A clinical trial of the blockbuster arthritis drug Celebrex was shut down yesterday after researchers found an increase in the risk of serious heart disease and strokes in those taking the drug, the same side effects that caused the related painkiller Vioxx to be taken off the market this fall.
The manufacturer of Celebrex, Pfizer Inc., gave no indication that it would withdraw its product, saying the new results are at odds with other ongoing and completed clinical trials.
But the Food and Drug Administration's acting commissioner, Lester Crawford, said the agency has "great concerns about this product and this class of products" -- the COX-2 inhibitors that tens of millions of Americans have taken. "We don't have a decision yet on the fate of this product, but we're leaving all regulatory options open," Crawford said.
COX-2 inhibitors were hailed in the late 1990s as a historic advance in arthritis and pain treatment, but the agency is now seriously considering regulatory action to limit their use or remove them from the market. Crawford said that patients using Celebrex should meet with their doctors to discuss possible alternate therapies, and that those continuing on the drug should use the smallest dosage possible.
The worrisome results came from a clinical trial being conducted by the National Cancer Institute into whether Celebrex might protect people at risk of colorectal cancer. Ernest Hawk, chief of gastrointestinal research for the NCI, said a team of cardiovascular specialists had been brought in to help analyze the cardiovascular risk of Celebrex for participants in the trial after Vioxx was withdrawn in late September.
Hawk said the experts, along with the safety monitoring board of the trial, found that patients on 400 milligrams of Celebrex were 2.5 times as likely to have a heart attack or stroke as the group taking a placebo. For patients taking 800 milligrams a day, the risk of serious cardiovascular events was 3.4 times as great.
National Institutes of Health Director Elias A. Zerhouni said that the agency is now reviewing about 40 other studies using Celebrex to determine whether they should be discontinued.
The announcement that Celebrex may pose serious risks similar to those of Vioxx quickly led to a new round of calls for reform at the FDA, which has come under heavy criticism for its oversight of prescription drug safety in recent months. Sen. Charles E. Grassley (R-Iowa), who has been especially critical, called for creation of an independent blue-ribbon review similar to the commission that studied the Sept. 11, 2001, attacks to recommend reforms.
"Right now, we have a situation where the public is left wondering when the next shoe might drop when it comes to drug safety," Grassley said in a statement.
"The Food and Drug Administration has earned a good reputation with decades of good work," he said. "But serious mistakes have taken place and lives may have been risked and lost. By having scientific experts scrutinize what's happened and make well-informed recommendations, both the executive branch and Congress could make reforms and strengthen public confidence in prescription drugs and the agencies that regulate those drugs."