Gilead Sciences ($GILD) is sprinting ahead with initial positive results from a Phase III study for what could be a first all-oral combination therapy for certain patients with chronic hepatitis C virus in the U.S. The company reported clinical cures for about three quarters of patients with genotypes 2 or 3 of the liver-damaging virus on a combination of its experimental "nuc" sofosbuvir or GS-7977 and standard ribavirin.
In a crowded and fast-moving contest to grab a piece of a potential $20 billion market for interferon-free treatments, Gilead has established the lead spot with all-oral cocktails built around sofosbuvir. Its latest trial results come from the first of three late-stage studies of the once-daily nucleotide analog polymerase inhibitor in patients with genotypes 2/3, and Gilead aims to file for FDA approval of the drug in mid-2013. Results from the other late-stage studies are due early next year.
Wall Street has come to expect great things from Gilead's hep C program, which wowed analysts earlier this month with 100% of patients with genotype 1 in a small Phase II study showing no signs of the virus after taking sofosbuvir, Gilead's NS5A inhibitor GS-5885 and ribavirin. The company will report Phase III results next year for a combo treatment against genotype 1, the most common form of the disease.
As Gilead showed today, the company's all-oral regimens won't wipe out the virus in all patients every time. However, the drugmaker points out that members of the genotype 2/3 population in the Phase III study, called "Positron," have no other approved treatment options because they are unable or unwilling to take injections of interferon, which is part of the standard of care.
For those that took sofosbuvir and ribavirin in the study, 78% of them achieved a sustained virologic response. None of the patients on placebo was cured in the study. Also, Gilead showed that the safety of sofosbuvir was consistent with previous trials, reporting that the most common adverse events included fatigue, nausea, headache, insomnia, pruritis and anemia.
"Just as important, all patients receiving sofosbuvir/[ribavirin] became HCV negative on treatment, and relapse accounted for all virologic failure, suggesting resistance to sofosbuvir has still not been produced in patients," Cowen wrote in a note to investors today, commenting on the data.
Gilead is racing against Abbott Laboratories ($ABT), which also has a Phase III program for an all-oral combo against hepatitis C, and Bristol-Myers Squibb ($BMY), which could be the first to market with an interferon-free regimen in Japan.
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