Roche won’t raise its $3 billion hostile bid on Ventana Medical Systems, chairman Franz Humer told Bloomberg News.

Roche’s bid is one of the biggest in biotech for recent years, surpassed only by AstraZeneca’s $15.6 billion acquisition of MedImmune, completed in June, Merck KGaA’s $13.3 billion acquisition of Serono in 2006 and Novartis’ $5.1 billion purchase of the remaining 58% of Chiron shares in 2005.

 The acquisition of Ventana would bolster Roche’s own diagnostics division and give the firm access to an important companion diagnostic. Ventana’s rabbit monoclonal antibody, PATHWAY HER-2/neu (4B5), won FDA approval in January for use as an aid in the assessment of prospective Herceptin patients with breast cancer. Herceptin is manufactured by Roche’s Genentech BioOncology.

Roche’s Humer told Bloomberg he was confident Ventana would “come around and see the attractiveness of our offer.” Ventana CEO Chris Gleeson told Bloomberg “We’ve said $75 [per share] is a non-starter. The market agrees with us.”

As of this morning, Ventana’s stock had slid a meager .48% to $82.61 on the NasdaqGS.