ZURICH, Jan 31 (,Reuters) –
Swiss drugmaker Roche (ROG.VX) is confident that it will succeed in its bid for U.S. biotechnology group Genentech Inc (DNA.N), the Swiss drugmaker's chairman was quoted as saying in comments released on Saturday.

"I am very confident that we will be successful in taking 100 percent of Genentech," Franz Humer was quoted as saying in an interview with Switzerland's Basler Zeitung.

Roche launched a surprise hostile bid for Genentech on Friday at a price below its initial rejected offer, reflecting tougher financing conditions and a drop in Genentech shares.

"The lower price reflects the value that we see in the company. Over the last year, the economic environment has changed," Humer said in the interview.

Roche is now making a public tender offer at $86.50 per share in cash for the 44 percent of Genentech it does not already own, valuing the deal at $42 billion and replacing its initial $44 billion bid.

Genentech said a special committee of its board would make a formal response within 10 business days of starting the tender offer and urged shareholders to take no action at this time. But it signaled another rejection in the offing.

(Reporting by Katie Reid; Editing by Jan Dahinten)