SmithKline Beecham announced Friday that FDA's VaccinesAdvisory Committee reviewed safety and efficacy data on thecompany's hepatitis A vaccine, Havrix, and concluded that thevaccine produces immunity.

The committee did not consider whether the vaccine should beapproved, but debated the issue of what diagnostic test wouldbe the appropriate measurement of efficacy. "The core issue ofthe discussion was whether the currently licensed diagnostictest was sufficiently sensitive to differentiate the outcome ofvaccination," SmithKline said.

"A consensus was established that existing IgM data combinedwith certain clinical measures of liver damage support clinicalefficacy in the Thai study," said the company. More than19,000 children were treated in the Thai trial.

The committee also discussed whether the safety of Havrix hadbeen adequately demonstrated. Although the committee didnot vote, SmithKline said the sense of the committee was thatthe vaccine is safe.

SmithKline reported that in three clinical studies involvingnearly 500 healthy adult volunteers given a single dose ofHavrix, "antibodies against hepatitis A were elicited in morethan 96 percent of subjects one month after vaccination." Inaddition, the company said that in six clinical trials involving1,100 children aged 1 to 18, "99 percent of subjects developedantibodies following two doses."

SmithKline of Philadelphia submitted a product licenseapplication (PLA) for Havrix in June 1992. The vaccine ismarketed in more than 25 countries, including the UnitedKingdom, France, Italy, Germany and Switzerland. Havrix is theonly vaccine for hepatitis A that has been approved in anycountry.

SmithKline's hepatitis B vaccine, Ernergix-B, which it developedwith Biogen Inc., is currently marketed in the U.S., andSmithKline is collaborating with Genelabs Technologies Inc. on ahepatitis E vaccine.

-- Brenda Sandburg News Editor

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