LOS ANGELES Gilead Sciences said on Monday it won U.S. approval to promote its AIDS drug Viread for treating adults with chronic hepatitis B.
Hepatitis B is a potentially life-threatening infection that can destroy the liver. Gilead estimates that more than 400 million people worldwide have the disease, which is most prevalent in Asian countries. It is the leading cause of liver cancer and complications kill up to 1.2 million people per year.
Viread, known generically as tenofovir, is a once-daily tablet that works by blocking an enzyme necessary for the virus to replicate in liver cells.
The drug has been available in the United States as a treatment for HIV infection in adults since 2001.
Gilead already markets another hepatitis B drug, Hepsera, which saw second-quarter sales of $90 million.
RBC Capital Markets analyst Jason Kantor estimated that Hepsera currently has 44 percent of the market, which remains significantly underserved.
"Compared to the available drugs, Viread is likely to be considered best-in-class based on its potency, resistance profile, long-term safety, and price," he said in a recent research note.
Truvada, which had second-quarter sales of $516 million, is a pill that combines Viread with Emtriva, another of Gilead's HIV drugs.
Shares of Gilead, which lost 34 cents to close at $56.43 on Nasdaq, were slightly higher at $57.23 in after hours trading. Year-to-date, the stock is up about 24 percent, compared with a gain of about 11 percent for the Biotech Index.
(Reporting by Deena Beasley in Los Angeles and Lisa Richwine in Washington; editing by Carol Bishopric)