In the following video, Motley Fool health-care analyst David Williamson highlights a potential new threat to an entire class of multibillion-dollar drugs. The drug group, which treats type 2 diabetes, could be linked to pancreatitis, a very serious inflammation of the pancreas that can lead to pancreatic cancer. David tells investors how several companies, such as Merck (NYSE:MRK), Bristol-Myers Squibb (NYSE:BMY) and AstraZeneca (NYSE:AZN) could be affected if the link is confirmed, and how serious the damage could be financially.

David Williamson and The Motley Fool have no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.