When Merck pulled its blockbuster painkiller, Vioxx, from the market on Celebrex and Bextra, Prexige, which is manufactured by Novartis, and Sept. 30, 2004, after a large clinical trial provided evidence that the drug increased the risk of heart attack and stroke, the move cast doubts on the safety of similar Cox-2-specific inhibitors, including Pfizer's another Merck drug, Arcoxia. In February, a panel of experts advising the US Food and Drug Administration aired those doubts, but voted against banning Celebrex, Bextra, or Vioxx. Regardless, some scientists worry that the shadow of risk could hamper future research on the entire class. "In light of the Vioxx withdrawal and the public outcry, I expect there will be fewer dollars available to do the research that we need to do to find out how these – and other – drugs work," says Matt Breyer, professor of medicine at Vanderbilt University, adding that Vioxx's cancer-prevention and disease-fighting benefits should continue to be researched.