Plaintiffs appealing defense verdicts in the first bellwether trials over the blood thinner Xarelto are fighting back against an attempt by the drug manufacturers to toss out all 20,000 cases in federal court on federal pre-emption grounds.

Plaintiffs had appealed verdicts in three bellwether trials before the U.S. Court of Appeals for the Fifth Circuit, insisting that the jury’s findings were due to improper jury instructions and evidentiary rulings. But Johnson & Johnson’s Janssen Pharmaceuticals Inc. and Bayer Pharma AG filed a cross-appeal last year, arguing that Xarelto labels clearly warned of excessive bleeding and, as a result, federal pre-emption warranted tossing “the overwhelming majority of the pending cases.” U.S. District Judge Eldon Fallon in the Eastern District of Louisiana had denied summary judgment on those grounds before trial.

“Defendants raised and re-raised this affirmative defense throughout this litigation, but each time, the district court rejected defendants’ arguments and ruled that federal law does not preempt any claims at issue,” wrote plaintiffs attorney Frederick Longer in a response filed on Friday.

He wrote there was no “clear evidence” that the U.S. Food and Drug Administration would have rejected the revised warning label plaintiffs wanted: One that advised doctors to administer a laboratory test to assess a patient’s bleeding risks before prescribing Xarelto.

The same argument over the “clear evidence” standard has come up in several tort cases against drug manufacturers. Earlier this month, the U.S. Supreme Court heard oral arguments in a case over whether there was “clear evidence” that the FDA would have rejected a warning on Merck’s osteoporosis drug Fosamax.

Longer, of Philadelphia’s Levin Sedran & Berman, did not respond to a request for comment. Lisa Blatt, a Washington, D.C., partner at Arnold & Porter who plans to join Williams & Connolly next week, represented Bayer.

“We believe the Fifth Circuit should affirm these three verdicts. Plaintiffs had a full and fair opportunity to present their theories to the jury, and their disagreement with the verdicts is no basis for reversal,” wrote Bayer spokesman Dan Childs. ”Plaintiffs’ attorneys in these cases have presented multiple theories regarding the alleged inadequacy of the Xarelto label, and all of their claims have ultimately been rejected under applicable laws.”

As to the preemption argument and the Supreme Court case, Merck Sharp & Dohme Corp. v. Albrecht, he wrote: ”While we continue to believe these cases are preempted by federal law, appellate review should follow the U.S. Supreme Court’s ruling in Albrecht. We look forward to re-filing our preemption arguments after the Supreme Court has answered this important question.”

Janssen was represented by Susan Sharko at Drinker Biddle & Reath in Florham Park, New Jersey. Janssen spokeswoman Sarah Freeman wrote in an emailed statement: “We stand behind the safety and efficacy of Xarelto (rivaroxaban) and believe its FDA-approved labeling has always appropriately informed physicians of the information that they need to make treatment decisions with their patients. The prescribing information for Xarelto clearly, prominently, and repeatedly warns of the risk of bleeding, which is a known risk associated with all anticoagulants.”

Lawsuits allege that Xarelto, an anti-coagulant used to treat blood clots, caused plaintiffs to suffer from uncontrollable internal bleeding. The Xarelto litigation is among the biggest mass torts in the country. In addition to the federal multidistrict litigation, there are about 2,000 lawsuits pending in the Philadelphia Court of Common Pleas, where juries also have come out with defense verdicts. A trial judge in the Philadelphia cases reversed the only plaintiff’s win so far: a $28 million award in 2017.

In federal court, three bellwether trials occurred in 2017. Juries found the warning labels that the FDA approved were adequate.

In an April 23 brief, plaintiffs appealed the verdicts. In particular, they alleged Fallon, the judge, should have included evidence of Xarelto labels that regulators in other countries had approved recommending the laboratory test. Jurors in the third trial also should have heard about “striking new evidence”: a Bayer study that backed up the use of the test, they wrote.

Janssen and Bayer defended Fallon’s rulings in a June 7 response, then added their own appeal arguments.

“The court could resolve these three cases simply be rejecting plaintiffs’ evidentiary and instructional challenges,” their lawyers wrote. “But with more than 20,000 similar cases now pending before the district court, the court should consider alternative grounds for affirmance that would have broader application to the litigation as a whole.”

Those alternative grounds included federal pre-emption since the FDA previously had rejected reference to the laboratory test on Xarelto’s label.

But the FDA’s action was not “clear evidence,” plaintiffs responded this month, citing the 2017 decision by the U.S. Court of Appeals for the Third Circuit that Merck appealed to the Supreme Court.

“The FDA’s past rejection of proposed language on a similar topic does not necessarily constitute ‘clear evidence’ that a change would have been rejected, because, for example, the FDA might have disagreed only with the company’s selected language, or the position the FDA took in the past might not accurately predict the position it would take at a later time,” Longer wrote.