Merck’s Zepatier (grazoprevir/elbasvir) cures hepatitis C virus (HCV) at high rates among people with opioid use disorder (OUD), according to a pair of real-world studies.

Presenting their findings at the 53rd International Liver Congress in Vienna, researchers analyzed data from the German Hepatitis C Registry (DHC-R) regarding 992 people with genotype 1 of HCV who received 12 or 16 weeks of Zepatier treatment with or without ribavirin.

There were sufficient data to determine the cure status of 613 people. Of this group, 499 had no history of drug use, 67 were people who inject drugs (PWID) taking medication-assisted treatment (MAT) for OUD and 47 were either former or current PWID not taking MAT. The rate of those who achieved a sustained virologic response 12 weeks after completing therapy (SVR12, considered a cure) was 96.2 percent (480 of 499), 89.6 percent (60 of 67) and 93.6 percent (44 of 47) in each of the three groups, respectively.

The difference in the cure rate was statistically significant, meaning it is unlikely to have been driven by chance, between those with no history of drug use and those taking MAT.

When the study authors excluded from their analysis those who did not finish treatment or who were lost to follow-up, the cure rates in the three groups were 98.6 percent (484 of 491), 98.4 percent (61 of 62) and 95.7 percent (44 of 46), respectively. There was no statistically significant difference between these three rates.

In a second study presented at the conference, researchers analyzed data regarding 611 U.S. veterans with genotype 1 of HCV who received Zepatier for at least 12 weeks and who either were diagnosed with OUD or had been prescribed MAT. Ninety percent of the participants were taking their first HCV regimen. Eighty-six percent had Stage 4 or 5 of chronic kidney disease. Fifty-nine percent had received at least one prescription for MAT, 90 percent had a history of drug abuse and 71 percent were taking psychiatric medication.

Eighty-six percent (526 of 611) received Zepatier without ribavirin for 12 weeks. The remaining participants received other Zepatier-based regimens.

Between 94 and 98 percent of the study cohort’s various subgroups achieved a sustained virologic response 12 weeks after completing therapy (SVR12, considered a cure), including those with an initial viral load of at least 800,000, those with cirrhosis, those with a history of alcohol or drug abuse and those taking MAT.