All companies, not just pharmaceutical companies, have certain things that would be convenient and certain things that would be inconvenient if they were known. They will say what is convenient and will hide what is inconvenient. It's just more profitable.

That's where regulations come in to protect the public, but most of the time it's impossible to predict every lie people will say. That's why they lie about it, because they can get away with more lies because they have more money. It's also more profitable to lie than to tell the truth and that's why they do it.