December 14, 2005

Merck vaccine reduces shingles -U.S. FDA staff

By Susan Heavey

WASHINGTON (Reuters) - Studies show Merck & Co. Inc.'s
experimental vaccine to prevent shingles can cut the rate of
infection by about half in people 60 and older and help curb
related pain, U.S. regulatory staff said in documents released
on Wednesday.

But company data also showed the vaccine, called Zostavax,
did not significantly reduce rates of death or hospitalization
and became less effective after three years, U.S. Food and Drug
Administration staff said before an advisory panel meeting on
Thursday to discuss the product.

Zostavax showed no "particular pattern" of serious side
effects, the staff also said.

The panel of outside health experts will weigh whether to
recommend approval by the FDA, which usually follows its
advisers' advice.

Merck is also seeking approval for another vaccine to help
prevent rotavirus, the most common cause of diarrhea in
children. A panel meeting to discuss that product is being held
on Wednesday.

Shares of Merck rose 2.4 percent, or 70 cents, to $29.60 in
afternoon trade on the New York Stock Exchange.

Shingles is caused by the same virus that triggers chicken
pox -- the varicella-zoster virus -- and is characterized by a
wave of small rash-like blisters on the skin. The virus targets
the nerves and can lead to intense pain.

About 1 million people in the United States develop
shingles each year.

The disease sometimes affects younger people. In late
February 2003, CBS late-night television show host and comedian
David Letterman was sidelined by an eye infection brought on by
a case of shingles, according to his doctor. Letterman was 55
at the time.


Some antiviral drugs can help curb the outbreak and prevent
the pain, all of which can last for up to five weeks on
average. Other drugs, including some antidepressants, steroids
and anticonvulsants, also can help decrease the
outbreak-related discomfort.

Experts have said shingles is more prevalent among older
people, and that more will contract the infection as people
live longer.

In their review, the FDA staff also noted age was a factor
in how well the vaccine worked, saying it was less effective in
people 70 and older.

Viral infections were reduced by 63.9 percent in people 60
to 69 years old, compared with 37.6 percent in those ages 70
and older, they wrote. Illness-related pain dropped by 65.5
percent in 60- to 69-year-olds and by 55.5 percent in those 70
and older.

In separate documents, Merck officials said Zostavax
significantly reduced the incidence of the virus as well as
related complications when compared with placebo.

The vaccine also is "generally well tolerated" in people
age 50 and older, Merck said its report, also released on

Merck tested Zostavax in eight clinical trials, including
one with 38,546 volunteers age 60 and older, about half of whom
received the vaccine. The others took a placebo.

The results, made public in June, found the vaccine cut the
risk of infection in half, with 315 people who received the
vaccine developing the painful disease, compared with 642 in
the placebo group.

Merck also is seeking European approval for the vaccine.

The meeting documents were posted on the FDA's Web site at