October 6, 2005
Merck cervical cancer vaccine prevents lesions
By Ransdell Pierson
NEW YORK (Reuters) - An experimental Merck & Co. vaccine
completely prevented early-stage cervical cancer and
precancerous cervical lesions caused by the two most common
forms of a virus linked to such cancers, Merck said on
"This trial confirms that a vaccine can give young women a
high level of protection from developing precancerous lesions
and early cervical cancers," Laura Koutsky, a professor of
epidemiology at the University of Washington who led the study,
The favorable findings were seen in a late-stage trial
sponsored by the U.S. drugmaker, which included more than
12,000 women from 13 countries, aged 16 to 26, who were not
infected with either of the virus types when the trial began.
The two forms of human papillomavirus, types 16 and 18, are
responsible for an estimated 70 percent of cervical cancer
cases, and are the targets of Merck's Gardasil vaccine. Such
cancers kill about 300,000 women worldwide each year, including
almost 4,000 in the United States, Merck said.
Merck, whose earnings plunged after the withdrawal last
year of its Vioxx arthritis drug, plans later this year to seek
U.S. approval for the cancer vaccine, which also protects
against another two types of the virus that cause genital
warts. Merck is partnering its vaccine in Europe with
Half the women in the Phase III trial received three doses
of Gardasil over a six-month period, while the other women
received placebos. The women were then followed for an average
of 17 months.
Merck said Gardasil was 100 percent effective in preventing
precancerous lesions and early-stage cancers associated with
virus types 16 and 18 among women who remained free of
infection until they received their final dose of the vaccine.
The vaccine thereby easily met its primary trial goal.
By contrast there were 21 cases of lesions and early-stage
cancers associated with the two virus types among those taking
placebos, Merck said.
Although the vaccine was completely protective against the
two virus types, Koutsky said she hoped the vaccine will
eventually be improved to protect against up to another half
dozen types of the virus that cause cervical cancer.
"If that case, you could be blocking viruses that cause 87
percent of cervical cancer cases, instead of 70 percent," she
Industry analysts have said Gardasil could generate peak
annual sales of over $2 billion that could help revive fortunes
of Merck. The company, based in Whitehouse Station, New Jersey,
is facing thousands of lawsuits from former Vioxx users and
their families who claim the withdrawn drug caused heart
attacks and other serious health problems.
Gardasil is slated to compete with GlaxoSmithKline Plc's
experimental Cervarix cervical cancer vaccine, which targets
the same two cancer-causing virus types but is expected to be
approved later than the Merck product. Glaxo's U.S. partner on
its vaccine, which does not protect against genital warts, is