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Vaccine Study Lifts MedImmune

Shares are up more than 5%.



climbed Thursday after company-sponsored research showed that the FluMist nasal-spray flu vaccine outperformed a traditional flu shot in young children.

If this late-stage clinical trial helps convince the Food and Drug Administration to expand the use of FluMist, MedImmune will have taken a big step in overcoming the vaccine's disappointing performance.

Shares of the Gaithersburg, Md.-company rose $1.77, or 5.7%, to $33.20 on heavy volume.

FluMist has performed poorly in part because the FDA says it can be used only for healthy people between the ages 5 of and 49, thus excluding the very young and the very old who are most vulnerable to the flu.

The research on younger children was published in the

New England Journal of Medicine

. MedImmune

had briefly described the results in January when it said the FDA had approved an updated version of FluMist. The new vaccine will be available for the 2007-2008 season.

Given the risks and benefits, the


article concluded that FluMist "should be a highly effective, safe vaccine for children 12 to 59 months of age who do not have a history of asthma or wheezing." MedImmune is using this data in asking the FDA to expand FluMist's use.

Despite its touted convenience, FluMist was a commercial failure after it was introduced during the 2003-2004 season for several reasons other than its limited coverage. Many insurers didn't want to pay its higher price and the product was inconvenient to store.

MedImmune believes it has taken care of the storage issue with the FDA's approval of a version called CAIV-T, or cold adapted influenza vaccine-trivalent. This product can be kept in a standard refrigerator, whereas the original FluMist must remain frozen until used.

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article is that young children receiving FluMist, in its CAIV-T form, had 55% fewer cases of flu than those receiving a traditional vaccine. The study examined nearly 8,500 children between the ages of six months and 59 months. It was conducted during the 2004-2005 flu season at 249 medical centers in the U.S., Europe, Asia and the Middle East.

"With only one influenza vaccine currently approved for use in children under the age of 4, options are limited and sometimes hard to come by," said the study's lead author, Dr. Robert B. Belshe, in a Wednesday press release issued by MedImmune. Belshe is director of the Center for Vaccine Development at the Saint Louis University School of Medicine.


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sell traditional flu vaccine in the U.S.. Only Sanofi's Fluzone is permitted for children as young as six months. Novartis' Fluvirin can be given to children as young as 4 years old.

The difference between the MedImmune vaccine and the other vaccines is that FluMist is made with a live, weakened virus and the others are made with an inactivated virus.

"A careful evaluation of the benefits and risks" of the


study "demonstrated that FluMist was highly favorable" for young children, Dr. Edward Connor, MedImmune's chief medical officer, said in a press release.

One red flag is the finding that FluMist was linked to "statistically significantly more hospitalizations for any cause" among children ages six to 11 months, the company said. "A nonsignificant trend toward more hospitalizations in the FluMist group was seen in children 12 months to 47 months of age with a past history of wheezing. These observations require additional study."

However, MedImmune said that among children ages 12 months to 59 months without wheezing problems, "there was a trend, though not statistically significant,

of fewer hospitalizations" for FluMist recipients compared with flu-shot recipients. Among these patients, "the rates of wheezing were not statistically different in children who received FluMist (4.7%) compared to the flu shot (4.9%)," the company said.