Facebook clearly does not know much about the pharmaceutical industry or the current debates going on in the industry about the role social media plays. I do consulting work for the pharmaceutical industry and have done a lot of work specifically with manufacturer sponsored web portals, use of social media, and drug safety in general. I can't say one way or another whether any of these companies should take down their pages, but there is very real risks involved with keeping them open. This has nothing to do with conspiracies about silencing bad publicity or any of the other crackpot theories out there. This has everything to do with the FDA and not getting fined or sued into oblivion. Here are some of the issues facing the pharma industry and social media:
Adverse Events: This is the official title for "when bad shit happens while taking our drug." This could be anything from a runny nose to death. Mostly only the more serious stuff even gets reported, but regardless, if something negative happens while taking a drug, the manufacturer wants to know about it. Not only that, but the FDA requires regular reporting on this. However, there are certain qualifications for an Adverse Event to be official. You need a drug, a patient, an event, and an indication (what you were taking it for). Without all 4, you don't have a reportable adverse event. The issue here is that the pharma company is worried about AE's reported over the internet in chatrooms and forums and what their responsibility is around this. The FDA has not yet made this crystal clear, but everyone seems to agree that you need to follow-up on any events posted to your own sites. For independent sites, you should be doing monitoring, but you don't need to report to the FDA unless the event is reportable (meets the 4 criteria). Due to the anonymity of online posts, this is usually impossible.
Off Label Use of Drugs: Off label use means the drug is being used for an indication that the FDA has not approved the drug for. This is very common with cancer treatments or any other areas where treatments are often experimental in nature. The drug may be approved by the FDA for treatment of diabetes, but a doctor may find that it is effective against a certain cancer. The FDA may approve this use in the future, but until that time, the manufacturer is not allowed to promote this type of use (Pfizer has been fined billions for violating this in the past few years). If people promote off label on 3rd party sites, then that's fine, but it cannot appear on a manufacturer owned site. Even though it's Facebook, it still counts as the manufacturers site.
Fair Balance: You know when you watch a commercial for a drug and after telling you all about the wonderful things a really fast voice tells you about all of the side effects and what not that might not be so great? That's called fair balance and it is required by the FDA. You see it on all of their web sites too. Anytime a promotional claim is made about a drug, fair balance must be provided. This has made twitter use very tricky since fair balance statements usually go way beyond 140 characters. If someone posts on the manufacturer's facebook page that the drug did something wonderful for them, then there needs to be fair balance attached. That can be tricky if you you're the manufacturer, since not only do you have to provide fair balance for your statements, but also for everyone else's.
The FDA has yet to provide guidance on social media: This is the biggest thing of all and it is why each of the points I made above are an issue. The rules of the FDA were not created when social media existed and they still have not been interpreted into social media by the FDA themselves. I'm sure there are some reasonable exceptions or changes that could be made given the current use of the medium overall, but we just don't know for sure yet. Most companies are cautiously making their own best guesses on what they feel is reasonable and still keeps them covered, but these are best guesses and the FDA could still fine them. The FDA has promised guidance, but keeps delaying. Until they do provide guidance, many companies will be super conservative (like those who just took down their pages) and others will be a little more brave, but it is risky just to be in social media at all as a pharmaceutical company.