The Zoloft birth defects multidistrict litigation (MDL) against Pfizer stands at over 100 plaintiffs. But after an unfavorable ruling from the judge, plaintiffs asked for a “do-over” with a new expert, and Pfizer is fighting it.

At issue is the experts’ commentary on behalf of plaintiffs’ arguments that Zoloft can cause birth defects, and that Pfizer knew of the risks but didn’t disclose them. The plaintiffs’ experts noted several animal studies that showed Zoloft complications before the drug was brought to market. However, after discovery and a seven-day hearing, the judge excluded the expert testimony and other opinions offered by the experts.

Pennsylvania federal judge Cynthia M. Rufe, who presides over the MDL, concluded that the scientists did not follow accepted research methods, nor did they discuss any human research findings or other possible reasons for the defects.

Pfizer says, “Plaintiffs had a full and fair opportunity to develop and defend their choice of experts. Under well-established case law, plaintiffs cannot hit the reset button and replace their experts at this late stage of the litigation after their causation experts have been stricken.” They added that new witnesses can only be submitted for “good cause,” and that this didn’t exist in this case.

The elimination of human causation opinions from plaintiffs’ experts’ over the course of the hearings is what is driving plaintiffs. They say that preclinical studies and successive published studies confirm the link between Zoloft and birth defects, and that Pfizer knew the potential of Zoloft to cause them.

The Zoloft Birth Defects Lawsuit is In Re: Zoloft (Sertraline Hydrochloride) Products Liability Litigation, Case No 2:12-md-02342, in the U.S. District Court for the Eastern District of Pennsylvania.

What is Zoloft?

Manufactured, distributed, and labeled by Pfizer, Zoloft is the prescription drug sertraline. It is a member of a class of drugs known as “selective serotonin reuptake inhibitors,” or SSRIs. SSRIs impact serotonin levels, and are the first in a class of psychotropic drugs discovered using a process called rational drug design. With rational drug design, a molecule is designed to affect a specific biological target. Being so direct in treatment, many patients have reported suffering fewer emotional swings and physical side effects from SSRIs than from other mood altering medications.

The U.S. Food and Drug Administration (FDA) approved Zoloft in 1991 to treat major depressive disorder (MDD). In the succeeding years, it was approved to treat a number of other depressive and mood disorders, like OCD and PTSD. It was never approved for use in pregnant women.