It only took seven months and five extensions since Roche first made its hostile bid, but a definitive merger agreement has finally been reached. But this comes at a price - Roche has agreed to pay $89.50 a share, up from the initial $75 offer, although quite close to the $90-a-share value that Ventana ceo Chris Gleeson insisted his company was worth all along. The deal works out to about $3.4 billion, up from Roche’s original $3 billion offer. Of course, a deal isn’t surprising, given that negotiations began in November after a few months of gamesmanship.

In a statement, the agreement companies note that the deal represents “a premium of 4.9 percent above Ventana’s closing price on January 18; a 19.3 percent premium above Roche’s initial offer on June 27, and a 72.3 percent premium above Ventana’s closing price on June 22, 2007 (the last trading day prior to the announcement of Roche’s initial offer).

Ventana, which will remain based in Tucson, Arizona, makes diagnostic tests that could be used to better detect cancers and use of medicines, such as Roche’s Herceptin. “Our combined company will be uniquely positioned to further expand Ventana’s business globally and together develop more cost-efficient, differentiated and targeted medicines,” says Roche ceo Franz Humer, in the statement. Gleeson, meanwhile, will continue as Ventana’s ceo after the deal is completed and become a member of Roche’s diagnostics executive committee.