Opioid use disorder continues to be a significant problem in the United States and worldwide. Three medications-methadone, buprenorphine, and extended-release injectable naltrexone,- are efficacious for treating opioid use disorder (OUD). However, the utility of these medications is limited, in part due to poor rates of retention in treatment. In addition, minimum recovery milestones and other factors that influence when and whether individuals can safely discontinue medications are unknown. The National Drug Abuse Treatment Clinical Trials Network (CTN) study "Optimizing Retention, Duration, and Discontinuation Strategies for Opioid Use Disorder Pharmacotherapy" (RDD; CTN-0100) will be among the largest clinical trials on treatment of OUD yet conducted, consisting of two phases, the Retention phase, and the Duration-Discontinuation phase. The Retention phase, open to patients initiating treatment, will test different doses and formulations of buprenorphine (standard dose sublingual, high dose sublingual, or extended-release injection), and a digital therapeutic app delivering contingency management and cognitive behavioral counseling on the primary outcome of retention in treatment. The Discontinuation phase, open to patients in stable remission from OUD and choosing to discontinue medication (including participants from the Retention phase or from the population of patients treated at the clinical site, referred by an outside prescriber or self-referred) will study different tapering strategies for buprenorphine (sublingual taper vs taper with injection buprenorphine), and a digital therapeutic app which provides resources to promote recovery, on the primary outcome of relapse-free discontinuation of medication. This paper describes how the RDD trial derives from two decades of research in the CTN. Initial trials (CTN-0001; CTN-0002; CTN-0003) focused on opioid detoxification, showing buprenorphine-naloxone was effective for detoxification, but that acute detoxification did not appear to be an effective treatment strategy. Trials on comparative effectiveness of medications for opioid use disorder (MOUD) (CTN-0027; CTN-0030; and CTN-0051) highlighted the problem of dropout from treatment and few trials defined retention on MOUD as the primary outcome. Long-term follow-up studies on those patient samples demonstrated the importance of long-term continuation of medication for many patients to sustain remission. Overall, these trials highlight the potential of a stable research infrastructure such as CTN to advance treatment effectiveness through a programmatic succession of large clinical trials.