When Did Merck Know Vioxx Was Deadly?
Study Finds Danger Signal in Early Merck Data; Merck Says Study Flawed
Nov. 23, 2009 - Merck should have known Vioxx was deadly years before they
pulled the drug from the market, a study of Merck's own data suggests.
The study, published in the current issue of the Archives of Internal
Medicine, is by Joseph S. Ross, MD, of Mount Sinai School of Medicine, and
colleagues. The study authors were paid consultants to plaintiffs' lawyers in
Vioxx lawsuits -- in which much of the Merck data first was revealed.
"By our analyses, the association is clear that by June 2001 -- more than
three years before the drug was eventually taken off the market -- the risk
could have been known," Ross tells WebMD.
Merck took Vioxx off the market in November 2004, after the "APPROVe" study
conclusively demonstrated that Vioxx users had more heart
attacks and strokes than patients receiving a placebo.
In their study of data from Merck-sponsored clinical trials, Ross and
colleagues found that:
- By December 2000, data from 21 trials showed that the risk of a heart- or stroke-related adverse event
(a cardiovascular thromboembolic event or CBT) or death (from all causes) was
twice as high in Vioxx patients -- but the finding was just shy of statistical
significance, meaning it could have been a chance finding.
- By June 2001, pooled data showed Vioxx increased the risk of a CBT adverse
event or death by 35% -- a statistically significant finding, meaning it is
unlikely to be a chance finding.
- By April 2002, adding new studies to the pooled data showed Vioxx increased
the risk of CBT or death by 39%, a statistically significant finding.
- By September 2004, adding new studies to the pooled data showed Vioxx
increased the risk of CBT or death by 43%, a statistically significant
In a written statement and in an interview with WebMD, Merck says the study
is flawed. It maintains that the company acted responsibly both in conducting
safety studies and in pulling the $2 billion per year drug from the market as
soon as it was aware that the drug increased the risk of heart attack and
"We fundamentally disagree with their conclusions that there was an
actionable signal before September 2004," Doug Watson, PhD, senior director of
medical science for Merck Research Laboratories, tells WebMD.
Watson says that when Merck looked at the data, its researchers were much
more thorough than Ross and colleagues. Most importantly, Watson says, the
company used independent evaluators to determine whether adverse events were
truly related to heart attack or stroke, and whether deaths were due to heart
attacks or strokes or to non-Vioxx-related causes such as infections or
"We disagree with their conclusions that there was a finding that should
have resulted in earlier action on our part, because we disagree with the
methods they use," Watson tells WebMD. "We investigated Vioxx while it was on
the market ... based on the most rigorous scientific methods, vetted with the
FDA, and we did not see a signal prior to the APPROVe study."