(Reuters) – Vivus Inc’s silence on its strategy to boost sales of obesity drug Qsymia has increased doubts about whether the pill will reach its full commercial potential. Qsymia was the first diet pill to launch in the United States in more than a decade. But both doctors and patients have shown reluctance to embrace it and other diet pills, including Arena Pharmaceuticals Inc’s Belviq, because of the long history of safety concerns surrounding diet treatments. Analysts said on Tuesday that Vivus, with its limited sales force, needed a partner to ensure the drug’s success.