An implant that provides naltrexone, the medication-assisted treatment for opioid use disorder (OUD), over a three-month period, was associated with improved HIV-related health outcomes compared with the daily oral version of the drug in a recent study conducted in Russia.


The three-month naltrexone implant is approved in Russia but not in the United States. The Food and Drug Administration has only approved an extended-release injectable version of naltrexone that must be given monthly and the daily oral drug. However, unlike in the United States, Russia has not approved the two other forms of MAT, methadone and buprenorphine.


Publishing their findings in The Lancet HIV, researchers recruited 200 participants in Saint Petersburg and the surrounding Leningrad region between July 2011 and April 2014 into a 48-week, double-blind, double-dummy, placebo-controlled Phase III randomized trial. The participants were all HIV positive, had a viral load above 1,000, had not taken antiretroviral (ARV) treatment for at least a year prior and were seeking treatment for OUD.


The participants were evenly randomized into two groups of 100 to receive either the three-month naltrexone implant and a daily oral placebo or a placebo implant and daily oral naltrexone. All were offered biweekly drug counseling and ARV treatment.


At week 24 of the study, 38 percent of the implant group and 35 percent of the oral group had a viral load below 400. By week 48, a respective 66 percent and 50 percent of the participants in each group had a viral load below that threshold. This meant that the implant was associated with a 1.32-fold increased likelihood of having a suppressed viral load compared with the oral drug.  


The study saw seven serious adverse health events, including three deaths in the implant group (due to heart disease, trauma and AIDS-related complications, respectively) and four in the oral group (due to overdose in one case, pancreatic cancer in another and AIDS-related complications in another). Those who overdosed did so nine to 10 months after their last dose of oral naltrexone.


Those in the implant group remained in treatment for OUD for a median of 32 weeks without relapsing, compared with 20 weeks in the oral naltrexone group.


The longer the blockade of opioid effects, the more protection an individual gets from missed [ARV treatment] doses and impulsive behaviors that lead to relapse and poor, even fatal, outcomes,” the study authors concluded. “Commercial development of implants could result in a meaningful addition to addiction treatment options.”


To read a press release about the study, click here.


To read the study abstract, click here.