The fate of the Tylenol autism class action will turn on the outcome of the upcoming Daubert challenges in which each side objects to the admissibility of the other side’s expert witnesses on the issue of causation. If Judge Cote excludes the plaintiffs’ causation experts because their scientific opinions are unreliable, it will mean the end of the Tylenol autism lawsuits (at least in federal courts). Conversely, it will be game on if she finds that the plaintiffs’ experts are admissible.
Plaintiffs Seek to Exclude Defense Experts
This week, both the plaintiffs filed their objections to the defense experts, and the defendants filed their own objections to the scientists retained by the plaintiffs. This post will summarize the plaintiffs’ Daubert objections for each defense expert.
There is no way around the fact that plaintiffs are on the defensive in a Daubert hearing. Plaintiffs can lose everything if the hearing goes south. But the best defense is a good offense. And if you read these motions, you will see plaintiffs’ Acetaminophen lawyers have a lot of firepower to work to make this hearing a referendum on the defense experts, too.
Plaintiffs’ Motion to Exclude Defense Expert Dr. Craig M. Powell
One of the defense experts is Dr. Craig M. Powell, MD, PhD. Dr. Powell is a neurobiologist and Chair of the Department of Neurobiology at the University of Alabama at Birmingham School of Medicine. Dr. Powell’s research focuses on autism, intellectual disability, and cognitive dysfunction.
Dr. Powell’s primary role as an expert witness for the defense in the Tylenol autism litigation is what we would call an “expert naysayer.” Dr. Powell’s opinions in this litigation essentially seek to dismiss the plaintiffs’ causation evidence as “speculative.” He even accuses the plaintiffs’ experts (which include some of the leading experts in the world) of “the misuse of science.”
The plaintiffs object to Dr. Powell’s opinions because his “exclusionary approach does not reliably account for the vast majority of preclinical evidence that conflicts with his conclusions[.].” The plaintiffs argue that Dr. Powell’s methodology to dismiss 94 of 97 studies linking Tylenol to autism is unclear and inconsistent, suggesting that his only aim was to find ways to dismiss evidence.
Plaintiffs’ Motion to Exclude Defense Expert Dr. Jennifer Pinto-Martin
Dr. Jennifer Pinto-Martin, PhD, MPH, is an epidemiologist and Professor at the University of Pennsylvania School of Nursing. Dr. Pinto-Martin is also the director of the Pennsylvania Center for Autism and Developmental Disabilities Research and Epidemiology, a CDC-funded research center.
The plaintiffs contend that Dr. Pinto-Martin’s expert opinions in the litigation are so overly conservative that her interpretation of any epidemiological evidence would almost be guaranteed never to find any link or causation between anything. The plaintiff points out the overwhelming weight of studies showing a connection between using acetaminophen during pregnancy and higher rates of autism. The claim that Dr. Pinto-Martin goes so far as to dismiss this that she turns “science into a Catch-22.”
Among other things, Dr. Pinto-Martin contends that observational studies can never be sufficient to prove causation despite her entire field of epidemiology being based on precisely the opposite principle. The plaintiffs also note that Dr. Pinto-Martin admits that no pregnant woman would even agree to participate in a study because of the alarming observational evidence suggesting a link between autism and Tylenol during pregnancy.
In fact, Dr. Pinto-Martin actually said it would be “unethical” to ask a pregnant woman to take acetaminophen because she says there are so many “studies suggesting a risk” of autism. Yet, somehow, she simultaneously claims that there is no link between acetaminophen use during pregnancy and autism.
Plaintiffs’ Motion to Exclude Defense Expert Dr. Alexander Kolevzon
Defense expert Dr. Alexander Kolevzon, MD, is a child psychiatrist and a Professor at the Icahn School of Medicine at Mount Sinai. His research efforts focus on understanding the neurobiology of autism and related disorders.
The plaintiffs severely discredited Dr. Kolevzon right from the start by disclosing that before becoming an expert for the defense, he consulted with a plaintiffs’ attorney and agreed to be a plaintiff witness for $600 per hour. But then the defendants offered him $650 per hour, so he switched sides and became an expert for the defense.
