United Therapeutics Corp. has prevailed in a legal effort to slow Sandoz Inc.'s plans to launch a generic version of the pulmonary arterial hypertension (PAH) therapy Remodulin (treprostinil), a drug that accounted for 44 percent of its revenue last year. The patent case ruling forestalls generic competition from Sandoz for at least three years and may block an additional challenge from Teva Pharmaceutical Industries Ltd. until then as well.