The investigators found that among opioid users in NEW HOPE, viral suppression levels (fewer than 50 copies/mL) improved from 37.9% at baseline to 60.6% at 6 months among 66 individuals who received XR-NTX (P = .002). In contrast, viral suppression among 27 placebo users dropped from 55.6% at baseline to 40.7%, although this decline was not statistically significant.
In multivariate analysis controlling for treatment arm, cocaine-use disorder, homelessness, or number of injections received, the only significant predictor for viral suppression at 6 months was XR-NTX vs. placebo (odds ratio, 2.90; P = .043). There were no serious adverse events in this study.
Among those with alcohol-use disorders in the INSPIRE study, the changes in viral suppression were similar to those in the NEW HOPE study, improving from 31% at baseline to 56.7% at 6 months among 67 participants in the XR-NTX arm (P = .001), compared with a decline from 42% to 30.3% among 33 participants in the placebo arm, although again this difference was not significant.
In the INSPIRE study, significant predictors of viral suppression at 6 months included naltrexone XR (OR, 4.54; P = .009), three or more injections (OR, 6.34; P = .001), white vs. black or Hispanic (OR, 5.37; P = .040), and alcohol improvement score, a composite measure of drinking parameters (OR, 1.43; P =.033).