(HealthDay News) – Subcutaneous injections of miravirsen, an miRNA inhibitor, result in significant virologic responses in patients with chronic hepatitis C virus (HCV) infection, according to a study published online March 27 in the New England Journal of Medicine.

Harry L.A. Janssen, MD, PhD, from Erasmus MC University Hospital in Rotterdam, Netherlands, and colleagues conducted a Phase 2a trial at seven sites. Miravirsen was evaluated in 36 patients with chronic HCV genotype 1 infection who were randomly assigned to receive five weekly subcutaneous injections of miravirsen (3mg/kg, 5mg/kg, or 7mg/kg) or placebo over a 29-day period. Follow-up lasted for 18 weeks after randomization.

The researchers found that there was a dose-dependent reduction in HCV RNA levels with miravirsen that was sustained beyond active therapy. The mean maximum reduction in HCV RNA level from baseline was 1.2 (log10 IU per millileter) in patients receiving 3mg/kg (P=0.01); 2.9 for 5mg/kg (P=0.003); and 3 for 7mg/kg (P=0.002) vs. 0.4 reduction with the placebo. One patient in the 5-mg group and four patients in the 7-mg group had no detectable HCV RNA over the 14 weeks of follow-up after treatment. No escape mutations in the miR-122 binding sites of the HCV genome were detected. There were no dose-limiting adverse events.

“The use of miravirsen in patients with chronic HCV genotype 1 infection showed prolonged dose-dependent reductions in HCV RNA levels without evidence of viral resistance,” the authors write.

The study was funded by Santaris Pharma, the manufacturer of miravirsen.

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