

The vaccine could be used if the H5N1 strain of avian influenza mutates into a form that can spread easily among humans, the Food and Drug Administration said today. At least 291 people worldwide have been infected with the virus since 2003, and 172 have died, according to the World Health Organization. The virus hasn't appeared in the U.S.

The U.S. government already has bought millions of doses of Sanofi's vaccine for its emergency stockpiles. The shots are worth having until more effective products can be developed, FDA officials said.

``We feel that as part of pandemic preparedness, it would be best to have a licensed vaccine,'' said Norman Baylor, director of the FDA's Office of Vaccines Research and Review, in a conference call today. ``This is sort of an interim measure.''

Data from a clinical trial showed the vaccine raised a protective immune response in 45 percent of study participants, short of the 70 percent goal the FDA set last year for a pandemic vaccine. The vaccine would be given in two 90-microgram shots, about a month apart. Seasonal flu shots normally require about 15 micrograms of viral protein for each strain they protect against.

Sanofi's American depositary receipts, each representing half an ordinary share, fell 5 cents to $46.14 at 4:04 p.m. in New York Stock Exchange composite trading.

Clearance from the FDA will save doctors, hospitals and regulators hours, if not days, that would otherwise be needed to gain permission to use Sanofi's shot in a pandemic, said William Schaffner, a Vanderbilt University infectious disease specialist who advises the U.S. government on vaccines.

`This Simplifies Things'

``Patients would have to sign some kind of waiver,'' Schaffner said today in a telephone interview. ``This simplifies things enormously because now it's a licensed product.''

A panel of FDA advisers voted unanimously at a Feb. 27 meeting in favor of approving the vaccine. Philip Hosbach, vice president for immunization policies and government affairs for Paris-based Sanofi, said the company is working to develop ways to make its vaccine more potent.

The U.S. has bought more than 6 million doses of the vaccine and has indicated that it would like 20 million doses, Hosbach said in a telephone interview today. The vaccine won't be sold commercially.

FDA approval of Sanofi's shot won't change the government's plans to buy enough doses of bird flu vaccine from several drugmakers to protect 20 million people, said Holly Babin, a spokeswoman for the Health and Human Services Department.

Other Suppliers

The U.S. has awarded contracts for a smaller number of shots to Novartis AG, based in Basel, Switzerland, and GlaxoSmithKline Plc of London. Neither of these vaccines has been approved by U.S. regulators.

Some of the Sanofi shots that have been bought have already begun to lose their effectiveness. The Health and Human Services Department said in November that almost a fifth of the shots in its storehouse had begun to lose potency. As a result, the stockpile now contains enough vaccine to fully immunize 3 million people against H5N1, down from the 3.75 million that could have been protected when the shots were new.

Glaxo is developing an H5N1 vaccine using a booster, called an adjuvant, which makes its shot effective in two doses of 3.75 micrograms, almost 25 times smaller than Sanofi's. A more potent vaccine could be extended to protect more people in a pandemic.

``Studies of the use of adjuvants will take some time,'' said Walter Orenstein, associate director of the Emory Vaccine Center at Emory University in Atlanta, in a telephone interview today. ``At least this adds something right away if in fact there's a rapid emergence of H5N1.''

source:www.bloomberg.com