A federal judge has dismissed the majority of more than 300 lawsuits filed against Pfizer Inc that claim that use of the company's antidepressant Zoloft (sertraline) was linked to birth defects in children whose mothers took the drug during pregnancy.
Although at least one case is still pending following the decision, US District Judge Cynthia Rufe, of the Eastern District of Pennsylvania, dismissed most of the other consolidated cases on Tuesday without a trial, saying the plaintiffs had failed to produce adequate evidence showing a plausible link between the selective serotonin reuptake inhibitor (SSRI) and birth defects.
"The court recognizes that the final scientific verdict as to whether Zoloft can cause birth defects may not be delivered for many years," Rufe writes.
"Nevertheless, plaintiffs chose when to file their cases, and the court concludes that for the plaintiffs who have continued to pursue their claims, the litigation gates must be closed."
Pfizer also prevailed in two previous jury trials last year that involved similar claims from women in Philadelphia and St. Louis. In those trials, the plaintiffs sought at least $2.4 million in damages.
Lawyers for the plaintiffs in those cases argued that Pfizer researchers noted in a core data sheet written before the drug went on the US market in 1991 that women who were not on birth control should not take Zoloft, owing to the risks for congenital defects, but the information never made it into Zoloft's safety label, according to Bloomberg News.
Pfizer has maintained that no studies have proven a link between the drug and birth defects.
"While we have great sympathy for families affected by birth defects, this verdict affirms that the Zoloft label contains adequate, science-based information on the benefits and risks of the medicine," the company said in a statement following the second verdict.
"A range of independent expert organizations, such as the American Psychiatric Association, American College of Obstetricians and Gynecologists, and the American Heart Association, have found that Zoloft's use during pregnancy is not associated with birth defects.
"There is extensive science supporting the safety and efficacy of Zoloft, and the medicine carries accurate, science-based and FDA-approved information on its benefits and risks," the company added.
Pfizer's sales of Zoloft reached approximately $3.3 billion in 2005, according to Bloomberg, making the drug the best-selling antidepressant on the market at the time.
The company has since lost patent protection on the drug, and several generic versions of sertraline are currently on the market.
Zoloft is not the only SSRI to be the subject of litigation over claims of birth defects. Similar allegations were made against GlaxoSmithKline over its antidepressant Paxil (paroxetine). However, the outcome was much different ― the company agreed to pay more than $1 billion to settle more than 800 cases in 2010 Bloomberg reported.
Among conflicting studies over the years regarding congenital defects linked to SSRI use, paroxetine has stood out. In one meta-analysis, a summary estimate indicated that there was a 50% increase in the prevalence of congenital defects associated with use of the drug during the first trimester.
Early results from epidemiologic studies raised enough concern for the FDA to issue a warning of potential congenital cardiac malformations associated with paroxetine use in 2005.
Numerous other studies since then have shown, however, that the risk associated with the use of any SSRIs, including paroxetine, during pregnancy is attenuated after adjustment for confounders.
In one population-based study that included nearly 16,000 singleton births in Finland in which exposure to SSRIs occurred, no increased risk for congenital anomalies was found. In fact, the study showed some protective effects for women who underwent treatment with SSRIs during pregnancy in comparison with women who did not receive SSRIs.
As reported by Medscape Medical News, a recent British study of the use of antidepressants during pregancy included nearly 9000 women treated with SSRIs as well as non-SSRIs, either before or during pregnancy.
No link to cardiac defects was found. The study did show that among women receiving antidepressants during pregnancy, there was a higher prevalence of other risk factors associated with heart disease, including smoking, obesity, and diabetes.
Mark Turrentine, MD, a Houston-based physician who is a member of the American Congress of Obstetricians and Gynecologists Committee on Practice Bulletins–Obstetrics, told Medscape Medical News that the study underscored the need for closer monitoring when pregnant patients are being treated with antidepressants.
"I think the important message the ob/gyn community took away from that study is that these pregnancies potentially represent a higher-risk population," he said.
"So even if the antidepressant medications are not causative of birth defects, the antipsychotic use is associated with other factors, such as smoking, polypharmacy, substance abuse, psychosocial stressors, etc, so those are pregnancies that probably have to be followed closely."
He added that the dismissal of the Zoloft lawsuits is consistent with the current evidence concerning the safety of SSRI use during pregnancy.
"As physicians, we look at the available evidence, and that shows that SSRIs have not been proven to cause birth defects. I think the more important issue is, if you don't treat depression, there is a greater risk to the mother and baby."
In December 2011, the FDA issued guidance on the use of SSRIs in pregnancy. The agency recommended healthcare professionals "not to alter their current clinical practice of treating depression during pregnancy."
Medscape Medical News © 2016 WebMD, LLC
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Cite this: Zoloft Lawsuits Dismissed: No Link to Birth Defects, Says Judge - Medscape - Apr 11, 2016.