US group: Merck wrongly relied on Vioxx animal data

By Lisa Richwine

WASHINGTON (Reuters) – Merck & Co. Inc. knowingly put
patients at risk by relying on limited animal studies to claim
its arthritis drug Vioxx would not harm the heart and ignoring
human data that suggested otherwise, a U.S. advocacy group said
on Thursday.

The Physicians Committee for Responsible Medicine, which
promotes alternatives to animal testing, filed a lawsuit
against Merck on Tuesday on behalf of a member who claims Vioxx
caused her congestive heart failure.

The group said at a news conference on Thursday that it
believed the suit, filed in New Jersey, was the first against a
U.S. pharmaceutical company for relying on animal tests.

Merck, based in New Jersey, disputed the allegations in a
statement issued on Thursday, saying it based its analysis of
Vioxx on “multiple sources involving extensive human trials.”

Merck pulled Vioxx from the market in September 2004 after
a study showed the drug doubled heart attack and stroke risk in
patients who took it for at least 18 months.

A June 21 memo from Merck to the physicians group detailed
a study of African green monkeys designed to compare the
ability of various pain relievers to prevent blood clots. In
the study, the drug naproxen appears similarly effective to
aspirin, which has been shown to reduce the risks of heart
attacks and strokes.

The physicians group said it received the memo from Merck
in response to a request for information about the effects of
naproxen in animal studies. The group released the memo to
reporters on Thursday.

The group said in its lawsuit and at the news conference
that Merck relied on the animal research when a 2000 human
study called Vigor linked Vioxx to more cardiovascular problems
when compared to naproxen.

Merck has argued that Vioxx patients had more cardiac
problems only because the drug did not have the
heart-protective effects of naproxen.

At least nine of 11 other studies in rats and mice showed
Vioxx helped the heart, the physicians’ group said at the news
conference.

But Dr. John Pippin, a cardiologist and consultant to the
physicians’ group, said that human studies had shown no
heart-related benefit from naproxen, and that Merck was aware
that animal studies often do not predict what will happen in
people.

“Merck was wrong to rely on data from mice, rats and
African green monkeys when faced with compelling evidence that
human patients are at risk,” Pippin said.

Merck, in its statement on Thursday, said it was
“inaccurate to suggest that Merck relied on a single animal
study” to demonstrate naproxen protected the heart.

The company pointed to human tests published in the 1990s
and in 2000 that showed anti-clotting effects for naproxen and
similar compounds.

“We believed that the weight of the evidence supported
naproxen’s ability to provide a cardioprotective effect by
blocking platelet aggregation,” or clotting, Merck said.

Vioxx does not stop blood clots from forming, and that was
noted on the drug’s label and labels of similar medicines,
Merck said.