Cherry-Picking Epidemiological Data Proves Fruitless For Zantac MDL Plaintiffs

• Jurisdiction: United States,Federal
• Author: Rand Brothers, Michael L. Lavetter and Spencer W. Churchill
• Law Firm: Winston & Strawn LLP
• Published date: 22 March 2023

The plaintiffs in the Zantac MDL faced a challenge that is common in products liability cases: How to handle evolving science and conflicting epidemiological data. Predictably, the plaintiffs hired experts to weave favorable epidemiological data into opinions supporting their allegation that Zantac, a heartburn medication also known as ranitidine, had the potential to degrade into a known carcinogen, NDMA. But when the U.S. District Court for the Southern District of Florida found that these experts had not adequately addressed countervailing epidemiological data'among other shortcomings, as detailed in our recent posts on other aspects of the Zantac decision'it excluded their opinions and granted summary judgment against the more-than-2,450 plaintiffs because they had no admissible evidence of general causation.¹ The Court's thorough and well-reasoned analysis illustrates that, while cherry-picking data may seem to give plaintiffs an advantage in the short term, it can ultimately open a path to summary judgment for watchful defendants in pharmaceutical cases.

At the forefront of the Court's analysis was an appreciation of the evolving state of the science during the litigation. The initial complaints in the Zantac litigation relied heavily on scientific data from a testing laboratory's citizen petition.² But the Court noted that FDA later found the testing underpinning the petition to be invalid.³ For instance, a study overseen by Stanford University and initially relied on heavily by the plaintiffs was subsequently retracted by its...