Gilead Boosted by Drug Data

Shares of Gilead Sciences Inc. shot up nearly 20% Monday after the company released encouraging data about its drug to treat hepatitis B.

Gilead jumped $7.13 to close at $43.25 on Nasdaq.

The Foster City, Calif.-based company also released strong data from clinical trials of Preveon, a related drug for treating HIV-infected patients.

Gilead said a phase II clinical trial of patients treated with adefovir dipivoxil for 12 weeks revealed a significant reduction in levels of the hepatitis B virus in the blood, making the infection almost undetectable in the majority of patients.

Gilead said the drug, taken once daily in a dose of 30 milligrams, reduced HBV DNA by as much as 99.99% with no significant side effects.

More than 5 million people in the United States and 300 million worldwide are estimated to be infected with the hepatitis B virus. The potentially fatal virus targets the liver and can cause liver failure, sclerosis and liver cancer. About 10% of HIV patients are infected with the virus.