Vivus Inc. reported disappointing sales for its obesity drug Qsymia (phentermine/topiramate), driving its stock price down more than 12 percent. The drug brought in $6.4 million in net revenue in the third quarter of 2013, missing consensus estimates of $12 million by a wide margin. The company’s net loss for the quarter was $48 million, or 48 cents per share, compared to a net loss of $40.4 million, or 40 cents per share, in the third quarter of 2012.