Mylan NV said on Wednesday the U.S. Food and Drug Administration declined to approve its generic version of GlaxoSmithKline Plc’s blockbuster Advair asthma treatment, but provided no details of the agency’s concerns or how long the product might be delayed. Mylan’s shares fell 2.9 percent to $40.50, while GSK’s U.S.-traded shares rose 0.7 percent. Read…