CBS News Correspondent Sharyl Attkisson reports Dr. Robert Misbin, who led the FDA review of Rezulin, was summoned by FDA Internal Affairs for questioning about "the possible inappropriate release of information."
When he asked to bring a witness to the hearing, Misbin received an e-mail response from a superior that read: "...You are not permitted a witness. You will be asked oral questions. If you refuse...I will perceive this as non-cooperation and report such to your supervisor for disciplinary actions."
Misbin has refused to be questioned and has now been excluded from high level talks about Rezulin's safety with the FDA commissioner, even though he's the drug's chief medical reviewer.
The FDA wouldn't comment on any of this Friday, but has said in the past that its review of Rezulin is "ongoing."
Last week, CBS News reported that Misbin wrote Congressman Henry Waxman, D.-Calif., to complain, "I have been frustrated in my efforts to convince my superiors that the time has come to remove Rezulin from the market."
Rezulin is a drug used with insulin or other medications to control Type 2 diabetes. It has been linked to 58 deaths.
After CBS News reported a clinical researcher's claim that the drug's manufacturer, Warner Lambert, had pressured her to downplay problems that emerged during a Rezulin trial, Warner Lambert asked the FDA to conduct an "objective review" of the drug.
A second scientist who did research on the drug has also come forward alleging the drug maker pressured him to keep quiet about problems.
Warner-Lambert denies those charges and says it submitted all required data.
In a related development, Senator John Ashcroft, R-Mo., now has asked the FDA to begin an immediate investigation into Rezulin's safety and the allegation by the researchers who say Warner-Lambert misrepresented its dangers.