On August 4, 2025, the District of Massachusetts granted the government’s motion for leave to file a second summary judgment motion and reopen discovery on a limited basis in its False Claims Act (FCA) suit against Regeneron Pharmaceuticals, opening the door for the government to pursue a false-certification theory of FCA liability in the wake of the First Circuit’s adoption of the stringent “but-for” causation standard for connecting a false claim and an alleged kickback.
In February 2025, as we summarized in a previous advisory, the First Circuit adopted the heightened but-for causation standard in Anti-Kickback Statute (AKS)-based FCA cases. Only the Third Circuit has arguably endorsed a more lenient standard, finding in United States ex rel. Greenfield v. Medco Health Sols. that in the pleading stage the government need only allege a “sufficient causal connection between an AKS violation and a claim submitted to the federal government.”
Joining the Sixth and Eighth Circuits, the First Circuit found that the “resulting from” language in the 2010 AKS amendment requires the government to prove not simply a mere “link” or “causal connection” between the alleged misconduct and the false claim but “that the AKS violation was a but-for cause of the false claim.” The AKS generally prohibits paying or receiving remuneration in exchange for health care referrals. Congress amended the statute in 2010 to create False Claims Act liability for any “claim that includes items or services resulting from a violation” of the AKS (42 U.S.C. § 1320a-7b(g) (emphasis added)). Since then, courts have disagreed on how qui tam relators or the government can prove that a claim “result[s] from” an AKS violation. The government has consistently argued that it did not need to prove that the alleged kickback caused the submission of false claims.
In Regeneron, the defendant manufacturer sold a drug that was partially covered by Medicare. The government alleged that the manufacturer improperly induced physicians to prescribe the drug by subsidizing copayments through a charity. The government alleged that claims submitted by physicians for those drugs “resulted from” an AKS violation making the Medicare claims “false or fraudulent” under the FCA, regardless of whether physicians would have submitted claims even if the manufacturer had not subsidized copayments. The district court rejected this theory at summary judgment, holding that more proof was required—namely, that the copayment subsidies actually caused improper prescriptions.
Applying this more stringent causation standard meant an uphill battle for the government, so after losing the causation standard fight in February, the Department of Justice (DOJ) pivoted and asked to file a second motion for summary judgment and to reopen discovery on a limited basis to pursue, for the first time, a false-certification theory. Before doing so, the DOJ was pursuing a theory under the 2010 amendment, which would have required the government to meet the more stringent but-for causation standard.
The government argued that its shift in strategy was justified because the First Circuit’s decision changed the applicable causation standard. In response, Regeneron argued that the government had waived this theory of liability by failing to allege it in its complaint.
The District of Massachusetts disagreed with Regeneron, holding the allegations in the complaint supported a false-certification theory. Even though the specific theory of liability was not mentioned, the complaint included allegations that, as a condition of payment, Regeneron was obligated to certify compliance with the AKS on CMS Form 8551 (the Medicare enrollment application) and that Regeneron submitted claims for payment despite receiving illegal copay subsidies.
The district court also rejected Regeneron’s waiver argument, noting that the First Circuit’s decision “amounted to a critical shift in the applicable law.” It concluded that the government was seeking leave to start a new round of summary judgment briefing on the false-certification theory rather than raising the theory “in the course of a summary judgment-process already in full swing.” While the district court acknowledged that “typically, a plaintiff must bear the risk that its choice of litigation strategy ultimately proves problematic,” but it would be “unfair in these circumstances to chain the government to such a choice when the legal ground shifts somewhat dramatically mid-way through the litigation.”
The government’s deadline to file its second motion for partial summary judgment is October 1, 2025.
If you have any questions, or would like additional information, please contact one of the attorneys on our Health Care Litigation team.
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