A double-blind, placebo-controlled randomised trial conducted in Russia found that slow-release naltrexone implants resulted in better HIV treatment outcomes for people living with HIV and opioid dependence when compared to orally administered naltrexone. This research was carried out by Professor Evgeny Krupisky and colleagues at the First Pavlov State Medical University of St Petersburg, along with colleagues at the University of Pennsylvania, and was published in the April issue of The Lancet HIV.
Naltrexone is a drug that blocks the effects of opioids, with implants providing opioid-blocking effects for up to three months. However, in most countries the only licensed form of naltrexone is oral tablets or intramuscular injections; the oral dose only blocks the effects of opioids for 24 hours and needs to be taken daily while the injection has effects for up to a month. Currently, Russia is the only country where a regulatory agency has approved the use of a naltrexone implant.
At 48 weeks, people with naltrexone implants had completed more weeks of antiretroviral therapy (ART) and were more likely to be virally suppressed (66% vs 50%) than those taking oral naltrexone doses. The longer opioid effects were blocked, the more protection individuals received from missed ART doses and impulsive behaviours related to their addiction. The researchers concluded: “The higher proportion of relapse-free weeks and weeks in HIV treatment among participants with naltrexone implants than in participants taking oral naltrexone is the most likely contributor to better outcomes.”
Nearly 40% of all new HIV infections in eastern Europe are as a result of injecting drug use, with Russia accounting for three-quarters of all new infections in the region. Untreated opioid addiction is linked to poor ART adherence and outcomes in HIV-positive people. Methods used to manage opioid addiction elsewhere, such as opioid substitution therapy with methadone, are illegal in Russia. However, the naltrexone implant which provides slow-release naltrexone for up to three months is available in Russia. The authors wanted to investigate if this implant would offer superior outcomes in people living with HIV when compared to naltrexone taken orally.