The world’s largest pharmaceutical company, Pfizer, has defended itself in the wake of allegations earlier this week from influential US consumer group, Public Citizen, that it hid data from a 1999 clinical trial, which highlighted a potential safety risk amongst patients taking its Celebrex (celecoxib) painkiller [[01/02/05b]]. The firm says it “vigorously refutes the claims” that it failed to disclose the data, and calls Public Citizen’s charges “misleading and unfair to patients.”

The company says that the study, which was designed to assess the potential of Celebrex in slowing Alzheimer’s disease progression, but showed that Celebrex did not significantly influence the course of the disease, was monitored by an independent safety panel. In addition, it notes that an abstract of the results was presented at a scientific congress in 2000, and the completed study report was submitted to the US Food and Drug Administration in June 2001.

“Pfizer acted responsibly in sharing this information in a timely manner with the FDA,” said Dr Joseph Feczko, Pfizer president of worldwide development said in a statement. “Public Citizen’s cherry-picking of data is alarmist and misconceived,” he added. “It is not possible to draw clinically meaningful cardiovascular conclusions from this study alone given the variations in patients’ medical history, their advanced age and other significant study limitations. This flawed use of data is misleading and unfair to a reasoned scientific discussion of these issues.”

The firm says that a vast amount of data supporting the safety of Celebrex in arthritis patients, but acknowledges that patients who received Celebrex in this particular trial experienced more cardiovascular side effects than placebo. It attributes this to a large difference in the underlying CV risk profile of the patients assigned to Celebrex treatment, versus those who received placebo – for example, more patients in the Celebrex group had hypertension, or had undergone a previous heart by-pass surgery than those patients taking placebo.

Later this month, an FDA advisory committee will begin a rigorous scientific evaluation of the risks and benefits of all COX-2 medicines, including Celebrex and another Pfizer product, Bextra (valdecoxib), after the safety of this class of medicines was questioned as a result of Merck & Co’s decision to withdraw Vioxx (rofecoxib) last year after clinical trial data showed a heightened risk of heart attack amongst Vioxx users versus placebo [[01/10/04a]].