Federal law preempts the claims plaintiffs are making that incretin-based drugs caused their pancreatic cancer, a group of drugmakers argued in their latest court filing on the issue. The defendants say there is no clear evidence the U.S. Food and Drug Administration would have changed the warnings given on the risks of those drugs.

Even though the U.S. Supreme Court ruled in Wyeth v. Levine that federal regulatory approval of a brand-name drug does not shield pharmaceutical companies from state tort lawsuits, now the FDA can require a labeling change if it becomes aware of new safety information that should be included in drug labeling, the drugmakers said. That was not possible at the time Levine was decided.