Vaccine Approval Boosts Merck

Merck & Co. has won Food & Drug Administration approval to market the first vaccine to protect roughly 41 million older Americans from shingles, a painful disease caused by the reactivation of the virus that causes chicken pox.

“Approval of a vaccine against shingles represents a major public health advance for people 60 and older,” says William Schaffner, professor of preventive medicine at the Vanderbilt University School of Medicine in Nashville. The vaccine, cleared on May 26, will be sold under the brand name Zostavax.

The potential market for Zostavax is quite large. According to Merck, more than 90% of adults in the U.S. have been infected with chicken pox and are at risk for developing shingles. The incidence and severity of the disease and its complications increase with age. About half of the estimated 1 million cases of shingles that occur in the U.S. each year occur in the elderly.

“Zostavax is unique, because in contrast to other vaccines that help prevent a primary infection, it helps prevent reactivation of a virus that’s already inside the body,” says Ann M. Arvin, professor of pediatrics, infectious diseases, and microbiology and immunology at Stanford University School of Medicine.

The Zostavax approval is more welcome news for Merck, which is facing thousands of lawsuits as it struggles to recover from the recall of its blockbuster painkiller, Vioxx. Earlier this month, an FDA advisory committee endorsed the effectiveness and safety of Gardasil, a Merck vaccine designed to prevent cervical cancer. And in February, the company won U.S. approval for RotaTeq, its vaccine against rotavirus, the most common cause of severe diarrhea in children.

FDA approved Zostavax after a clinical study involving 38,000 people found that the vaccine reduced outbreaks of shingles by 50% among those 60 or older, and by 64% among those between the ages of 60 and 69.

“This vaccine gives health care providers an important tool that can help prevent an illness that affects many older Americans and often results in significant chronic pain,” says Jesse L. Goodman, director of FDA’s Center for Biologics Evaluation & Research.

Zostavax, which will be manufactured at Merck’s West Point plant outside Philadelphia, is an injected adult version of the company’s chicken pox vaccine. Merck says the new vaccine works by boosting the immune system’s ability to suppress the virus in nerve roots. A single dose of Zostavax will initially cost about $145 a vial, according to the company.

Because some older people may not be able to pay that price, Merck also announced a new patient assistance program to make all of its adult vaccines available free of charge to low-income uninsured people. The company says Zostavax and its other vaccines will become available through this program in the third quarter of 2006.

Zostavax was approved for sale in the European Union and in Australia earlier this month. Merck says it will begin to commercialize the vaccine outside of the U.S. in 2007.