Study confirms sofosbuvir-ribavirin works against HCV genotype 2

A large, international cohort study confirms the real-world effectiveness and safety of the all-oral combination of sofosbuvir plus ribavirin for treatment of hepatitis C virus (HCV) genotype 2 (GT2) infection.

The study from 44 academic and 17 community medical centers in North America and Europe included 321 sequentially enrolled patients, median age 59 years, with chronic HCV GT2 infection who were treated in routine clinical practice.

The researchers published their results online July 13, 2016, in Gut.

Overall, 88.2% of patients achieved sustained virologic response at 12 weeks (SVR12). For those without cirrhosis, the SVR12 was 91% for 12 weeks and 92.9% for 16 weeks of therapy. In patients with cirrhosis treated for 12 or 16 weeks, SVR12 was 79% and 83%.

A multivariate analysis found that liver cirrhosis, lower serum albumin and ribavirin dose at baseline were significantly associated with SVR12.

Only 2.8% of patients discontinued therapy due to adverse events.

“This study confirms what would be expected from the phase III trials – patients with cirrhosis have a higher risk of treatment failure when treated with only 12 weeks of therapy. The benefit of extension to 16 weeks is unclear here due to the small numbers,” Susanna Naggie, MD, associate professor of medicine at Duke University told Medical Economics as an expert unrelated to the study.

“In the real world, getting access to 16 or 24 weeks of treatment when the package insert recommends 12 weeks is extremely difficult, which puts patients at risk of relapse due to inadequate representation of these more difficult-to-treat patients in the registration studies,” she added.

One of the key findings of the study, said Naggie, was the high relapse rates in patients with cirrhosis. “Cirrhosis was under represented in the clinical trials. This study sheds light on the strong predictor of failure that is cirrhosis.”

The finding that initial ribavirin dose is an independent predictor of treatment failure is also important, she said. “The SPARE trial investigated this same regimen for 24 weeks in genotype 1 infection and also found that lower ribavirin dose increased risk of relapse. This study now shows that inadequate weight-based ribavirin dosing can significantly impact the success of a regimen that contains a single direct-acting antiviral,” said Naggie.

She noted that sofosbuvir/ribavirin is no longer a recommended regimen for GT2 infection. “This is because sofosbuvir/velpatasvir was studied in a head-to-head comparison vs sofosbuvir/ribavirin and was superior in achievement of higher SVR. Furthermore, the wholesale acquisition cost (WAC) of sofosbuvir/velpatasvir is lower than of sofosbuvir alone, thus based on WAC/wholesale cost, there is no cost benefit either.”

The approval of sofosbuvir/velpatasvir has brought a generalizable approach to therapy, in which 12 weeks of the fixed-dose combination is appropriate for the vast majority of patients, Naggie said. “HCV therapy has finally come to the point that there is no need to wait for the next best thing. The SVR rates that we can now achieve leave little room for improvement. Thus there must now be aggressive efforts to identify patients and get them engaged in care and on therapy,” she said.