On Monday, Gilead Sciences Inc. announced The U.S. Food and Drug Administration (FDA) had approved the use of Viread for treating chronic hepatitis B. According to Gilead, the drug, that is to be taken once a day, blocks the enzyme called HBV DNA polymerase, which is needed by the virus in order to replicate. Up to this point, Viread had been used in the US by adults infected with HIV; such treatments began back in 2001.

Gilead Sciences Inc. is no stranger to chronic hepatitis B; one of the company’s drugs, Hepsera, is the most common oral agent for the condition in the US. Gilead is currently also working on ways to treat patients suffering from hepatitis C.

Viread has been acknowledged as a drug that actually works for chronic hepatitis B cases, as earlier this year it was approved in Australia, the European Union, New Zealand and Turkey.

According to Joel Sendek, an analyst of Lazard Capital Markets in New York, the company’s worldwide sales could reach no less than $810 million in 2009; when compared to the $600 million it is expected to bring in this year, it definitely looks like a step up for Gilead.

Ira Jacobson, chief of gastroenterology and hepatology at Weill Cornell Medical College in New York, said Viread will represent an important treatment option and the approval in the US provides a major boost in the fight against the condition.