The phenomenon of "salami slicing" or "least publishable unit" is generally associated with academics and not commerce. One approaches the publication of a study that has yielded a certain amount of data not with the ideal mindset, "How could these data be reported in a way that most advances scientific knowledge?" but rather with, "How many publications can I generate from this given quantity of data?" The goal is generally the padding of one's CV.
The same technique, however, can be an effective tool for marketing drugs. If you do one study of a drug, and it results in six publications in six journals read by six different audiences, then you have spread the marketing message about the drug that much wider.
Glen Spielmans, Tracey Biehn, and Dustin Sawrey of the Department of Psychology, Metropolitan State University, St. Paul, MN, note that few studies have attempted to dissect salami slicing as it might pertain to pharmaceutical marketing. Thir review (subscription required) undertakes to analyze the phenomenon with regard to one drug, the antidepressant duloxetine (Cymbalta).
Their first finding was that a great number of pooled data analyses had been published, but that the vast majority were in one way or another a repackaging of only 8 controlled trials. Two of these 8 trials provided data for 33 pooled data analyses, and 6 of the 8 provided data used later in at least 20 pooled analyses.
The next finding had to do with redundancy in reporting data from the pooled analyses. For example, review of pooled data showed that it did not make any difference in either safety or efficacy if duloxetine was prescribed for men vs. women, African-American vs. caucasian, or Hispanic vs. non-Hispanic patients. One might have thought that a single published article would be sufficient to say that. Instead, three separate publications made those three comparisons.
None of this is any great surprise to those of us who have been following the drug-marketing and publication issues, nor is it news to find that the reviewers and editorial boards of medical journals appear to be easy pushovers for this sort of commercial marketing campaign. The present article, however, provides a finer-grained analysis of just how this can be accomplished and the extent to which the problem exists.
Spielmans GI, Biehn TL, Sawrey DL. A case study of salami slicing: pooled analyses of duloxetine for depression. Psychotherapy and Psychosomatics 79:97-106, 2010; e-pub 12/24/09