According to Erik Walker in Trial magazine (11/10), "The defense in a pharmaceutical case will try to bury you in paper to keep your case from going before a jury. You can defeat every claim-killing motion with arguments grounded in sound legal reasoning and compelling facts."
This is from Walker's article, "Don't Get Papered Over." In the article, Walker suggests responses to two common defense attacks, the learned intermediary doctrine and the statute of limitations.
To summarize the responses here wouldn't do justice to Walker's work. If you're dealing with these issues, get your hands on the full text.