A six-week treatment regimen appeared to be as effective as the more standard 12 weeks of therapy for patients with hepatitis C virus infections, findings from the SYNERGY trial suggest.

The pilot study involved a cohort of 60 treatment-naive, mono-infected patients with HCV genotype 1 (20 patients in each arm) and assessed three direct-acting antiviral combination therapies:

  • A fixed dose combination of sofosbuvir 400 mg (Solvadi, Gilead) with ledipasvir 90 mg once daily for 12 weeks
  • Fixed-dose combination plus 500-mg of NS5B inhibitor GS-9669 (Gilead) daily for six weeks
  • Fixed-dose combination plus 80 mg of the HCV protease/NS3/4 inhibitor GS-9451 (Gilead) daily for six weeks

Outcomes in the 12 weeks post treatment (SVR12) were similar among all treatment arms, Anita Kohli, MD, of the Critical Care Medicine Department at the National Institutes of Health Clinical Center in Bethesda, Md., reported at the 2014 Conference on Retroviruses and Opportunistic Infections.

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All patients treated with the combination of sofosbuvir 400 mg with ledipasvir 90 mg once daily for 12 weeks achieved SVR12.

Among those assigned to the six-week fixed-dose combination with GS-9669 or GS-9451, SVR12 rates were 95% and 100%, respectively.

The study cohort was comprised 80% of black patients; 72% males; 70% had HCV genotype 1a; 70% had a viral load >800,000 IU/L; and 82% had an IL28B non-CC haplotype.

“We feel confident that the HCV population included in this study is reflective of the HCV population in the United States,” Kohli said. “This population has historically been difficult-to-treat.”

Overall, viral relapse occurred in only one patient assigned the GS-9669 arm before week 4 of treatment. This patient had stage-3 liver disease, a high viral-load and an unfavorable genotype, according to Kohli.

“Hepatitis C can be safely and effectively treated in 6 weeks using three direct acting agents with different mechanisms of action,” Kohli said. “We feel that this short duration, simple therapy for HCV may prove relevant for the global eradication of HCV, where uncomplicated, well-tolerated therapy is required to ensure adherence and minimize health care expenditures.”

Ledipasvir is not currently approved in the United States, but manufacturer Gilead, filed for FDA approval of the drug in a fixed-dose combination with sofosbuvir in March 2014.


  1. Kohli A. Abstract #27LB. Presented at: 2014 CROI. March 3-6, 2014. Boston.