Gilead Sciences has reported positive topline results from two Phase III studies, FISSION and NEUTRINO, of sofosbuvir conducted in patients infected with hepatitis C virus (HCV) and who were new to the treatment.

Sustained virologic response (SVR) rates were achieved and primary endpoints were met in both studies.

A 12-week course of the once-daily nucleotide sofosbuvir plus ribavirin (RBV) was evaluated in FISSION study whereas sofosbuvir in combination with RBV and pegylated interferon (peg-IFN) was assessed in NEUTRINO study.

Gilead Sciences chief scientific officer and research and development executive vice president Dr Norbert Bischofberger said the data supports the clinical profile of sofosbuvir as a potent, safe and well-tolerated treatment regimen effective across a range of HCV patient genotypes.

"The sofosbuvir regimens in these trials allowed us to shorten the duration of effective hepatitis C therapy to just 12 weeks for treatment-naïve patients with genotypes 1 through 6," Bischofberger said.

The 67% of patients in the FISSION achieved a SVR in the sofosbuvir plus RBV treatment group compared to 67% in the pegylated interferon alfa-2a (peg-IFN) plus RBV treatment group.

The FISSION study met its primary efficacy endpoint of non-inferiority of sofosbuvir plus RBV to peg-IFN plus RBV, demonstrating common adverse events such as fatigue, headache, nausea, insomnia and dizziness.

NEUTRINO study met its primary efficacy endpoint of superiority compared to a predefined historic control SVR rate of 60% with 90% of patients achieving SVR12 after completing therapy.

Fatigue, headache, nausea, insomnia and anemia were the most common adverse events that occurred in the NEUTRINO study.

Image: Electron micrographs of hepatitis C virus purified from cell culture. Scale bar is 50 nanometers. Photo: Courtesy of the Center for the Study of Hepatitis C, The Rockefeller University.