The company and outside scientists are now doing further studies to see if it is possible to better predict which patients would benefit from the drug.

The rule would apply only to outside scientists doing clinical research, not to employees of the drug companies.

Some outside scientists question whether a treatment that starts after the toxin is already in the bloodstream would be effective.

The institutes' staff began the preliminary inquiry last year and the panel of outside scientists was appointed to review the evidence.

Merck promoted Vioxx heavily despite years of concern from outside scientists and its own researchers about the drug's risk.

The four outside scientists reviewing the fusion effort were appointed by the council and are to issue a report by December.

But outside scientists have raised many questions about the research.

And Hartwig himself had been nervous enough to call in an outside environmental scientist.

Amgen executives, and some outside scientists, say it is still far from clear if the drugs are truly dangerous.

In their letter yesterday, the outside scientists strongly disagreed.