At least four members of a key committee advising the US Food and Drug Administration on the safety of a top selling drug have had financial ties to its manufacturers, raising questions about the rigor with which the agency minimises potential conflicts of interest.

Court documents reviewed by the BMJ and Washington Monthly show that at least four advisers conducted research for Bayer AG or other manufacturers or licensees of drospirenone, the synthetic progestogen contained in several oral contraceptive pills whose safety was under review. Another adviser agreed to conduct research for the company but never did. The advisers served as paid key opinion leaders, researchers, consultants, or speakers for Bayer and other manufacturers of drospirenone.

Each of the advisers with ties to manufacturers told the BMJ that they fully disclosed their ties to the FDA, although the FDA declined to release advisers’ financial conflict of interest forms, saying that they are “confidential” and cannot be shared.

There is no reason to that think the advisers did not make the requisite disclosures. However, when asked whether the agency was aware of any financial ties between its advisers and manufacturers or distributors of drospirenone, the FDA spokeswoman Morgan Liscinsky said, “No waivers were issued.” Waivers can be issued to …