Reboxetine is one example. It's an antidepressant pushed by Pfizer. Initial studies showed it was effective versus placebo or SSRIs, but later research found serious publication bias -- Pfizer suppressed evidence suggesting it was not effective. Only after the German Institute for Quality and Efficiency in Health Care obtained unpublished data from Prizer was its lack of efficacy obvious:

http://www.bmj.com/content/341/bmj.c4737

Pre-registration and mandatory publication would help prevent this.