By Melissa Davis
The makers of some blockbuster painkillers could be nursing some wounds of their own. David Graham, a maverick drug safety expert at the Food and Drug Administration, has once again taken swings at so-called Cox-2 inhibitors. In testimony during a special hearing on Thursday, Graham highlighted new risks — and questioned the real value — of popular painkillers that have generated billions of dollars for the likes of Merck and Pfizer.
“There really doesn’t appear to be a need for Cox-2” drugs, Graham concluded.
Graham first scored headlines late last year for criticizing his own agency’s ability to protect the public from drugs like Vioxx. Merck withdrew the wildly popular drug in September because of heart risks that critics, including Graham, believe were evident for some time. Pfizer continues to market its own Cox-2 inhibitors, Bextra and Celebrex. Both companies have defended their actions regarding the drugs.
But Graham has suggested that the entire class poses unacceptable risks. “This is my opinion, not the FDA’s,” Graham repeatedly stressed. “I believe, based on the evidence, that there is a Cox-2 effect [on the heart] and that the Cox-2 effect is dose-dependent.”
Graham went on to single out one difference between Vioxx and similar drugs that remain on the market. He said, quite simply, that “a safe dose for [Vioxx] wasn’t identified” in various studies.
Graham also challenged claims made by Merck both before and after the company pulled Vioxx off the market. A study conducted several years ago showed that patients were far more likely to suffer from heart problems if they used Vioxx instead of naproxen, a drug popularly known as Aleve. Yet Merck attributed the difference not to heart ailments caused by Vioxx but instead to cardiac protection offered by naproxen.
Graham essentially said that one would have to believe that naproxen was the best heart protector “in the history of mankind” to buy that argument. Then he went a step further and questioned studies that showed naproxen offered cardiac benefits in the first place. He said the most well-known study, which found that naproxen reduced certain heart problems by 16%, included patients who had used the drug at any time in the previous six months and not necessarily on a regular basis. He therefore questioned the connections that were drawn not only from that study but in three others as well.
“None of them provides credible evidence of a protective effect,” he declared, adding bluntly, “Naproxen is not cardio-protective.” Moreover, Graham went on to say that Vioxx can cause immediate harm. Merck has said that it identified cardiac risks in patients only after they used the drugs for 18 months. But Graham countered that argument with the results of multiple studies that uncovered heart problems within months or even days. He highlighted his own study in particular.
Some “50% of our [cardiac] cases occurred within two to three months of starting the drug,” he said.
And “nobody in our study was on it for more than 15 months.”
Graham painted a startling picture of the damage that Vioxx may have caused. He said that most other drugs have been withdrawn from the market because they triggered acute liver failure in one patient in 1 million, or “the rate of being struck by lightning.” In contrast, he said, Vioxx increased the risk of heart attacks — which occur in one of every 50 older males — by five times and, therefore, put a huge number of people in danger.
Thus, he said, there is “no comparison” between the problems caused by previously withdrawn drugs and those triggered by Vioxx.
Graham’s testimony eventually led to broader questions about the FDA’s approval of drugs in general. One panelist questioned why longer trials — which could better identify risks — did not precede the approval of drugs like Vioxx.
Both Merck and Pfizer took advantage of FDA’s “fast-track” approval process when rushing their Cox-2 inhibitors onto the market. They have since attracted criticism for using an avenue originally meant for the treatment of life-threatening conditions, such as AIDS and cancer, and unnecessarily putting consumers at risk in the process. Cox-2 inhibitors have been shown to effectively relieve chronic pain, but alternatives have long been available for patients who can stomach them.
Graham said the agency’s approval of drugs prior to lengthy studies raised “a legitimate question.” He also attempted to explain why more long-term studies are not done. “I think that they’re incredibly expensive,” he said. “Companies don’t want to do them; there’s not an incentive to do them. … [And] the fact is they’re not requiring them.”
Shares of both Merck and Pfizer continued to fall during the second day of the three-day hearing. Merck took the bigger hit, sliding 43 cents to $28.59. Pfizer dropped 15 cents to $24.80.
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