The Motion to Exclude also notes that Dr. Kolevzon co-authored a chapter in a book in which he identified “prenatal use of acetaminophen” as a potential risk factor for autism. Promptly after switching sides, Dr. Kolevzon disavowed the book, then somehow forgot to include the book on his list of publications produced in discovery.
Finally, the plaintiffs’ Motion to Exclude attacks on the reliability of Dr. Kolevzon’s opinions, which he sold to the highest bidder. The plaintiffs contend that his opinions lack reliability because they are not based on a clear methodology and fail to consider all relevant evidence.
Plaintiffs’ Motion to Exclude Defense Expert Dr. Mary D’Alton
Dr. Mary D’Alton, MD, is an OB/GYN and Chair of the Department of Obstetrics & Gynecology and the Willard C. Rappleye Professor of Obstetrics & Gynecology at Columbia University Irving Medical Center.
According to the plaintiffs, Dr. D’Alton’s only opinions in this case are that acetaminophen as “safe” and that the plaintiffs bringing these lawsuits are merchants of misinformation. The plaintiffs question whether Dr. D’Alton’s opinions have any relevance to the issue of causation in the first place.
The plaintiffs assert that Dr. D’Alton, as an OB/GYN, lacks the necessary training and expertise to opine on the causal association between acetaminophen and neurodevelopmental disorders like autism. They also argue that her opinions should not be admissible because they do not relate to causation.
Plaintiffs’ Motion to Exclude Defense Expert Dr. Wendy Chung
Dr. Wendy Chung, MD, PhD, is a molecular geneticist and defense expert. The plaintiffs attack Dr. Chung because outside of the litigation, she regularly gives TED talks and publishes articles acknowledging that autism can result from drugs taken by mothers during pregnancy.
The plaintiffs’ Daubert challenges to the admissibility of Dr. Chung’s opinions start with the assertion that she fails to identify any specific methodology she used to reach her conclusions, insisting instead that they were “obvious.” According to the plaintiffs, that is a fatal flaw because it prevents the court from evaluating the reliability of her conclusions under the Daubert standards.
Second, the plaintiffs argue that Dr. Chung’s opinions in this litigation are based on a fundamental scientific error involving the concept of heritability:
Her opinion that ASD and ADHD are predominantly inherited, that is, genetic, stems from statistics showing that ASD and ADHD are highly heritable. Heritability, however, measures the source of a trait’s variance in a population, not the cause of its development in an individual. Height is roughly as heritable as Dr. Chung contends ASD and ADHD are (80–90%). But no informed scientist would therefore conclude that all 6-foot-tall people in a population owe approximately 58 to 64 of their vertical inches to genes. Other causal factors, namely environmental exposures, are at play. Dr. Chung freely admits as much when it comes to ASD—just not in her report for this case.
Plf. Motion to Exclude Dr. Chung at p. 2.
What All This Means in the Scheme of Things
The motion to exclude experts are legal request made by one party in a lawsuit to ask the court to prevent the other party from presenting expert testimony or evidence from a particular expert witness during trial. This motion is named after the Daubert standard, which is a legal framework Judge Cote will use to determine the admissibility of expert testimony and whether Tylenol lawsuits in federal court can proceed to a jury.
The purpose of such a motion is to challenge the qualifications, methodology, relevance, or reliability of the expert’s testimony or evidence. The moving party argues that the expert’s testimony should be excluded because it fails to meet the necessary legal standards for admissibility.
In the context of a Daubert motion, the court evaluates several factors to determine whether the expert’s testimony should be allowed, including:
- Qualifications: Whether the expert has the necessary education, training, and experience to provide expert opinions in the relevant field.
- Methodology: Whether the expert’s methods and principles are scientifically valid and reliable.
- Relevance: Whether the expert’s testimony is relevant to the issues in the case.
- Peer Review: Whether the expert’s work has been subject to peer review and publication.
