GlaxoSmithKline’s Avandia is once again making the headlines after it was revealed that the peer reviewer looking at the now-notorious meta-analysis on the diabetes drug’s safety profile leaked a confidential copy of the article to the firm before it was published in the New England Journal of Medicine.

Details of this strange turn of events were about to be published in the journal Nature before US Senator Charles Grassley broke its embargo and issued a letter written to GSK asking the firm what action it had taken on receiving the article from Steven Haffner of the University of Texas Health Science Center in San Antonio. The NEJM piece linked Avandia (rosiglitazone) to a 43% increased risk in heart attacks and strokes and observers were struck by the speed and detail of GSK’s rebuttal. There would now appear to be an explanation, however.

The Nature article notes that Dr Haffner faxed his copy of the article 17 days before publication in the NEJM to Alexander Cobitz, a GSK employee he knew. “Why I sent it is a mystery,” Dr Haffner is quoted as saying. “I don’t really understand it. I wasn’t feeling well. It was bad judgement.” He notes that he has worked with the UK-based drugs giant many times, principally on the Avandia ADOPT study, but refutes the notion that his motivastion for the leak was cash. “I’ve got a considerable amount of money,” he said. “I didn’t do it to raise my income or anything like that.”

GSK spokeswoman Nancy Pekarek told Nature that she was not aware of anyone at the firm informing the journal of the confidentiality breach. She added that Dr Haffner had expressed concerns regarding the methodology of the analysis, and sent the article, written by Steven Nissen of the Cleveland Clinic, for advice.

Dr Nissen has expressed his disappointment over the confidentiality breach, as has Sen Grassley, a fierce critic of the relationship of the pharmaceutical industry with doctors and regulators. He said that “the most troubling aspect of this situation is that the integrity of another aspect of the scientific process is called into question - scientific peer review”.