The pharmaceutical industry has previously been accused of failing to submit all clinical trials data for publication, particularly if the results are unfavourable for the drugs in question. However, a recent study published in the British Medical Journal found no evidence of submission or publication bias.
Evoniuk and co-workers, who are employees or past employees of GlaxoSmithKline (GSK), compiled a list of all human drug studies completed by GSK over a 6-year period (2009 to 2015), and noted whether the results of each study had been submitted to a peer-reviewed journal. Individuals blind to the submission/publication status of the trials then rated them as either ‘positive’ (favourable for the study drug), ‘negative’ (perceived to be unfavourable for the study drug), ‘mixed’, or ‘non-comparative’.
Of the 1064 trials identified, 904 (85%) had been submitted as a full manuscript by the study cut-off date of February 2016, and a further 77 (7%) had been written up as conference abstracts. Studies with positive outcomes were less likely to have been submitted for publication than studies with negative outcomes (79% versus 92%). While the rate of acceptance at first submission was slightly higher for studies with positive outcomes (56% versus 48%), overall publication rates by the cut-off date were higher for studies with negative outcomes (77% versus 66%).
This study examined data from only a single pharmaceutical company. Nevertheless, the authors argue that the results ‘provide a clear signal that submission and publication bias against studies with negative outcomes might be less widespread than has generally been assumed and should not deter efforts to publish them’.