The study, conducted by Mayo Clinic professor of medicine Dr. Eric L. Matteson and colleagues, examined the association between tumor necrosis factor-alpha blockers (TNFs) -- used to treat rheumatoid arthritis -- and an increased risk of cancer and infections. Matteson's study found that certain TNFs, including Remicade, Enbrel and Humira, were linked to an increased risk of cancer -- particularly lymphoma -- as well as a higher risk of infection.
However, the researchers failed to alert JAMA editors that Abbot Laboratories, the maker of Humira, had been allowed to review the paper prior to publication. The researchers also failed to include a TNF drug made by Wyeth in their study, while the researchers were simultaneously working with the drug firm on a separate study. Finally, the Mayo researchers accepted $25,000 from Amagen, maker of Enbrel, for fellowship education training of one of the study's co-authors.
Matteson and his colleagues say the science behind their study is sound, and the omission of their conflicts of interest was an oversight.
"This was really a very embarrassing thing to me," Matteson said. "This occurred due to my inattention to our disclosure statement when we submitted our original paper. There were mistakes in the disclosure, not because I intended to mislead them, but simply because I was negligent."
Matteson says he informed JAMA editor-in-chief Dr. Catherine D. DeAngelis of the error a week prior to the study's publication on May 17, 2005. However, DeAngelis says she was first notified of the conflicts by one of the drug companies involved.
"It was very nice of [Matteson] to do it after the fact, since he knew we were about to initiate an investigation because someone let the cat out of the bag," DeAngelis said. "We are very serious about it. I don't like it when people don't fully disclose. I wanted this letter of apology."
In July, DeAngelis announced that JAMA had updated its conflict-of-interest disclosure policy to help "improve the transparency of reporting of potential conflicts of interest and to encourage more accurate and complete disclosures."