Vivus's obesity pill to be covered by Express Scripts Thu Dec 20, 2012 7:35am EST (Reuters) - Vivus Inc said its obesity drug Qsymia will now be covered by the largest U.S. pharmacy benefits manager Express Scripts Holding Co, giving more people access to the drug. Vivus shares were up nearly 4 percent in premarket trade. Express Scripts added Qsymia as a standard benefit option to its national formulary, which means patients will now pay about $50 to $60 as their co-payment on a monthly prescription of Qsymia, or about one-third of the retail price. Sales of Qsymia, one of the two new diet pills approved earlier this year after a dry spell of 13 years, were weak initially largely due to the lack of reimbursement coverage for the drug. Lackluster sales also prompted investor activism against Vivus, with its top shareholders calling for a sale of the company. However, last month health insurer Aetna Inc said it would provide coverage for both diet pills - Qsymia and Arena Pharmaceuticals Inc's Belviq. Vivus shares closed at $13.64 on Wednesday on the Nasdaq.