GlaxoSmithKline scores a big win in Zofran litigation after FDA repeatedly rejects pregnancy warning

A judge just upended years of litigation against GlaxoSmithKline and its Zofran drug only months before a key trial was set to begin this fall. 

GSK has been defending against claims that Zofran, a nausea drug, can cause birth defects if used during pregnancy and that the company failed to warn about the risks.

But because GSK and Novartis, which bought Zofran rights in 2015, submitted safety data to the FDA several times over the years—and the FDA decided against adding a pregnancy warning each time—the plaintiffs' state-law claims are preempted by federal law, a judge ruled Tuesday. 

Judge F. Dennis Saylor's ruling comes just weeks after the FDA refused Novartis' request to add the pregnancy risks to Zofran's label. It's an important win for GSK and a reversal from a 2019 ruling that federal preemption didn't apply.

The plaintiffs are hundreds of women or their children who alleged GSK marketed Zofran off-label to prevent nausea and vomiting from pregnancy. The drug scored FDA approval in 1991 to prevent nausea and vomiting from chemotherapy or after surgery and has never been approved to prevent morning sickness, Saylor wrote in his Tuesday order. 

Because the plaintiffs are suing the drugmaker under state law, claiming the company failed to warn them about the risks of using Zofran during pregnancy, their arguments are undermined by the FDA’s decision against adding the warning, Saylor wrote. 

RELATED: Supreme Court puts Merck's FDA preemption argument up for another review 

And the FDA has considered all the data on Zofran's risks very recently, Saylor pointed out. Novartis asked the FDA last year to add the warning, and at that point the FDA had "every study and piece of scientific literature on which plaintiffs rely" for their lawsuits, the judge wrote.

The FDA refused that request in April.

"In short, there is 'clear evidence' that the FDA would not approve changing the Zofran label to include the warning that plaintiffs contend is required by state law," the judge wrote.

As of January, GSK said it faced around 430 lawsuits in the Zofran multidistrict litigation. The first bellwether trial had been set for mid-October. 

RELATED: 'Skinny labeling' under fire: GSK, Teva federal court decision undermines common practice 

The issue of whether the FDA's labeling decisions preempt state law claims has hung over the pharma industry for years. In 2019, Merck took its Fosamax arguments all the way to the Supreme Court. But even after considering that case, the court’s ruling didn’t provide the “degree of clarity that many observers had hoped for,” the American Bar Association said at the time.