There are several ethical, regulatory, and logistical challenges to conducting long-term placebo-controlled, double-blind randomized controlled trials (RCTs). Because of this, the majority of contemporary phase III trials on opioid efficacy and safety do not last longer than three months.
In light of this, open-label studies are particularly valuable, as they are often of longer duration and “reflect patient experience before and after long-term opioid therapy,” according to the authors of a poster presented at the American Pain Society’s 32nd Annual Scientific Meeting, held May 8-13, 2013, in New Orleans, LA.
In “Long-term Efficacy and Safety of Opioid Therapy for Chronic Non-cancer Pain: Evidence from Randomized and Open-label Studies,” Matsuno, Wallace, Glanzman, et al, analyzed data from published RCTs and open-label studies that had a duration of six months or longer to learn more about the long-term efficacy and safety of opioid therapy for patients with chronic non-cancer pain.
They conducted a literature search of major databases to identify RCTs, single-arm open-label trials, and open-label extension studies following an RCT that were six months or more in duration. They also searched clinical guidelines, consensus statements, and other sources to identify additional articles.