Orexigen Therapeutics ( OREX) has been the best-performing obesity drug stock in 2013 despite not having an approved obesity drug to sell. The respective commercial launches of Vivus' ( VVUS) Qsymia and Arena Pharmaceuticals' ( ARNA) Belviq have underwhelmed this year, leading to a steep drop in their stock prices. So, it seems as if Orexigen has actually benefitted from the protracted FDA review and delayed commercial launch of its obesity pill Contrave. On Monday, Contrave passed a key heart-safety test, which should lead to the drug's approval next June. Will Orexigen and its marketing partner Takeda succeed where rivals have (so far) failed? Takeda has a lot of metabolic drug marketing experience -- Actos is a blockbuster diabetes drug -- which should proven beneficial with the Contrave launch. Orexigen's enterprise value is still significantly lower than Arena and Vivus.