Bextra recall insufficient; Celebrex recall needed too

Patients taking the arthritis drug celecoxib (Celebrex) have a similar risk of heart attacks and stroke as those taking the withdrawn drug rofecoxib (Vioxx), according to a new study by the New Zealand Intensive Medicines Monitoring Programme (IMMP). A recent decision by the FDA banned Bextra but Celebrex only got a black box warning despite calls from numerous quarters for a recall of Celebrex as well.

According to the research published in the international journal Drug Safety, the University of Otago (New Zealand) study is an interim analysis following up approximately 11,000 of the 60,000 patients prescribed either medicine during 2001. Patients’ doctors were asked to supply information about adverse clinical events that occurred since being prescribed the drugs. The study shows that in the patients who had been followed up, there was no significant difference in the risk of thrombotic cardiovascular events (heart attacks and strokes) in patients taking celecoxib compared with those taking rofecoxib, says IMMP Head and study principal investigator Dr Mira Harrison-Woolrych.

In September 2004, Merck, the manufacturer of the COX-2 inhibitor drug rofecoxib (Vioxx) withdrew the product from the worldwide pharmaceutical market because of concerns about serious cardiovascular risks. (Related article: Vioxx recall history) This raised concerns as to whether celecoxib (Celebrex), the most popular alternative to rofecoxib, carries the same risks as rofecoxib. Or whether the increased risk of cardiovascular events seen with rofecoxib is confined to that agent or whether it is a class effect. “The lack of long-term, prospective data has made analyzing this problem very difficult,”said Rosie Stather, Editor of Drug Safety. “That is why this IMMP study is so important – it is a post-marketing study in a “real-life” setting, where there are none of the exclusion criteria that apply in the highly-controlled environment of a clinical trial.” Pfizer has always argued that despite Celebrex and Bextra being Cox-2 drugs, they are different from Vioxx at the molecular level. The FDA did not buy this argument and has forced Pfizer to recall Bextra and has imposed severe restrictions on Celebrex prescriptions. Pfizer refuses to agree with the FDA. (Related article: Bextra recall is no gain for Celebrex)

The IMMP is a national unit, based at the University of Otago and funded by the New Zealand Ministry of Health, which monitors the safety of specific medicines after they are licensed for use in New Zealand. The IMMP has been monitoring the safety of COX-2 inhibitors since 2001. The IMMP is one of only two monitoring programs in the world that proactively studies the safety of newly marketed drugs. This study will further intensify calls for recall of Celebrex as well.

“It was important to perform this interim analysis at this time, as the withdrawal of rofecoxib sparked world-wide concerns about the safety of celecoxib. This is the first study to directly compare the cardiovascular risks of celecoxib with rofecoxib in a ‘real-life’ post-marketing setting,” says Dr Harrison-Woolrych. “However, while this group of 11,000 patients is clearly defined and reasonably large, it should be understood that it may not be large enough to detect small differences in the rate of relatively uncommon events, such as heart attacks and strokes,” she says. Dr Harrison-Woolrych commented that the IMMP has been able to do this comparative study as both rofecoxib and celecoxib were monitored at the same time in New Zealand. “It was however important to adjust the results for differences between the two groups - for example, the celecoxib cohort was older and more likely to be taking the medicine long term,” she added.

The Editor of the journal Drug Safety, Ms Rosie Stather, commented that the results from the IMMP study were an important contribution to the growing international evidence on the safety of COX II inhibitors. “Together with information from other studies, the IMMP results will assist healthcare decision-makers in assessing the advantages and disadvantages of celecoxib in order to make recommendations regarding its use,” Ms Stather says.

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