Anadys Pharmaceuticals Inc (ANDS.O) said Swiss drugmaker Roche Holding AG (ROG.VX) agreed to buy the U.S. company for $230 million to broaden its portfolio of hepatitis drugs.

Roche, the world's biggest maker of cancer drugs, will pay $3.70 per share in an all-cash deal -- three-and-a-half times Anadys' Friday close of $1.04 on Nasdaq.

Anadys' shares rose to $3.68 before the bell on Monday -- 2 cents shy of Roche's offer price.

San-Diego, California-based Anadys, which has a market capitalization of about $60 million according to Thomson Reuters data, currently has two hepatitis C drug candidates in clinical trials.

Anadys had said last week that a mid-stage trial of its hepatitis C drug, setrobuvir, showed promise.

Setrobuvir, a direct-acting antiviral that works by interacting with and blocking a component of the virus, is in mid-stage trials, while ANA773, which is in early-stage development, works by stimulating the patient's own immune system to block cells infected with the virus.

Roche's third-quarter sales were hit by a fall in sales of its cancer medicine Avastin, and cuts in global healthcare spending throughout the year hurt the company.

The deal is expected to close in the fourth quarter this year.

Lazard is the financial advisor to Anadys and Cooley LLP is the legal advisor to the company, Anadys said in a statement.