PARIS, June 9 (Reuters) - French drugmaker Sanofi-Aventis (SASY.PA: Quote, Profile, Research) has suspended the enrollment of patients into clinical trials to test its antibiotic treatment Ketek following concerns about its safety. The U.S. Food and Drug Administration said last month that it and Sanofi were discussing possible revisions to prescription instructions for Ketek after researchers had reported that three patients using it developed severe liver damage and one died.