Subject: Causation

Plaintiffs’ Second Bite at the General Causation Apple Fares No Better Than the First in Acetaminophen MDL

Share

In December 2023, back when the ink was still drying on the amendments to Federal Rule of Evidence 702, the Southern District of New York excluded all five general causation experts proffered by plaintiffs in the In re Acetaminophen MDL whose cases had been selected for trial.  We discussed that impressively detailed and painstaking decision here. Observing that all 50 states require proof of general causation in product liability cases and that the plaintiffs now had no experts to carry that water, the court instituted an order to show cause process that led to the dismissal of approximately 550 cases. However, over the defendants’ objections, the court permitted a small handful of new arrivals to the MDL to name their own general causation expert and try again. In yet another impressively meticulous opinion, the court recently doubled down on its Rule 702 “gatekeeping” role and excluded the new plaintiffs’ backup general causation expert in In re Acetaminophen – ASD-ADHD Prod. Liab. Litig., No. 22MC3043 (DLC), 2024 WL 3357608 (S.D.N.Y. July 10, 2024).

The plaintiffs in In re Acetaminophen allege that prenatal use of acetaminophen caused attention deficit hyperactivity disorder (ADHD) and/or autism spectrum disorder (ASD) in offspring. The plaintiffs’ first five proffered general causation experts were excluded in part because the court took issue with the experts’ “transdiagnostic” approach — combining literature of ADHD and ASD into a single analysis — because it merely “obscured limitations in the scientific literature.”   The new plaintiffs’ expert — number six overall — sidestepped the “transdiagnostic” issues and sought to opine solely on a supposed link between prenatal acetaminophen use and ADHD.  But the court, still mindful of acetaminophen’s critical role as the only pain reliever and fever reducer indicated for use during pregnancy and the FDA’s multiple reviews of its safety, remained vigilant in its Rule 702 obligation.

Continue reading “Plaintiffs’ Second Bite at the General Causation Apple Fares No Better Than the First in Acetaminophen MDL”

California Supreme Court Walks Middle Ground on Warnings Causation but Reaffirms Learned Intermediary Doctrine in Himes

Share

As we reported in April, the United States Court of Appeals for the Ninth Circuit certified a question on California’s Learned Intermediary Doctrine in Himes v. Somatics, LLC, 2022 WL 989469 (9th Cir. Apr. 1, 2022). The California Supreme Court has now decided the issue in a way that walks the middle ground. On the one hand, the court rejected plaintiff’s call for recognizing an exception to the learned intermediary rule and reaffirmed the basic rule that a manufacturer’s duty to warn runs to the prescribing physician. On the other hand, the court ultimately lowered plaintiff’s burden of providing warnings causation. The opinion has clear ramifications not only on dispositive motion and trial practice, but on discovery strategies in prescription drug and medical device cases.

The question before the court was whether a plaintiff is “required to show that a stronger risk warning would have altered the physician’s decision to prescribe the product,” or whether a plaintiff may instead establish causation “by showing that the physician would have communicated the stronger risk warning[ ] to the plaintiff, either in their patient consent disclosures or otherwise, and a prudent person in the patient’s position would have declined the treatment after receiving the stronger risk warning.” (Himes v. Somatics, LLC, 16 Cal.5th 209 (2024).)

Continue reading “California Supreme Court Walks Middle Ground on Warnings Causation but Reaffirms Learned Intermediary Doctrine in Himes“

Peer Review Can’t Save “Junk Science” from FRE 702 Judicial Gatekeeping – In re: Roundup Court Excludes Expert Whose Opinions Had Been Published in Peer-Reviewed Literature

Share

When tasked with assessing the admissibility of expert testimony under Federal Rule of Evidence 702, courts often cite the so-called Daubert factors as criteria that guide the inquiry.  Among those factors is “whether the [expert’s] theory or technique has been subjected to peer review and publication.”  Daubert v. Merrell Dow Pharms., Inc., 509 U.S. 579 (1993).  The Daubert Court observed that, although publication “is not a sine qua non of admissibility,” peer review “increases the likelihood that substantive flaws in methodology will be detected.”  But peer review is not coterminous with the Rule 702 inquiry that federal courts are called upon to make, especially with the rise of so-called predatory publishing and journals with relaxed (or absent) peer review processes.  As one court recently observed, “a court can’t wave junk science through the Daubert gate simply because it survived some prepublication peer-review process.”  In re: Roundup Products Liability Litigation, 2024 WL 3074376 (N.D. Cal. June 20, 2024).

