Complex sentence: A phase III trial of 1200 mg/d and 2400 mg/d for Parkinson's disease was discontinued early for lack of effectiveness in August 2011, and concluded, The investigational drug is unlikely to demonstrate efficacy over placebo for this indication.
Split into simpler sentences: A phase III trial of 1200 mg/d and 2400 mg/d ran until August 2011. This study was terminated and the summary concluded: The investigational drug is unlikely to demonstrate efficacy over placebo for this indication.