After a drawn-out battle that started last summer, the Swiss drugmaker finally clinched a deal for the 44 percent of the U.S. biotech group it didn't already own after Genentech's board recommended shareholders accept an increased offer of $95 per share in cash.

The deal is expected to be earnings-per-share-accretive in the first year after closing, Roche said in a statement, and the combined group would generate around $17 billion in annual revenues.

Roche's initial bid was rejected last year, and the Basel-based company turned hostile after several months, during which the financial crisis raised doubts about financing, and Genentech's shares fell below the offer price.

Buying Genentech would give Roche control of all revenues for big-selling cancer drugs Avastin and Herceptin, as well as absorbing an attractive portfolio of new medicines.

(Reporting by Katie Reid and Jason Rhodes, editing by Will Waterman)