Extended-Release Naltrexone vs. Buprenorphine for Opioid Treatment

For opioid-dependent patients in the U.S. and most of the rest of the world, detoxification or detoxification followed by short term residential treatment, with the goal of achieving long-term abstinence from opioid misuse is a mainstay of treatment. Nonetheless, the majority of patients treated in this way will relapse to opioid misuse, leading to a costly and ineffectual cycle of readmission for repeated detoxifications. The overarching goal of CTN-0051 is to foster adoption of new relapse-prevention pharmacotherapies in community-based treatment programs (CTPs) where these could have a substantial public health impact. To this end CTN-0051 assesses the comparative effectiveness of extended release injectable naltrexone (XR-NTX, Vivitrol®), an opioid antagonist recently approved and indicated for the prevention of relapse to opioid dependence, versus buprenorphine-naloxone (BUP-NX, Suboxone®), a high affinity partial agonist indicated for maintenance treatment of opioid dependence, as pharmacotherapeutic aids to recovery. The study is conducted in 8 CTN-affiliated CTPs that provide or partner with detoxification services (inpatient/residential) which have the capacity to maintain participants opioid-free for approximately 3-7 days, have the capacity to provide medication-assisted therapy, and can provide a minimum of one group or individual counseling session per week during the 24-week treatment period. Up to 600 eligible participants will be randomized to treatment with XR-NTX or BUP-NX for 24 weeks (sufficient to include 350 participants who are randomized more than 72 hours after their last opioid). To maximize generalizability, the point of randomization is flexible, from shortly after program admission until just prior to program discharge. A data analysis modification (assessment of whether the early vs. late randomizers have a differential treatment effect and if so, time to relapse will be estimated for early and late randomizers separately) will occur if differential treatment initiation is a problem for cases randomized prior to completing detoxification (i.e., significantly fewer early randomizers are able to complete detoxification and XR-NTX induction). The primary goal of the study is to estimate the difference, if one exists, between XR-NTX and BUP-NX in the distribution of the time to relapse (i.e., loss of persistent abstinence) during the 6-month trial. The primary outcome measure will be the time to the event, with the event called relapse. Secondary objectives are to: (1) compare outcome on XR-NTX versus BUP-NX across a range of clinical safety and secondary efficacy domains, and (2) explore demographic and, clinical, and genetic predictors of successful treatment and moderators of differential effectiveness (i.e., what variables may help clinicians choose which of these treatments is best for a given patient), and (3) collect a limited dataset to permit analyses of economic costs and benefits of the two treatments. Toward the end of the 24-week treatment period, participants are referred for follow-up care in the community (which could include pharmacotherapy if desired and available), and follow-up outcomes are assessed at week 28 and week 36 after randomization. For participants receiving BUP-NX, who do not wish to continue, or for whom community resources are not available, the study provides a two-week BUP-NX taper. In an ancillary genetics study we plan to study functional variants in three genes (OPRM1, OPRK1 and PDYN), known to affect the dynamic response to opioid receptor ligands. These variants will be evaluated in CTN-0051 for their contribution to treatment retention, abstinence, and depression. Blood collection for DNA extraction will occur at the same time that blood is collected for medical safety and liver function evaluation, precluding the need for an additional needle-stick. Coded blood samples for the genetics studies will be sent to the NIDA Center for Genetics Repository.