NEW YORK (AP) — Swiss drugmaker Roche on Monday officially launched its $42 billion hostile offer for the 44 percent of Genentech Inc. it doesn’t already own. As expected, Basil, Switzerland-based Roche said it would pay $86.50 per share for all remaining publicly held shares of Genentech, developer of Avastin and other groundbreaking cancer treatments. Roche already holds a 56 percent stake in Genentech, which is based in South San Francisco, Calif. Roche’s latest offer, $2.50 per share less than an offer rejected by Genentech directors in July, has sparked concern from analysts that key personnel at the biotech pioneer could leave, depending on any potential deal. Roche estimated the deal value at $42 billion in a regulatory filing Monday. Roche said its new offer is aimed directly at shareholders, bypassing the board. The offer is significantly lower than the $100-per-share value analysts had been touting for several months. “While we have changed our approach to the transaction, our plan on how we will combine the two companies remains unchanged,” said Roche Chairman Franz Humer.The company’s offer expires at midnight March 12. Roche said it plans to complete the acquisition if it owns 90 percent of Genentech shares at that time. Separately, Genentech’s board committee urged shareholders to take no action with respect to the tender offer at this time. The committee said it will take a formal position regarding the Roche offer within 10 business days and explain its position in an upcoming regulatory filing.