Roche will pay $74 a share for InterMune, which represents a 38% premium to Friday's closing price of $53.80, in an all-cash deal.
Ariad was up 6.43% to $6.62 at 12:35 p.m. More than 8.3 million shares had changed hands to edge the average volume of 8,129,760.
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ARIA data by YCharts
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