Pfizer Inc. on Friday said two small clinical trials showed heart bypass surgery patients taking Bextra, an anti-inflammatory in the same class as the recently withdrawn drug Vioxx, had a higher risk of stroke and heart attack.
Bextra is approved to treat pain from arthritis and, like Merck & Co.’s Vioxx, is a COX-2 inhibitor. A recent trial showed Vioxx doubled the risk of heart attack and stroke in arthritis patients who took the drug for more than 18 months.
The Vioxx withdrawal has cast a cloud over the entire class of COX-2 inhibitors, which includes Bextra, Celebrex and an experimental drug from Novartis AG called Prexige.
However, Pfizer said that following the Vioxx withdrawal it re-examined its clinical data base of 8,000 patients with rheumatoid arthritis and osteoarthritis and found no increased risk of so-called heart events in patients taking Bextra for up to a year. The company also found no increased risk in a trial of patients taking Bextra in a general surgery setting.
Doctors said it is too early to quantify the potential risk of Bextra or of Pfizer’s other COX-2 inhibitor Celebrex as neither have tested for long enough. Pfizer said it is conducting longer term trials in arthritis patients.
The coronary bypass trials are ones that Dr. Eric Topol of the Cleveland Clinic Foundation and an early and outspoken critic of Vioxx, said he finds concerning as they show a cluster of heart attacks and strokes. But he said the danger signal does not appear to be as strong as it was with Vioxx.
“Celebrex and Bextra do appear safer than Vioxx but whether they are really safe, especially in patients with heart risk, that’s an open question,” Topol said.
Pfizer also said it is updating its label on Bextra to strengthen a warning about a rare but serious skin reaction that can occur mainly within the first two weeks of therapy.