It’s hard to gain access to unpublished data and reports for trials you don’t know even exist. So the first step is learning of a trial’s existence. Published trials are often easy to find, but no so for unpublished trials. There’s no simple or quick process to find an exhaustive list of every unpublished trial conducted with a given drug, but with a little effort you may be able to at least begin identifying some unpublished trials. We suggest three approaches:

  1. Regulatory reports: Look for the list/table of studies that appear in easily accessible regulatory reports.  The best sources are FDA medical and statistical officer reports and EMA EPARs. FDA medical and statistical officer reports often contain a “Table of Clinical Studies” and EPARs generally discuss trials in the section of the EPAR on “Pharmacological Properties” – but search around these documents.  Find FDA reports via the Drugs@FDA database and EPARs can be found on EMA’s website.  We have some background info about all of these resources on our Regulatory Resources and glossary pages. In particular, see glossary entries on medical officer reviews, statistical officer reviews, EPARs, and SmPCs for a sense of what each of these documents look like before you jump in.
  2. Trial registries: Search trial registers such as ClinicalTrials.gov or ICTRP. Trial registers were established in part with the explicit purpose of trying to decrease the number of stealth trials i.e. trials for which one doesn’t even know of their existence. In addition, some sponsors maintain their own registers (e.g. Merck and GSK) or are members of consortiums (e.g. ClinicalStudyDataRequest.com) where clinical trial information is posted. Searching these sources by drug may help identify some unpublished trials.
  3. Other: If the medical product you’re interested in has been involved in litigation, you may also want to check the Drug Industry Documents Archive to see what kinds of documents might be in that repository.