Last week, the first of nine Paxil birth defect lawsuits in line for trial in Pennsylvania was dismissed after a judge excluded evidence of the drug’s later heightened FDA warning. Judge Kenneth Powell of the Philadelphia County Court of Common Pleas granted a compulsory nonsuit in favor of defendant GlaxoSmithKline PLC (“GSK”) after portions of the prescribing physician’s testimony were excluded based on the judge’s interpretation of a pretrial decision barring evidence of “subsequent remedial measures” GSK may have taken in connection with its antidepressant, Paxil. The judge found that plaintiffs failed to provide admissible testimony that the prescribing physician would have changed his treatment decision if he had been provided more information about Paxil and the potential risk of birth defects – a requirement to plaintiffs’ failure to warn claim against GSK.

In 2003, plaintiff Elisabeth Balser took Paxil during the first trimester of her pregnancy. Her son, Braden Rader (also named in the lawsuit), was later born with a combination of several congenital heart defects. In September 2005, under FDA guidelines, Paxil was reclassified as a Pregnancy Category D medication, which warns that studies in pregnant women demonstrated a risk to fetuses. In the discovery phase, Balser’s prescribing physician – Dr. Robert Kiehn – testified at his deposition that he would never have prescribed the drug if it carried the FDA’s Pregnancy Category D designation. GSK successfully moved to exclude these portions of Dr. Kiehn’s testimony from trial as evidence of GSK’s “subsequent remedial measures” in connection with Paxil barred by the judge’s pretrial order.

After plaintiffs rested their case, GSK moved for nonsuit on the grounds that plaintiffs had not proved causation. Judge Powell, in granting GSK’s motion, noted: “It is not reasonable to infer based on the testimony that was presented that Dr. Kiehn would not have prescribed Paxil had he known the additional risk. Based on the testimony presented by the plaintiff[s], all the jury could do is guess. I cannot permit the jury to speculate as to causation.”

Plaintiffs have expressed their plan to file a motion for a new trial and, if necessary, an appeal to the Superior Court on the basis that the judge improperly excluded key portions of Dr. Kiehn’s testimony, which they will argue should have been admitted at least for the limited purpose of proving causation. But according to Judge Powell, Balser’s attorneys “could have asked admissible questions of what Dr. Kiehn would have done had he known Paxil was a potential teratogen or that it caused embryo-fetal death, but they did not do so.” Instead, their questions related to Paxil’s inadmissible Category D label.

Judge Powell’s complete exclusion of evidence of Paxil’s later heightened warning (and subsequent dismissal of the lawsuit) has favorable implications for manufacturers similarly defending failure to warn claims in mass tort programs where subsequent warnings are at play, at least at the trial stage. At a minimum, the parties’ counsel may take additional care in crafting their deposition questions to prescribing physicians as the reach of a pretrial motion excluding certain types of evidence from the jury could largely depend on it.