The U.S. Food and Drug Administration failed the public in its oversight of Merck & Co Inc.‘s painkiller Vioxx, which has been withdrawn, and is “incapable of protecting America” from another dangerous drug, an agency researcher told Congress on Thursday.

David Graham, an FDA reviewer who had warned about the heart risks of Vioxx, called the FDA’s actions “a profound regulatory failure.”

Concerns about a possible link between Vioxx and serious heart problems were building during the drug’s more than four years on the market.

The FDA required a warning about the heart risk but felt the drug’s benefits made it worth keeping on the market.

Merck withdrew Vioxx on Sept. 30 after a study showed the drug doubled heart attack and stroke risk.

“I would argue the FDA as currently configured is incapable of protecting America against another Vioxx. We are virtually defenseless,” Graham told the Senate Finance Committee.

Committee Chairman Charles Grassley, an Iowa Republican, said he was concerned the FDA had a “far too cozy” relationship with drug companies and suggested an independent office of drug safety might be needed.

Sandra Kweder, deputy director of the FDA’s Office of New Drugs, said the agency “worked actively and vigorously with Merck to inform public health professionals of what was known regarding (cardiovascular risk) with Vioxx and to pursue further definitive investigations.”

Graham told the committee he felt pressured by supervisors to water down his findings from a study of patient insurance records that Vioxx users had a 50 percent greater chance of heart attacks and sudden cardiac deaths than people who took Pfizer Inc.‘s rival medicine Celebrex.

In a statement Wednesday, Acting FDA Commissioner Lester Crawford said Graham had violated long-standing procedures for publishing scientific findings when he submitted his research to a medical journal without FDA clearance.

Grassley said Crawford’s statement appeared intended to intimidate a witness on the eve of a hearing.

Utah Republican Sen. Orrin Hatch cautioned fellow senators to keep an open mind, saying: “Today some are trying to punish one drug company for acting appropriately within the framework of our regulatory system.”

But Grassley said Vioxx was the second example this year of the FDA not having proper respect for it own scientists. Another FDA reviewer, Dr. Andrew Mosholder, had warned antidepressants were linked to suicidal behavior in pediatric patients, but supervisors initially kept him from making those views public.

“Now we have scientists in this particular (Vioxx) case who are being harassed within the agency because of sticking to their own science,” Grassley said.

Grassley also faulted Merck for aggressively marketing Vioxx for nearly two years between submitting results of a trial to the FDA in June of 2000 showing a higher incidence of cardiac problems with Vioxx and the FDA approving a new label detailing those risks in April 2002.

“A blockbuster drug became a blockbuster disaster,” Grassley said.

Merck Chief Executive Raymond Gilmartin, in written comments, said the company followed “a rigorous scientific process at every step of the way with Vioxx.”

“Over the past six years, we have promptly disclosed results of numerous Merck-sponsored studies to the FDA, physicians, the scientific community and the media,” Gilmartin said.