As Facebook gradually opened pharmaceutical industry pages to public commenting this week, some companies said they had not yet seen troublesome comments, while others continued to move offline to avoid potential risks. Facebook reversed a policy that exempted all drug company pages from open "walls." Pages focused on companies themselves and on disease or patient-specific communities are now open to comments, while those focused on a specific prescription product continue to be closed. Companies have worried that open walls may lead to the reporting of bad side effects, promotion of off-label use or inappropriate statements -- all of which could raise concern from government regulators. Like other Facebook users, companies can delete comments once they've been posted. Sanofi, which maintains pages related to diabetes and pertussis (whooping cough), as well as a company page, has seen no problems from the more than 66,000 people who "like" its pages, according to spokesman Jack Cox. Pfizer also has not had any issues, said spokesman Andrew Widger, and monitoring is "running smoothly" for its hemophilia and multiple sclerosis pages, which have more than 3,900 "likes" combined.