A Randomized, Parallel Group, Double-Blind, Comparative Trial Assessing Lung Function and Other Measures of Asthma Control in Adults and Adolescents, at least 12 Years of Age, with Persistent Asthma, Who Have Either a B16-Arg/Arg, a B16-Gly/Gly or a B-16 Arg/Gly Genotype and are Treated With Fluticasone Propionate/Salmeterol DISKUS™ Combination Product 100/50mcg or Salmeterol DISKUS 50 mcg BID
