Just days before a Food and Drug Administration advisory committee meets to discuss the future of Celebrex, Bextra and related arthritis drugs, the agency's Australian counterpart has introduced tough new measures to limit their use.
Australia's Therapeutic Goods Administration announced Thursday that makers of all COX-2 inhibitor drugs must place a boxed warning on their labels about an increased risk of cardiovascular problems. The agency is also advising patients who take more than 200 milligrams a day to discuss their treatment regimen with their doctor.
The Australian agency began reviewing the safety of COX-2 inhibitors after Merck withdrew Vioxx from the worldwide market Sept. 30. A company-sponsored study found a higher risk of heart attacks and strokes in participants who took Vioxx, compared with those who received a placebo.
Curt Furberg, a member of the FDA advisory panel, says the steps taken in Australia "could be a hint" of what might happen when the panel meets Wednesday, Thursday and Friday.
Although advisory panels only make recommendations, the FDA usually goes along with them. Options range from doing nothing to putting a strong boxed warning on labels to withdrawing the drugs.
Australia also has proposed withdrawing its approval of Bextra for the treatment of arthritis. Susan Bro of Pfizer, maker of Bextra and Celebrex, says the company plans to appeal the agency's plan to limit Bextra, which is not yet sold in Australia, to the treatment of menstrual cramps.
Meanwhile, an Australian study about the effects of Celebrex and Vioxx on blood pressure became the first to be posted online today in advance of publication in the Archives of Internal Medicine.
The study pooled the results of 19 trials comparing COX-2 inhibitors with a placebo or conventional pain reliever, such as ibuprofen or naproxen. The researchers concluded that Vioxx raised blood pressure more than Celebrex did. COX-2 inhibitors' potential effect on blood pressure "requires caution in their use and warrants further investigation," the authors wrote.
"But," says senior author Henry Krum, a Melbourne cardiologist who is a consultant for both Pfizer and Merck, "research about the cardiovascular safety of the older pain relievers is lacking. These drugs, even though they've been around for 30 years, have never really been tested."
FDA whistleblower David Graham, who told a Senate committee in November that the agency is incapable of protecting Americans against another Vioxx, says his superiors have dissuaded him from presenting new data from an analysis of pain-reliever use by California Medicaid patients at the advisory committee meeting. The study, not yet published in a medical journal, is the largest yet to look at heart-attack risk in pain-reliever users, he says. "It sheds light on the risks associated with a number of drugs in addition to the COX-2 agents."
The FDA would not comment on the record about Graham's assertion, the subject of a letter sent Friday by Sen. Chuck Grassley, R-Iowa, to FDA acting commissioner Lester Crawford.