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Gilead's HCV Therapy Trials On Track

March 1, 2013

Last month, Gilead Sciences reported that it had met its goals in two late-stage hepatitis C virus (HCV) drug trials. The trials, called Fission and Neutrino, incorporated the experimental HCV drug sofosbuvir as part of a combination 12-week therapy in previously untreated patients with chronic HCV. 

Gilead is one of several companies investigating alternatives to the existing standard of treatment for HCV--weekly injections of pegylated interferon (peg-IFN) and a daily ribavirin (RBV) oral pill. This regimen is not ideal, as nearly 50% of patients do not respond to it. In addition, those who do respond often experience debilitating side effects that can last the duration of the treatment—either 24 or 48 weeks. Pharmaceutical companies are experimenting with interferon-free regimens to see if they can eliminate some of the challenging side effects.

Fission evaluated the once-daily nucleotide sofosbuvir pill in combination with ribavirin. Patients with HCV infection were selected at random to receive either a 12-week course of sofosbuvir plus RBV, or standard of care with 24 weeks of peg-IFN plus RBV. The study met its primary goal, demonstrating that sofosbuvir plus RBV was as effective as the standard treatment of peg-IFN/RBV. Overall, 67% of patients achieved a sustained virologic response (SVR) in each of the treatment groups. SVR signals that a patient has “cleared” the virus for at least six months after completing therapy. It is achieved when viral levels drop, becoming nearly undetectable. Patients in the standard of care group experienced more side effects, including fatigue, headache, nausea, insomnia and dizziness.

In the Neutrino trial, patients were given sofosbuvir plus peg-IFN/RBV. This study met its primary goal of achieving superiority, with 90% of patients achieving SVR vs. a 60% cure rate for RBV and peg-IFN, based on historical expectations. About 20% of subjects experienced such side effects as fatigue, headache, nausea, insomnia and anemia.


Source: Reuters, February 4, 2013