Pfizer Weighing FDA Request to Change Zoloft's Warnings

  • FDA suggests altering warnings on congenital cardiac defects
  • Pfizer faces hundreds of lawsuits over the antidepressant

The U.S. Food and Drug Administration wants Pfizer Inc. to modify safety warnings for its antidepressant Zoloft and acknowledge for the first time that some studies linked the mood-altering medication to heart defects in newborns. The body of evidence on the drug still finds no tie to birth defects.

The FDA asked Pfizer in August to alter Zoloft’s warnings to show some researchers have found an “increased risk of congenital cardiac defects” in babies whose mothers took the drug, according to court papers filed earlier this month.

The request was part of a widespread initiative by the FDA to reformat drug labels across the industry, Pfizer said in an e-mailed statement.

“The new language, which is still in draft form, reflects the extensive science supporting the safety and efficacy of Zoloft, stating a complete review of the scientific evidence finds that there is no difference in birth defect risks between pregnant women who took Zoloft and those who did not," Pfizer said.

Pfizer is fighting lawsuits by hundreds of women who say they weren’t adequately warned the drug could cause defects in their newborns. While some legal experts say the label change could help the company fend off future lawsuits, it could also help bolster claims by those who have already sued over Zoloft, once the most prescribed antidepressant in the U.S.

“Since the FDA is basically forcing them to acknowledge the existence of credible studies showing Zoloft may cause heart defects, a jury could conclude they were ignoring or hiding those links to sell more of their product,” said Erik Gordon, a University of Michigan law professor, who teaches classes about how drugs are developed and regulated.

‘No Difference’

Regulators also noted in their suggestions that the vast majority of Zoloft’s research found “no difference in major birth defect risk” for users of the medication, according to the filings. Zoloft’s current label says there are “no adequate and well-controlled” studies of pregnant women.

Pfizer’s lawyers revealed the suggested changes in a federal court hearing on Sept. 1 in Philadelphia. The company maintains that the medication doesn’t cause heart defects and that it properly warned women and their doctors about the drug’s risks.

Earlier this year, Pfizer officials persuaded juries in St. Louis and Philadelphia that its current label explicitly urged doctors to examine the drug’s risks before prescribing it to pregnant women. Both state-court panels ruled for the company in the only two Zoloft cases that have gone to trial. The first federal trial is scheduled for January.

Zoloft Sales

Sandy Walsh, an FDA spokeswoman, declined to comment on the reasons behind the agency’s request, saying in an e-mail that “any conversations about labeling are confidential.” The company would have to provide details, she said.

New York-based Pfizer reaped about $3.3 billion in Zoloft sales in 2005, making it the best-selling antidepressant on the market. The company lost patent protection on the drug the next year and generic versions are now made by other drugmakers, including Mylan NV. Under U.S. law, the label on generic versions of the drug must contain the same warnings as Pfizer’s label.

While the label change may help former Zoloft users suing Pfizer, it also will allow the company to better fend off future lawsuits, said Carl Tobias, who teaches product-liability law at the University of Richmond.

“It puts a fence around the number of future cases that can be brought accusing Pfizer of failing to warn about heart defects,” Tobias said. “It gives the company some certainty about its overall exposure.”

Mark Cheffo, a lawyer for Pfizer, told U.S. District Judge Cynthia Rufe at the Sept. 1 hearing that the company began reexamining Zoloft’s label at the FDA’s request in 2014.

Pfizer Review

Francesca Kolitsopoulos, an associate director in Pfizer’s Worldwide Safety Strategy unit who handled the review, found studies showing an association between the medicine and “cardiac malformations, which could be causal,” according to court filings.

In an April 7, 2014, e-mail, Kolitsopoulos warned Pfizer officials that updating Zoloft’s label “may be warranted for the risk of cardiac malformations,” including septal defects, according to court documents.

The FDA’s suggested additions to the warnings include references to studies about the link between Zoloft and septal defects, a condition where a hole develops in the heart at birth.

Kolitsopoulos ultimately found the studies were inconclusive, Cheffo told Rufe, according to a transcript of the hearing.

“Overall, a causal relationship has not been established,” he said. “That’s Pfizer’s position then and now.”

The case is In Re: Zoloft Products Liability Litigation, 12-md-02342, U.S. District Court, Eastern District of Pennsylvania (Philadelphia).

(Corrects number of lawsuits in fifth paragraph, removes graphic, adds context in first paragraph.)
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