Krupitsky 2019: naltrexone implant vs pills for people with HIV and opioid addiction

What they tested

In Saint Petersburg, Russia, and the surrounding region, 200 people with HIV who were addicted to opioids and starting antiretroviral therapy (ART, the medicines that control HIV) were randomly split into two groups of 100. One group got a slow-release naltrexone implant plus dummy pills; the other got naltrexone pills plus a dummy implant. Neither patients nor staff knew who had which.

The main measure was whether people's HIV viral load was below 400 copies per mL at 24 and 48 weeks, a sign that HIV treatment was working.

What they found

At 24 weeks, 38 people in the implant group and 35 (35%) in the oral group had viral loads under 400 copies per mL (risk ratio 1.1, p=0.77), no significant difference.

At 48 weeks, 66 in the implant group and 50 in the oral group were under that level (risk ratio 1.32, 95% CI 1.04-1.68; p=0.045).

There were seven serious adverse events. Three were deaths in the implant group (from heart disease, trauma and AIDS), and four were in the oral group (two overdoses, pancreatic cancer and AIDS). The overdose deaths happened 9-10 months after the last naltrexone dose.

Limits

• The main measure was HIV viral load, so the abstract says more about HIV treatment than about opioid relapse.
• The benefit showed up only at 48 weeks, not at 24, and the 48-week result was close to the usual cutoff for significance (p=0.045).
• Everyone was treated in Saint Petersburg or the Leningrad region, so the results may not carry over to other health systems.

What it means if you're considering naltrexone

For people with HIV and opioid use disorder, this trial suggests a longer-lasting form of naltrexone may help HIV treatment work better at 48 weeks than daily pills. The authors argue that longer opioid blockade gives more protection from missed HIV doses and impulsive relapse. It compared two forms of naltrexone, not naltrexone against other opioid treatments.