Does Stopping Vioxx Stop the Risk?
Experts, Drug Company Officials Disagree About Long-Term Heart and Stroke Risk
May 12, 2006 - Do strokeand heart attackrisks linked to the drug Vioxx continue after
people stop taking it?
Yes, some leading cardiologists say. No, says Merck, which made Vioxx until
pulling the painkiller off the market in September 2004.
It's not a mere moot point. At stake is the continued safety of the many
people who took the heavily promoted drug before its risks became known.
The battle is over new data from the APPROVe study. The Merck-sponsored
study led to Vioxx's demise. It found that patients taking Vioxx during the
first three years of the study had a 92% higher risk of stroke and heart attack
than those taking an inactive placebo pill.
New "preliminary" data released yesterday by Merck show that in the
year after stopping Vioxx, the 1,721 patients still had a 74% higher
stroke/heart attack risk. During that year, 28 patients who had taken Vioxx --
and 16 patients who had taken placebo pills -- had a stroke or heart attack.
Most of these events were strokes.
This difference isn't statistically significant, meaning it could be a
chance finding. Merck says this means there isn't any risk to people who stop
taking Vioxx -- at least, no scientifically proven risk.
Not so, says cardiologist Steve Nissen, MD, interim chairman of the
department of cardiovascular medicine at The Cleveland Clinic.
"What this means is the relative risk of an event with Vioxx, even after
the drug was stopped, was very similar to the risk while taking the drug,"
Nissen tells WebMD. "It has profound implications for patients. It means
that patients who previously took Vioxx must be followed closely and must be
made aware of their increased risk."
Debate Over Meaning of Data
Michael Farkouh, MD, an expert on the heart safety of the class of drugs to
which Vioxx belongs, is director of cardiovascular clinical trials at Mount
Sinai Medical Center. He largely agrees with Nissen.
"It is concerning there is an ongoing risk from Vioxx," Farkouh
tells WebMD. "I would say the numbers are small, but they suggest an
ongoing risk from Vioxx in those who stopped taking it. There appears to be
this same increase in risk as seen while taking the drug. While the difference
is not statistically significant, it is concerning."
Merck declined WebMD's request for an interview but provided the transcript
of a telephone conference held Thursday for the financial press. During that
news conference, Merck general counsel Ken Frazier said "no significant
risk" means "no risk" in both scientific and legal terms.
"The data do not provide a valid basis or a claim that an event that
occurred after a patient stopped using the medicine was linked to the
drug," Frazier said. "In the off-drug follow-up period for patients in
this study, there was not a statistically significant difference in the risk of
confirmed [strokeor heart attack] events in the
Vioxx group compared to the placebo group. So, from our perspective, we have to
base our responses and our defenses on the data as it was presented, and these
data do not establish statistically significant risk."