Suspicions that the arthritis drug Vioxx could cause serious cardiovascular damage arose as early as 1999, the year Vioxx was approved by the Food and Drug Administration as a next-generation remedy that might be safer than older drugs like ibuprofen.
The fact that Vioxx remained on the market for five years, and grew into a $2.5 billion blockbuster before it was abruptly withdrawn by Merck & Co. on Thursday over safety concerns, points up inadequacies in the rules and resources wielded by the FDA, some critics say.
“I wish the FDA would have looked at it and said, ‘The pharmacology clearly shows there could be a problem,’ ” said David Miceli, the leader of a nationwide group of trial lawyers who have filed suits on behalf of patients who claim they were injured by Vioxx.
Miceli said the FDA is woefully understaffed. And its guidelines often lead it to look only at the evidence presented by drug manufacturers, he said not at the further data that could have been generated.
In the end, it was a study done voluntarily by Merck not research required by FDA that settled troubling safety questions that have surrounded Vioxx for years. And that research was not intended to root out cardiovascular risks. It was designed to further expand the Vioxx market by proving its value for a new class of customers, cancer patients.
Instead, the new Merck study definitively showed that Vioxx boosted the risk of heart attacks and strokes. After consulting with FDA, Merck voluntarily pulled the product. The withdrawal not only doomed one of Merck’s biggest sellers but also called into question the safety of similar drugs like Pfizer Inc.’s blockbuster Celebrex, an anti-inflammatory and pain drug approved by the FDA in 1998.
FDA Acting Commissioner Dr. Lester Crawford said FDA will closely monitor other drugs in the same class as Vioxx for similar side effects.
Pfizer said Celebrex remains an appropriate treatment for osteoarthritis, rheumatoid arthritis and acute pain.
“Pfizer is confident in the long-term cardiovascular safety of Celebrex, ” said Dr. Joe Feczko, Pfizer’s president of worldwide development.
Merck’s study confirms the fears first raised in 1999 by Dr. Garret FitzGerald, chairman of the University of Pennsylvania pharmacology department.
At the time that Vioxx and Celebrex were approved, the new class of drugs, known as COX-2 inhibitors, were being touted as anti-inflammatory agents that would cause less gastrointestinal damage than standby drugs like aspirin or ibuprofen.
But even back then, FitzGerald and his colleagues were warning that the drugs could actually interfere with bodily mechanisms that protect the heart and blood vessels.
FitzGerald said the newest Merck study tracks precisely with his theory, and with his published research after 1999 that supports it.
“Merck behaved very ethically today,” said FitzGerald, who has acted as a consultant to Merck, Pfizer and other drug companies. “The spotlight now is on Pfizer and the FDA.”
He said FDA should now take a closer look at all studies on Celebrex and other COX-2 inhibitors to determine whether they also raise the danger of heart disease and stroke.
When the FDA issued its original approval for Vioxx, the studies submitted by Merck were not designed to pick up cardiovascular events, even though the risks were apparent to FitzGerald and other researchers, said Miceli. A post-approval study by Merck strongly indicated an increased risk of heart attacks in 2000, but the company was able to argue that the data were not conclusive because, again, the study was not designed to answer that question. The FDA strengthened warnings on the drug’s label, but allowed it to stay on the market.
In data collected by the FDA since Vioxx’s introduction , the drug tops FDA’s list for the number of serious side effects reported to the agency, said John Lehmann, who has a Ph.D. in pharmacology and runs a consumer watchdog site called DrugIntel.
Sidney Wolfe, director of Public Citizen’s Health Research Group, faulted both Merck and the FDA for Vioxx’s long stay on the market.
“This family of drugs, the COX-2 inhibitors, once referred to as ‘super aspirins,’ are turning out to be more like super disasters,” Wolfe said.