The results of nearly 30 percent of clinical trials are not publicly disclosed within four years of completion, according to a study appearing in PLOS One.
Hiroki Saito from Carney Hospital in Massachusetts and Boston University's Christopher Gill analyzed some 400 randomly selected trials from the ClinicalTrials.gov database that were listed as being complete and calculated the time from them being finished to their publication.
Of the approximately 70 percent of studies that were publicly disclosed, the mean time to that disclosure was 647 days. Earlier stage studies and those with industry funding, Saito and Gill note, were less likely to be reported.
“Phase II is really where all the science takes place in clinical development. … The fact that not even half of industry-sponsored Phase II trials ever see the light of day is profoundly depressing," Gill tells Ed Silverman at Pharmalot. "What it means is that, in effect, the majority of scientific discovery from industry is not being published."
And as Silverman notes, those late stage trials that are be published were likely successful in earlier stages as well, so only "success stories" are being submitted for publication. He adds, though, that journals may be less likely to publish early stage studies.