The Supreme Court ruled on June 23, 2011, that generic drug manufacturers cannot be sued for a failure to warn under state tort law, as long as their labeling complies with the FDA mandated labeling for the innovator drug product. While the Court had previously declined to find that federal regulation and approval of drug labeling of an innovator drug preempted state tort law in Wyeth v. Levine, 555 US 555 (2009), the Court ruled 5-4 in Pliva that the comprehensive scheme for approval of generic drugs under the 1984 Hatch-Waxman amendments required generic manufacturers to use the same labeling as the innovator brand name product.

Since the law and FDA regulations, as conceded by the Food and Drug Administration (FDA), preclude a generic company from obtaining approval of labeling different from the innovator brand name product, the Court held it was not possible for a generic manufacturer to comply with both federal and state law. As such, under the doctrine of impossibility, they ruled federal law was supreme and state tort laws on failure to warn were preempted. In so finding, they held that the issue of “impossibility” turns on whether the private party could independently do under federal law what state law requires of it. In this case, they held that generic manufacturers could only ask FDA to change labeling and could not do so without FDA approval, and thus could not act independently.