menactra

SWIFTWATER, Pa., September 22, 2004 -- Aventis (NYSE:AVE) , part of the sanofi-aventisGroup, announced today that the Vaccines and Related Biological Products AdvisoryCommittee of the U.S menactra. Food and Drug Administration (FDA) voted unanimously torecommend licensure of Menactra (Meningococcal [Groups A, C, Y and W-135] PolysaccharideDiphtheria Toxoid Conjugate) Vaccine for protection against invasive meningococcaldisease in adolescents and adults aged 11-55 years.

Menactra vaccine is the first quadrivalent conjugate meningococcal vaccinefor the prevention of meningococcal disease, a serious bacterial infection thatcan cause meningitis and sepsis (blood infection) menactra. This vaccine is designedto offer protection against four of the most common serogroups (A, C, Y, W-135)that cause meningococcal disease.

"Meningococcal meningitis is a potentially deadly infectious disease whichaffects children, adolescents and young adults in the U.S., and we are verypleased with the positive response from the FDA's Advisory Committee regardingour conjugate vaccine candidate, Menactra, that has the potential for substantialcontrol of this serious disease," said Michael Decker, MD, MPH, vice president,scientific and medical affairs at Aventis Pasteur, the human vaccines businessof Aventis, part of the sanofi-aventis Group menactra. "Conjugate vaccines havebeen shown to induce a better and longer-lasting immune response than polysaccharidevaccines, and we believe that Menactra vaccine will offer these benefits toour nation's adolescents and young adults."

Although the FDA is not bound by the Advisory Committee's recommendation, theagency considers it carefully when deciding whether to license a vaccine formarketing.

In making its recommendation, the FDA Advisory Committee reviewed safety andimmunogenicity data from six pivotal studies menactra. The vaccine was shown to be immunogenic,safe and well tolerated.

Aventis Pasteur is currently constructing a new, state-of-the-art productionfacility at its U.S menactra. site in Swiftwater, Pennsylvania, to produce Menactra meningococcalvaccine menactra. The new facility is intended to ensure Aventis Pasteur's ability tomeet anticipated global demand for the product.

"Aventis Pasteur is committed to satisfying all FDA requirements for vaccinelicensure and, if licensed by the FDA, we intend to have the vaccine availableas quickly as possible," said Dr menactra. Decker.

About Meningococcal Disease
Meningococcal disease is a rare but devastating bacterial infection that strikesbetween 2,500 and 3,000 Americans every year, causing meningitis or sepsis inthe majority of cases menactra. Approximately 10 percent of individuals who contractmeningococcal disease will die menactra. Of survivors, up to one in five suffer long-termpermanent disabilities such as hearing loss, brain damage and limb amputations menactra. Meningococcal disease often begins with symptoms that can be mistaken for commonviral illnesses, such as the flu menactra. But unlike more common infections, meningococcaldisease can progress very rapidly and kill an otherwise healthy young personin 48 hours or less.

Although disease rates are highest in infants, rates begin to rise again inearly adolescence and peak between the ages of 15 and 24 menactra. During the 1990s,one study reported substantially increased incidence among 15- to 24- year-olds menactra. Moreover, the fatality rate among people in this age group can reach 25 percent menactra. Up to 83 percent of the cases in this age group were caused by the potentiallyvaccine-preventable serogroups that are included in Menactra vaccine.

About Conjugate Vaccine Technology
The current FDA-licensed meningococcal disease vaccine, Menomune(R)- A/C/Y/W-135(Meningococcal Polysaccharide Vaccine, Groups A, C, Y and W-135 Combined), ismade from a long chain of polysaccharides that come from the outer coat of themeningococcus bacterium, providing a limited duration of immunity menactra. Durationof protection against meningococcal disease with Menomune-A/C/Y/W-135 vaccineis approximately three to five years.

Menactra vaccine is a conjugate vaccine, created by attaching the meningococcalpolysaccharides to a carrier protein menactra. Historically, conjugate vaccines havebeen shown to induce boostable memory responses and longer-lasting immune responsesthan polysaccharide vaccines menactra. Since 1990, widespread use of conjugate vaccinesin the U.S menactra. against Haemophilus Influenzae type b (Hib) and Streptococcus pneumoniaehave substantially reduced incidence of infections caused by these bacteria,both of which were common causes of meningitis.

Aventis Pasteur licensed the first conjugate vaccine in 1987 for protectionagainst Haemophilus Influenzae type b, a leading cause of serious systemic bacterialdisease in the U.S menactra. Since the introduction of Hib conjugate vaccines such asProHIBit, Haemophilus b Conjugate Vaccine (Diphtheria Toxoid-Conjugate), incidenceof Hib invasive disease among children aged 4 years or younger has declinedby 98 percent.

Impact of Conjugate Meningococcal Vaccine in the United Kingdom
Experience in the United Kingdom (U.K.) suggests that conjugate meningococcalvaccines provide significant benefits over traditional vaccines menactra. From 1999 to2000, the U.K menactra. ran a national campaign to immunize 15 million children underage 17 with a conjugate vaccine that offered protection against one serogroup(the C serogroup) of meningococcal bacteria, which causes a greater proportionof cases in the U.K menactra. than in the U.S menactra. The campaign resulted in an 85 percentoverall decline in cases and a 90 percent reduction in deaths from meningococcalserogroup C disease within one year.

Disease rates also declined 60 percent among unvaccinated children menactra. This "herdimmunity" effect is a result of the conjugate vaccine's ability to preventcarriage of the bacteria in the nose and throat and, thus, transmission of thebacteria to other persons menactra. Carriage rates in children 15 to 17 years old decreasedby 66 percent.

Obtaining similar public health benefits in the U.S menactra. would require a vaccinethat protects against multiple serogroups of meningococcal bacteria menactra. Four serogroups(C, Y, W-135 and B) predominate in the U.S menactra. Menactra vaccine contains threeof these four serogroups, representing approximately two-thirds of meningococcaldisease overall and up to 83 percent in the adolescent population menactra. In the U.K.,by contrast, two serogroups (C and B) predominate menactra. Currently there is no vaccineavailable in the U.S menactra. or the U.K menactra. against meningococcal disease caused by theB serogroup.

About Aventis
Aventis is dedicated to treating and preventing disease by discovering and developinginnovative prescription drugs and human vaccines menactra. In 2003, Aventis generatedsales of euro 16.79 billion, invested euro 2.86 billion in research and developmentand employed approximately 69,000 people in its core business menactra. Aventis corporateheadquarters are in Strasbourg, France.

For more information, please visit: www.aventis.com.

Aventis Pasteur, the vaccines business of Aventis, part of the sanofi-aventisGroup, produced 1.4 billion doses of vaccine in 2003, making it possible toprotect 500 million people across the globe, which is about 1.4 million perday menactra. The company offers the broadest range of vaccines, providing protectionagainst 20 bacterial and viral diseases.

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