Illumina adopts takeover defense to ward off Roche SAN DIEGO (AP) - Diagnostics company Illumina Inc. says it is adopting a "poison pill" takeover defense in the wake of an unsolicited buyout effort by Swiss drugmaker Roche Holding AG. On Wednesday, Roche said it was planning a $5.7 billion tender offer for Illumina. The bid of $44.50 per share was an 18 percent premium over Illumina's closing stock price on Tuesday. It sent Illumina's share price soaring above the offered price. San Diego-based Illumina urged stockholders not to take action until it reviewed the proposal and made a recommendation. Roche, which specializes in cancer diagnosis and diabetes management, has a history of success with hostile offers.