Updated from 1:47 p.m. ESTA veteran researcher for the Food and Drug Administration told legislators Thursday that the recent withdrawal of Vioxx by Merck ( MRK) represents "a profound regulatory failure" that could easily be repeated with other drugs." The scientist, David J. Graham, who was the lead author in a study criticizing Vioxx, said he was pressured by senior management to alter his conclusions that Vioxx represented a greater cardiovascular risk than Celebrex, a similar arthritis treatment and pain reliever made by Pfizer ( PFE). Graham was the first witness in a hearing held by the Senate Finance Committee, which is investigating the Vioxx case as well as the FDA's drug approval and drug safety review efforts. The last witness of the day was Raymond V. Gilmartin, chairman and CEO of Merck, who said the company acted quickly and responsibly once carefully designed medical research showed that Vioxx presented a greater risk of heart attack and strokes among people who used the drug for more than 18 months. If the trial had ended at 18 months, he noted, there would have been no statistically significant difference in risk between patients who took Vioxx and patients who received a placebo. Graham said the FDA is "incapable of protecting America against another Vioxx" because of bureaucratic torpor and calcified policies. Graham noted that during his FDA career, he has recommended that 12 drugs be pulled from the market, adding that only two remain on the market. Calling Vioxx "a national disaster" and arguing that the drug should have been removed from the market as far back as four years ago, Graham directed most of his anger at the FDA. He said the agency creates a bureaucratic culture in which "post-marketing safety is an afterthought."