See here :http://www.trialsjournal.com/content/11/1/43 . An examination of trials of medication for stroke which were completed but never published.
This problem, the non-publication of trial data, does not seem to go away. I quote: “Well designed clinical trials should be published because their results can benefit patients, justifying the risk to trial participants from experimental treatments. We found 22 unpublished trials that reported the number of deaths. In these trials, 636 people died, but no information was available on whether the experimental drug had contributed to any of those deaths…..551 different researchers were involved in conducting these studies and of these, 72 had been involved in more than one trial that remained unpublished.”
So we lack the information about why the deaths in these trials occurred, despite the fact that the data exists. Good clinical trials are essential – but patients should refuse to take part unless they are given guarantees that publication of the results, no matter what they are, will follow promptly.