- Error Rate: Whether the expert’s methods and conclusions have a low error rate.
- General Acceptance: Whether the expert’s methodology is generally accepted within the relevant scientific or professional community.
If the court grants the motion to exclude the expert, that expert’s testimony and evidence will not be allowed at trial. In this case, there is a second purpose: discredit the other side’s experts for the Daubert hearings, regardless of whether the witnesses are excluded.
Honestly, it is surprising that will all the money thrown into the defense of this litigation the defendants could not produce a stronger expert lineup. But it speaks to how strong the plaintiffs’ scientific evidence is in this case.
Daubert Hearings and Legal Expert Testimony
Daubert hearings, stemming from the U.S. Supreme Court case Daubert v. Merrell Dow Pharmaceuticals our lawyers have talked about a great deal elsewhere in this litigation, play a pivotal role in legal proceedings where expert witnesses are called upon to provide testimony about causation like have in the acetaminophen litigation. These hearings serve as a gatekeeping mechanism, ensuring that expert testimony meets specific criteria for admissibility, including the requirement that the expert’s testimony is founded on reliable scientific principles and methods.
So expert witnesses often offer professional opinions regarding whether a particular exposure or action caused harm to the plaintiff. The Bradford Hill analysis can be particularly relevant in these situations. During the Daubert hearings, acetaminophen experts may employ the Bradford Hill criteria to assess and present evidence that substantiates a causal link between the exposure or action and the harm suffered by the plaintiff.
By demonstrating the strength of the association, consistency of findings, temporal relationship, and other pertinent factors, experts can make a compelling case for the admissibility of their expert testimony.
What Is Bradford Hill?
If you read the Daubert motions in the Tylenol lawsuits, you will hear a lot about Bradford Hill. What is that?
The Bradford Hill analysis, named after British epidemiologist Sir Austin Bradford Hill, serves as a structured framework within epidemiology to evaluate the strength of evidence supporting a causal relationship between an exposure (such as a drug, environmental factor, or behavior) and a specific health outcome (like a disease or adverse condition). To ascertain causation, researchers and experts rely on a set of criteria known as the Bradford Hill criteria.
What Is the Bradford Hill Criteria?
The Bradford Hill criteria, also known as Hill’s criteria for causation, are a set of nine principles or guidelines used in epidemiology and medical research to assess whether a causal relationship exists between an exposure, like the exposure to acetaminophen, and a particular outcome (like ASD or ADHD).
Here are the nine Bradford Hill criteria:
- Strength of Association: This criterion considers the magnitude of the association between the exposure and the outcome. A stronger association is more suggestive of a causal relationship.
- Consistency: Consistency relates to the reproducibility of findings across different studies, populations, and settings. If multiple studies consistently show a similar association, it strengthens the case for causation.
- Specificity: Specificity involves the idea that a particular exposure should lead to a specific outcome. While not always applicable, when a specific exposure consistently leads to a specific outcome, it supports causation.
- Temporality: Temporality refers to the temporal sequence of events, where the exposure precedes the outcome. Establishing a clear timeline between exposure and outcome is essential for causation.
- Biological Gradient (Dose-Response Relationship): This criterion looks at whether there’s a dose-response relationship, meaning that as the dose or level of exposure increases, the likelihood or severity of the outcome also increases. A dose-response relationship strengthens the evidence for causation.
- Plausibility: Plausibility assesses whether there’s a plausible biological or physiological mechanism that can explain how the exposure leads to the outcome. A plausible mechanism supports the case for causation.
- Coherence: Coherence involves examining whether the causal hypothesis is consistent with existing knowledge and scientific understanding. A coherent explanation is more likely to support causation.
- Experiment: While not always feasible in epidemiological studies, experimental evidence from controlled trials can provide strong support for causation when it demonstrates that modifying the exposure affects the outcome.
- Analogy: This criterion involves drawing comparisons between the situation under investigation and similar situations where causation has already been established. Analogies can provide additional support for causation.