Yet Another Study Confirms That Higher Doses of Celebrex Are Associated with Increased Risk of Heart Attack and Stroke

On March 31, 2008, a study funded by the
National Cancer Institute, was published in the medical journal Circulation
and analyzed data from six separate studies involving nearly 8,000 patients
concerning the safety of the drug Celebrex. 
Data showed that patients who took two 400 mg doses of Celebrex daily had a three times (or 300%) higher risk of suffering heart
attacks, strokes, heart failure, blood clots, and cardiovascular death.  An
interesting finding was that patients who took 200 mg doses of Celebrex had a
higher risk of nearly 200% of suffering cardiovascular injuries than patients
who ingested the same 400 mg daily but in a single dose, which may be
attributable to a relatively small number of patients who ingested Celebrex
pills only once a day.   The risks were more significant in patients who had
other cardiovascular risk factors, such as diabetes and heart disease.   There was no data analyzed regarding
the risks that might be associated with use of Celebrex at 200 mg per day, the
most common dose used by patients in light of all of the recent information
regarding the significant cardiovascular risks of all of the Cox-2 inhibitors
(Vioxx, Bextra, Celebrex, and Arcoxia). 

Celebrex is a Cox-2 inhibitor that already
carries a “black box” warning regarding heart attack and stroke risk, which,
along with the demise of Vioxx, led to a 50% decrease in the sales ofthe popular
arthritis drug.  The American Heart Association guidelines indicate that people
should take Celebrex as a “last resort” and for the shortest time possible
because of the risks of heart attack and strokes. 

A Pfizer spokeswoman commented on the study in a
Bloomberg.com report and tried to distance Celebrex from Vioxx (despite
consistent reports of similar cardiovascular risks) and instead attempted to
reassure patients that the risks reported in this study are “consistent with
Celebrex’s current prescribing information.”  The Bloomberg.com report also
notes that Pfizer is having difficulty recruiting patients for ongoing studies
to determine whether Celebrex is safe for use at the lowest doses that are
currently recommended due to “negative publicity surrounding the category of
drugs.”  Additional studies are anticipated in 2010 or 2011 that would perhaps
provide further answers regarding the safety of Celebrex at the most commonly
prescribed doses as compared to ibuprofen and
naproxen.  

This new study and Pfizer’s response lead to a number of
questions:

     1.    Are prospective study participants receiving
better information than patients about the risks of Celebrex since extensive
informed consent is required prior to entry into a study?  Pfizer focued on the
“publicity”, but it is hard scientific data – not editorials – that are pointing
to serious safety issues with respect to Celebrex.  Thankfully, the “publicity”
has reached at least half of patients who chose to dump Celebrex because the
risks of the drugs outweighed any benefit.  One can only wonder whether the
other 50% of patients who remained on Celebrex and purchased $2.3 billion of the
drug in 2007 made rational personal choices to remain on the drug or just
did not have access to adequate information of their medications.  Is it
sufficient for this type of risk information to be buried in a label that most
patients never see? 

    2.    Why don’t we know more about the risks of
Celebrex by now? The arthritis drug was approved for sale in this country in
1999, and was the first Cox 2 inhibitor introduced in the United States.  The
latest reports indicate that the studies that might provide some answers on
whether the drug is safe at the most commonly-used doses won’t be available
until more than a decade after its approval by the FDA.  Is it acceptable to
permit patients to serve as guinea pigs for the 10-year or more run on a new
drug?  Finally, will we ever see the much-anticipated safety studies on
Celebrex, or will the drug fade away just prior to expiration of the patent and
prior to completion of critical safety studies? 

I guess we will just have to wait until 2011 to see.