merck  co inc’s stock mrk rose 2 premarket thursday after the company posted betterthanexpected firstquarter earnings and offered guidance that topped estimates rahway njbased merck posted net income of 2821 billion or 111 a share for the quarter down from 4310 billion or 170 a share in the yearearlier period adjusted pershare earnings came to 140 ahead of the 132 factset consensus sales fell 9 to 14487 billion from 15901 billion also ahead of the 13793 billion factset consensus the profit decline was due to 52 cents of charges related to the acquisition of imago biosciences