Injectable extended-release naltrexone for opioid dependence: a double-blind, placebo-controlled, multicentre randomised trial.

Krupitsky E, Nunes EV, Ling W, Illeperuma A, Gastfriend DR, Silverman BL.

Lancet. 2011 Apr 30;377(9776):1506-13. doi: 10.1016/S0140-6736(11)60358-9.

BACKGROUND: Opioid dependence is associated with low rates of treatment-seeking, poor adherence to treatment, frequent relapse, and major societal consequences. We aimed to assess the efficacy, safety, and patient-reported outcomes of an injectable, once monthly extended-release formulation of the opioid antagonist naltrexone (XR-NTX) for treatment of patients with opioid dependence after detoxification. METHODS: We did a double-blind, placebo-controlled, randomised, 24-week trial of patients with opioid dependence disorder. Patients aged 18 years or over who had 30 days or less of inpatient detoxification and 7 days or more off all opioids were enrolled at 13 clinical sites in Russia. We randomly assigned patients (1:1) to either 380 mg XR-NTX or placebo by an interactive voice response system, stratified by site and gender in a centralised, permuted-block method. Participants also received 12 biweekly counselling sessions. Participants, investigators, staff , and the sponsor were masked to treatment allocation. The primary endpoint was the response profile for confirmed abstinence during weeks 5-24, assessed by urine drug tests and self report of non-use. Secondary endpoints were self-reported opioid-free days, opioid craving scores, number of days of retention, and relapse to physiological opioid dependence. Analyses were by intention to treat. This trial is registered at, NCT00678418. FINDINGS: Between July 3, 2008, and Oct 5, 2009, 250 patients were randomly assigned to XR-NTX (n=126) or placebo (n=124). The median proportion of weeks of confirmed abstinence was 90.0% (95% CI 69.9-92.4) in the XR-NTX group compared with 35.0% (11.4-63.8) in the placebo group (p=0.0002). Patients in the XR-NTX group self-reported a median of 99.2% (range 89.1-99.4) opioid-free days compared with 60.4% (46.2-94.0) for the placebo group (p=0.0004). The mean change in craving was -10.1 (95% CI -12.3 to -7.8) in the XR-NTX group compared with 0.7 (-3.1 to 4.4) in the placebo group (p<0.0001). Median retention was over 168 days in the XR-NTX group compared with 96 days (95% CI 63-165) in the placebo group (p=0.0042). Naloxone challenge confirmed relapse to physiological opioid dependence in 17 patients in the placebo group compared with one in the XR-NTX group (p<0.0001). XR-NTX was well tolerated. Two patients in each group discontinued owing to adverse events. No XR-NTX-treated patients died, overdosed, or discontinued owing to severe adverse events. INTERPRETATION: XR-NTX represents a new treatment option that is distinct from opioid agonist maintenance treatment. XR-NTX in conjunction with psychosocial treatment might improve acceptance of opioid dependence pharmacotherapy and provide a useful treatment option for many patients. FUNDING: Alkermes.

PMID: 21529928

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.