Applying basic scientific principles to exclude an expert’s unfounded and unsupported opinions, the U.S. District Court for the Northern District of California has granted summary judgment to the maker of the antipsychotic medication Abilify on the plaintiff’s failure to warn and negligent design defect claims. Rodman v. Otsuka America Pharmaceutical, Inc., 2020 WL 2525032 (N.D. Cal. May 18, 2020).

In support of her failure to warn claim, the plaintiff relied on the opinion of Laura Plunkett, Ph.D., a pharmacologist and toxicologist.  Dr. Plunkett asserted that Abilify’s label was inadequate because it did not:

• Accurately state the incidence rate of tardive dyskinesia (TD), a serious, sometimes permanent movement disorder
• Warn that TD can occur among patients taking low doses of Abilify
• Include instructions for physicians about how to diagnose TD.

The court rejected Otsuka’s challenge to Dr. Plunkett’s qualifications and then proceeded to address the substance of her opinions.

Although the Abilify label has warned of the risk of TD since Abilify was first marketed, Dr. Plunkett opined that the true incidence rate of TD was higher than the “infrequent” (i.e., 0.1% to 1%) rate set forth in the label. In support, Dr. Plunkett relied on one published retrospective study and data from the FDA’s Adverse Event Reporting System (FAERS). The court concluded that an incidence rate could not be calculated from these data. It explained:

A true incidence rate is one that looks at a pool of Abilify users to identify how many patients developed TD.  The studies Dr. Plunkett cites looked at a pool of those with TD and identified how many of them used Abilify, which does not result in a true incidence rate.

The court further explained that Dr. Plunkett had impermissibly reinterpreted the data in a manner inconsistent with the conclusions of the study researchers. The authors specifically warned that their data were inadequate to calculate an incidence rate of TD. Similarly, the FDA had warned that data from the FAERS database could not be used to determine a specific adverse event’s incidence rate. The court concluded that Dr. Plunkett had “extrapolated conclusions beyond the scope of her sources” and her opinion regarding the incidence rate was unreliable and inadmissible. Consequently, the plaintiff could not establish that the incidence rate set forth in the label was inaccurate and summary judgment on this point was necessary.

Otsuka also challenged  Dr. Plunkett’s opinions that the label should have warned that TD could occur among patients taking low doses of the medication and that it should have included instructions regarding how to screen for TD. The court did not reach these arguments because the prescribing physician testified that he was already aware that Abilify could cause TD at low doses and he had learned in medical school how to screen for TD. Because adding warnings to the Abilify label regarding these issues would not have altered the prescribing physician’s prescribing decision, the plaintiff could not establish the causation element of her failure to warn claim and summary judgment was appropriate.

The plaintiff pointed to three pieces of evidence in support of her negligent design defect claim:

• Testimony from her neurologist that the neurologist typically recommends two specific medications when a patient is discontinuing an antipsychotic
• Testimony from her prescribing physician that if the rate of TD in the Abilify label were higher, he might not have prescribed it
• Plunkett’s opinion that other medications can treat psychotic disorders.

The court explained that none of this evidence demonstrated the existence of a safer alternative to Abilify. Further, even if the plaintiff had evidence of a safer alternative design, she failed to identify any evidence supporting the other elements of a negligent design claim (i.e., that the manufacturer failed to use reasonable care in designing Abilify and that such negligence caused her injuries). Thus, the court granted summary judgment on the plaintiff’s design defect claim, as well.

Rodman is a good example of how courts can require experts to abide by basic scientific principles and honor the boundaries of the materials on which they purport to rely.