Gilead Sciences Scores First Win With Late-Stage Hep C Study

FOSTER CITY, Calif. ( TheStreet) -- Gilead Sciences ( GILD) reported positive results Tuesday from the first in a series of late-stage studies to support the regulatory approval of its hepatitis C pill sofosbuvir.

If approved, sofosbuvir will be the main component of the first all-oral combination regimen to treat hepatitis C, eliminating the need for traditional injectable drugs.

Gilead expects to seek approval of sofosbuvir in the middle of 2013.

This first phase III study, dubbed POSITRON, examined a 12-week course of therapy consisting of sofosbuvir (formerly known as GS-7977) plus the immune booster ribavirin. The study enrolled patients with genotype 2 or 3 hepatitis C who were not candidates for treatment with interferon, the injectable drug commonly used today.

Genotype 2/3 is less common in the U.S. than genotype 1 but still represents about one-third of all hepatitis C cases worldwide.

Seventy-eight percent of patients treated with sofosbuvir and ribavirin for 12 weeks achieved a sustained virologic response (SVR), the medical term that denotes a cure for hepatitis C. By comparison, none of the patients treated with a placebo in the study achieved a cure.

The 78% cure rate for sofosbuvir plus ribavirin met but didn't exceed Wall Street expectations, said ISI Group analyst Mark Schoenebaum, in an email to clients.

"As Gilead is a very high expectation stock, we would not expect the stock to move up much at all today, and could even trade down a bit," Schoenebaum writes.

Gilead shares were down less than 1% to $75 in early Tuesday trading.

Two additional phase III studies of sofosbuvir in genotype 2/3 patients are underway with results expected in the first quarter 2013. Phase III studies of sofosbivir in the more prevalent genotype 1 hepatitis C patient population are also being conducted, with results expected next year.

Gilead most promising and anticipated hepatitis C regimen consists of sofosbuvir, a so-called "nuc" polymerase inhibitor plus GS-5885, an NS5A inhibitor.

Abbott Labs ( ABT) has begun phase III studies of its own all-oral hepatits C regimens.

-- Reported by Adam Feuerstein in Boston.

Adam Feuerstein writes regularly for TheStreet. In keeping with company editorial policy, he doesn't own or short individual stocks, although he owns stock in TheStreet. He also doesn't invest in hedge funds or other private investment partnerships. Feuerstein appreciates your feedback; click here to send him an email.