GlaxoSmithKline PLC formally terminated a clinical trial of an experimental drug designed to harness the potential health benefits of red wine, saying it had minimal efficacy in cancer patients and could potentially exacerbate kidney complications. The U.K. drug maker also reiterated that it isn't planning any further testing of the drug, SRT501, because it is focusing on other compounds designed to work similarly to SRT501 but which differ chemically.