An implantable form of naltrexone may be more effective at helping patients with HIV who have an opioid addiction reduce drug relapse and subsequent nonadherence to their antiretroviral therapy (ART), according to a study published in Lancet HIV.
 
Untreated opioid addiction in individuals with HIV can lead to negative treatment outcomes. For the study, the researchers assessed whether a slow-release, long-acting, implantable naltrexone could improve outcomes for patients with HIV and opioid addiction.
 
The phase 3 study enrolled 200 patients seeking treatment for HIV and opioid dependence and assessed HIV and addiction treatment outcomes over the next 12 months. All of the study participants had not been on HIV treatment for at least 1 year and had viral loads more than 1000 copies per mL. For the study, patients received either the naltrexone implant every 12 weeks along with daily placebo oral naltrexone or oral naltrexone 50 mg per day along with a placebo implant.
 
The researchers noted that the study was conducted in Russia, where oral, extended-release injectable, and implantable naltrexone products are approved, but agonist or partial agonist maintenance using medications are illegal. 
 
Based on the study results, the naltrexone implant was associated with more patients with HIV maintaining their ART regimen and lowering viral loads compared with the implantable drug than with the oral form.
 
According to the findings:
  • At week 24, 38 patients in the implant group and 35 in the oral group had viral loads less than 400 copies per mL.
  • At week 48, 66 patients in the implant group and 50 in the oral group had viral loads less than 400 copies per mL.
  • Forty-six patients in the implant group remained on ART compared with 32 in the oral drug group at the end of the study.
  • Patients in the implant group remained on addiction treatment without relapsing longer than the oral drug group (32 weeks versus 20 weeks). 
According to the researchers, the patients in the implant group likely had better outcomes due to longer periods of remission, which allowed them to focus more on HIV treatment. Overall, the longer the blockade of opioid effects, the more protection a patient received from missed ART doses and impulsive behaviors that lead to relapse and poor outcomes, the researchers concluded.
 
“The findings have implications for treatment of opioid dependence among patients that do not want agonist maintenance or who live in places where options are more limited,” senior author George E. Woody, MD, an emeritus professor in the department of Psychiatry at the Perelman School of Medicine at the University of Pennsylvania, said in a press release. “Further development and formal approval of these implants in a wider range of cultural settings has the potential to provide an effective and meaningful HIV and opioid treatment option for these patients.”
 

References
 
Krupitsky E, Blokhina E, Zvartau E, et al. Slow-release naltrexone implact versus oral naltrexone for improving treatment outcomes in people with HIV who are addicted to opioids: a double-blind, placebo-controlled, randomized trial. The Lancet HIV. Published March 14, 2019. Doi: https://doi.org/10.1016/S2352-3018(18)30362-X
 
Naltrexone Implant Helps HIV Patients with Opioid Dependence Adhere to Medications, Prevent Relapse [news release]. Penn Medicine. https://www.pennmedicine.org/news/news-releases/2019/march/naltrexone-implant-helps-hiv-patients-with-opioid-dependence-adhere-to-medications-prevent-relapse. Accessed March 22, 2019.