Merck & Co. Inc. receives FDA license to market Vaqta, hepatitis A vaccine.

WEST POINT, Pa.--(BUSINESS WIRE)--April 2, 1996--Vaqta(R) (Hepatitis A Vaccine, Inactivated), a new vaccine developed by Merck & Co. Inc. for the prevention of hepatitis A, has been licensed by the U.S. Food & Drug Administration (FDA).

The product will be available in May. Vaqta is indicated for active immunization against disease caused by hepatitis A in persons two years of age and older. Hepatitis A is a highly contagious virus that attacks the liver and can cause victims to be ill for several weeks.

Approximately 27,000 cases of the disease were reported to the U.S. Centers for Disease Control and Prevention (CDC) in 1994. However, the CDC estimates there are approximately 143,000 hepatitis A infections in the United States each year and 1.4 million worldwide annually.

While children often harbor the disease without overt symptoms, adults over 50 years of age are at higher risk for severe symptoms. About 22 percent of adults who contract hepatitis A require hospitalization.

The costs for treating and controlling outbreaks of hepatitis A in the U.S. were estimated to be $200 million in 1987. An estimated 100 people die from hepatitis A in the U.S. every year. Three individuals died in a hepatitis A outbreak in Shasta County, Calif., in late 1995.

Gordon Douglas, M.D., president, Merck Vaccine Division, in announcing the licensure of the vaccine noted that it marks a significant milestone in the company's leadership in vaccine development. "Vaqta offers the very real possibility that we will be able to eradicate yet another disease that is of great public health concern.

"We have led the way in the past with measles and polio and look forward to the day when no one has to have a concern about hepatitis A."

Discovered and developed by scientists at Merck & Co. Inc., over the past 20 years, Vaqta was observed in a clinical study to provide 100 percent protection against hepatitis A 50 days or more after vaccination.

In addition, no cases of hepatitis A were reported in vaccinees in this study after day 16. In its use in 9,181 healthy children, adolescents and adults to date, it has been generally well tolerated. Adverse reactions were mild and self-limited, consisting mainly of local reactions at the injection site within 24 hours of vaccination.

Because there is no treatment for hepatitis A and the medical and economic consequences of the disease are substantial, immunization of high risk individuals is recommended by the CDC. These individuals include members of ethnic and geographic communities that experience cyclic hepatitis A epidemics, military personnel, male homosexuals, users of illicit drugs, those with chronic liver disease and anyone traveling to parts of the world in which the disease is endemic.

Also at risk are certain institutional workers, such as those who care for the developmentally challenged, employees of child day-care centers, laboratory workers who handle live hepatitis A virus and handlers of primate animals that may be harboring HAV. Blood borne transmission, while uncommon, is possible via blood transfusion, contaminated blood products or needles shared with an HAV infected individual.

Vaqta is one of two hepatitis A vaccines available in the U.S. Two doses of Vaqta are required for children, versus three for the other product. Individuals two through 17 years of age should receive a single 0.5 mL dose of vaccine and a booster dose of 0.5 mL 6 to 18 months later. Adults 18 years of age and older should receive a single 1.0 mL dose and a booster six months later.

A Serious Disease

The U.S. Centers for Disease Control and Prevention (CDC) reports that hepatitis A (HAV) is an important public health problem in the U.S. and that use of hepatitis A vaccine has the potential to significantly decrease the incidence of the disease around the world.

The CDC further reports great similarity between the epidemiology of hepatitis A and polio, suggesting that widespread vaccination of appropriate susceptible populations can substantially lower disease incidence, eliminate virus transmission, and ultimately eradicate HAV.

Common signs of the illness include a sudden onset of influenza-like symptoms such as fatigue, nausea, vomiting, fever, jaundice, dark urine, light-colored stools and abominable pain in the area of the liver. Although most patients begin recovery within three weeks, some have prolonged or relapsing symptoms for up to six months.

HAV is most commonly transmitted by the fecal-oral route, through close person-to-person contact, or by ingestion of sewage contaminated food or water. Severity of HAV disease increases with age.

With no specific treatment available for any type of acute viral hepatitis, HAV must run its course. When symptoms are mild, treatment is limited to bed rest and appropriate nutrition. Adult patients may be quite ill for two to three months, and full recovery can take up to a year.

Among those infected in the U.S. between 1990 and 1992, 11 percent of children under 15 years of age were hospitalized, while 22 percent of patients over 15 were hospitalized. Adults infected with HAV lose an average of 27 days from work.

Because HAV can be a long, costly illness that may have serious consequences, immunization is recommended for individuals at risk of exposure. Immune serum globulin traditionally has been used to prevent hepatitis A, but it confers pre-exposure protection for just three to five months.

Post-exposure inoculation is often too late to be effective. The development of hepatitis A vaccine permits both short and longer-term protection.

Vaqta is contraindicated in individuals with known hypersensitivity to any component of the vaccine. In healthy children and adolescents studied in clinical trials, the most common systemic complaints included headache (0.4%), abdominal pain (1.2%), and pharyngitis (1.2%).

Who Is At Risk

Several groups are considered at risk of HAV infection, based on demographics, travel patterns, work experience and sexual activity. In the U.S., epidemics sometimes lasting for several years have occurred in certain communities where 30 to 40 percent of children under 5 years of age are infected.

These include American Indian, Alaskan native, Hispanic and certain communities in which poor sanitation, overcrowded living conditions and other factors contribute to the high disease incidence. The disease is prevalent in the Southwestern U.S. border states, Alaska, Latin America, Africa, the Middle East, India and Southeast Asia.

In 1995, the CDC noted that active pre-exposure immunization to HAV infection holds the possibility of eliminating the disease and recommended that children in communities with high rates of infection and periodic outbreaks be routinely vaccinated. The CDC suggests that the most effective method for achieving this goal may be to add HAV vaccine to the routine childhood vaccination schedule.

Development of Vaqta

Vaqta is an inactivated whole virus vaccine. It is the product of more than 20 years of basic and developmental research by Merck scientists. It is manufactured by a multi-stage process developed at Merck Research Laboratories that utilizes state-of-the-art biotechnology methods.

Vaqta is supplied in prefilled syringes and vials. The vaccine is manufactured at the company's West Point, facility, and is marketed by the Merck Vaccine Division.

Merck & Co. Inc. is a leading research-driven pharmaceutical products and services company. Merck discovers, develops, manufactures and markets a broad range of innovative products to improve human and animal health.

The Merck-Medco Managed Care Division manages pharmacy benefits for more than 40 million Americans, encouraging the appropriate use of medicines and providing disease management programs. Through these complementary capabilities, Merck works to improve quality of life and lower overall healthcare costs. -0- NOTE: Prescription information to follow as (MERCK-2). -0- Vaqta is a Merck & Co. Inc. trademark for hepatitis A vaccine, inactivated.

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