Are Vioxx and Celebrex ‘Wonder’ Drugs?
While the arthritis drugs Vioxx and Celebrex have produced sales in the billions since their respective launches in 1999, it is still inconclusive whether these "wonder" drugs are any safer than over-the-counter pain relief drugs, and the FDA is concerned that they may put patients at risk of unforseen side effects, USA Today reports. The FDA's Arthritis Advisory Committee will hold a hearing this week in which Merck & Co., which manufactures Vioxx, and Pfizer Inc. and Pharmacia Inc., which jointly produce Celebrex, will request that they be allowed to change the drugs' label to indicate that the medications pose less risk of gastrointestinal problems than other non-steroidal anti-inflammatory drugs (NSAIDs), such as aspirin and ibuprofen. The marketing campaigns of Vioxx and Celebrex have led many doctors and patients to this conclusion, USA Today reports, but "so far, their manufacturers, have not been allowed to make that claim in their" advertisements. The drug makers' arguments center around two enzymes, Cox-1 and Cox-2. While all NSAIDs inhibit the production of Cox-2, which is "involved in pain and inflammation," Celebrex and Vioxx are thought to be the first to not inhibit Cox-1, which "helps keep the stomach lining intact." The FDA's decision about the labeling could translate into millions more in revenue for the drugs' manufacturers. Hemant Shah, an industry analyst, estimates that the prescription NSAID market could grow 40% to 50%. "You're talking about a massive impact on the way these products are going to be used based on what the FDA advisory panel decides," he said.
Many doctors and health plans, however, hold safety and cost control concerns about a labeling change. Celebrex and Vioxx cost roughly 20 times more than ibuprofren, and insurers believe that a labeling change would encourage even more physicians to prescribe the drug. In addition, a "boost in the drug's safety profile could trigger prescriptions for higher, untested doses." Despite evidence in clinical trials that Vioxx and Celebrex do not cause stomach problems as often as other NSAIDS, the FDA required the drug manufacturers to conduct further tests to prove that the drugs would "actually prevent gastrointestinal complications that would require medical care." While both trials showed that Vioxx and Celebrex users experienced fewer stomach complications, many patients who participated in the Celebrex study also took aspirin to ward off heart attacks, which "apparently" cancelled out any benefits that were gained by taking Celebrex. And in the trial for Vioxx, which was compared to the NSAID Naproxen (brand name Aleve) instead of aspirin, Vioxx users were more likely to have heart attacks. According to Allan Korn, senor vice president for clinical affairs and chief medical officer at the Blue Cross and Blue Shield Association, there are several "real-world" activities which may eliminate any potential benefit that Vioxx and Celebrex offer in a vacuum. "There are an awful lot of patients who are taking these drugs who take aspirin every day, have a cocktail or wine frequently -- all of which are far more irritating than ibuprofen," he said.
At its meeting this week, the FDA committee will also question whether Vioxx and Celebrex have dangerous side effects. FDA official Robert DeLap said, "People have a lot of organ systems. One does not know if a drug that produces less of a certain side effect in the gastrointestinal system might produce other adverse effects." USA Today reports that rheumatologists have "raised concerns" about a greater risk of "blood pressure elevation and fluid retention, or edema" in patients who take "higher doses of Vioxx," which could lead to congestive heart failure in "vulnerable patients." Merck senior vice president for clinical research Eve Slater said that "perhaps one out of every 100,000 Cox-2 inhibitor candidates would do better on Celebrex than Vioxx because of edema," almostthe same number "who might develop a rash from taking Celebrex" (Rubin, USA Today, 2/6).This is part of the California Healthline Daily Edition, a summary of health policy coverage from major news organizations. Sign up for an email subscription.