In In re: Roundup, the plaintiff claimed to have developed non-Hodgkin’s lymphoma (NHL) as a result of using the defendant’s herbicide.  In support of that claim, he offered a single expert on the issue of whether glyphosate, the active ingredient in the herbicide, can cause NHL in humans.  The expert’s opinions were all contained in two peer-reviewed and published articles that the expert had co-authored.  But only one of the two—a 2019 meta-analysis of six epidemiological studies addressing the link between glyphosate and NHL, which had been published before the expert became involved in the litigation—grappled with the available epidemiological evidence.  The defendant attacked that paper on multiple grounds, and the court agreed that it constituted “junk science” with several flaws each independently justifying its exclusion.

Continue reading “Peer Review Can’t Save “Junk Science” from FRE 702 Judicial Gatekeeping – In re: Roundup Court Excludes Expert Whose Opinions Had Been Published in Peer-Reviewed Literature”

Northern District of Illinois Holds that Seventh Circuit Precedent is Incompatible with Rule 702 as Amended

Share

In explaining the December 2023 amendments to Federal Rule of Evidence 702, the Advisory Committee called out several ways in which “many courts” had “incorrectly” applied Rule 702 and failed to adequately discharge their duty as gatekeepers with regard to expert witness testimony.  The import of those comments is that existing precedent on Rule 702 may be “incorrect” and must be re-examined.

A case pending in the Northern District of Illinois serves as a fine illustration of how this re-examination should work in practice.  In West v. Home Depot U.S.A., Inc., 2024 WL 1834112 (N.D. Ill. Apr. 26, 2024), the plaintiff alleged that she was injured when portions of a store display fell on her.  She offered a trio of experts to opine that her claimed injuries had been caused by the incident, but none of them “were aware of, let alone reviewed, [her] highly salient medical history prior to issuing their causation opinions.”  Rather, they were treating physicians who based their opinions solely on their post-incident treatment of the plaintiff.

Continue reading “Northern District of Illinois Holds that Seventh Circuit Precedent is Incompatible with Rule 702 as Amended”

Expert’s Results-Driven Methodology Leads to Exclusion and Summary Judgment in Paraquat MDL

Share

An expert witness is not supposed to pick a desired result and then reverse engineer inputs and methods that reach that result.  As the Ninth Circuit observed 30 years ago, “[c]oming to a firm conclusion first and then doing research to support it is the antithesis of [the scientific] method.”  Claar v. Burlington Northern R.R. Co., 29 F.3d 499, 502-03 (9th Cir. 1994).  A recent opinion from the Southern District of Illinois offers a fine example of an expert with a results-driven approach and a court that called him out on it.

In re Paraquat Products Liability Litigation, 2024 WL 1659687 (S.D. Ill. Apr. 17, 2024), arises from a multidistrict litigation (“MDL”) in which the plaintiffs claim to have developed Parkinson’s disease as a result of exposure to an herbicide, paraquat.  Four plaintiffs whose cases had been chosen for the MDL’s first trials offered a statistician (the parties disputed whether he also qualified as an epidemiologist) as their sole expert to establish general causation.  He had a difficult task, as no peer-reviewed literature established a link between paraquat exposure and Parkinson’s disease.  Indeed, when the court asked the plaintiffs to identify such literature, the plaintiffs could cite only a single opinion article.  That article had been shared with another of the plaintiffs’ experts before it was published, leading the court to conclude in deciding a prior discovery dispute that there was reason to investigate “whether counsel for the MDL plaintiffs, their experts, or other third parties may have influenced the contents of the article for the benefit of one side in the MDL.”  2023 WL 8372819 (S.D. Ill. Dec. 4, 2023).

Continue reading “Expert’s Results-Driven Methodology Leads to Exclusion and Summary Judgment in Paraquat MDL”

EU Reaches Legislative Deal on Proposed ‘Digital Age’ Updates to Product Liability Directive

Share

Last week, the European Union made a significant breakthrough towards its goal of overhauling the 40-year-old Product Liability Directive for the demands of the “digital” age and modern economy. To amend the directive, the elected European Parliament and the European Council (comprised of government representatives of the 28 member states) must agree on final language and separately pass the draft legislation through their respective bodies. After extensive legislative efforts and negotiations, the European Council (currently led by the Government of Spain) and the European Parliament issued press releases announcing that they have reached a political agreement regarding the proposed updates to the directive.

Continue reading “EU Reaches Legislative Deal on Proposed ‘Digital Age’ Updates to Product Liability Directive”