What is PLoS Medicine’s policy on trials registration? | Speaking of Medicine

"It’s now well over five years since the International Committee of Medical Journal Editors announced a policy requiring that clinical trials considered for publication in its journals must have been previously registered in a public database. This policy was originally intended to promote greater transparency in clinical trials research, prevent the suppression of trials with “negative” results, and prevent duplication of research. However, PLoS journals still receive many submissions a month reporting results of unregistered trials. So, here’s a quick update of our policy in this area: ...All trials should be registered before enrollment of the first participant. However, we do apply exceptions for very old trials that were started before 1 July 2005...."