Sublocade: Why a placebo arm?

In a time when people are dying from illicit fentanyl overdoses, why would a trial for a new medication to treat opioid use disorder — a formulation of buprenorphine, already proven to be safe and effective in oral form — include a placebo arm? This was the question asked by many when the results of Indivior's trial for Sublocade, a buprenorphine injection that lasts a month, were published last month in The Lancet (see ADAW , Feb. 25). The trial results were what led to Sublocade's approval by the Food and Drug Administration (FDA) for the treatment of opioid use disorder more than a year ago (see ADAW , Dec. 11, 2017).