First Circuit Reins In Broad Theory of Liability Under AntiKickback Statute by Adopting “But-For Causation” Standard

The First Circuit joins the Sixth and Eighth Circuits in adopting a more exacting causation standard for False Claims Act liability premised on Anti-Kickback Statute violations.

In a victory for False Claims Act (FCA) defendants, on February 18, 2025, the First Circuit, in United States v. Regeneron Pharmaceuticals, Inc., adopted a “but-for causation” standard for FCA liability resulting from Anti-Kickback Statute (AKS) violations. In aligning with the Sixth and Eighth Circuits, the First Circuit joins the recent judicial shift toward a more stringent standard requiring plaintiffs to prove that a kickback was the determinative factor in the submission of a claim, and not merely a contributing factor.