A couple of weeks ago, we reported on the terrific Daubert decision in the Mirena IIH MDL in the Southern District of New York, In re Mirena IUS Levonorgestrel-Related Prods. Liab. Litig., 2018 WL 5276431 (S.D.N.Y. Oct. 24, 2018), in which the court granted the defendants’ motions to dismiss all seven of the plaintiffs’ remaining general causation experts.  In that post, we explained that all seven opined that the defendants’ intrauterine contraceptive device caused idiopathic intracranial hypertension (“IIH”), a rare and potentially serious condition market by increased cerebrospinal pressure in the skull.  Only one study had ever found a causal link between Mirena and IIH.  That study was by Dr. Mahyar Etminan, who was on the plaintiffs’ payroll at the time he published the study, a fact he failed to disclose.  After a prominent scientist in the field attacked the methodology of the Etminan study because it failed to control for age and gender, Dr. Etminan repudiated much of the study’s analysis and withdrew as an expert.

Of the seven remaining experts, four drew their general causation conclusions largely by drawing on existing sources, including varying combinations of case reports regarding Mirena, case reports regarding other contraceptive products containing LNG, another product’s warning label, the repudiated portions of the Etminan study, and another study (the “Valenzuela study”) that reported a statistically significant association between LNG-containing devices and IIH but which, the authors emphasized, found only a correlation, not a causal link.  The other three experts were “mechanism” experts, each of whom postulated a supposed mechanism by which the defendant’s product could cause IIH.   In our last post, we reported on the court’s decisions regarding two of the experts in the first group but we promised to tell you more.  Today, we focus on one more expert in that group as well as highlights of the court’s decisions about the “mechanism” experts.

The former, the plaintiffs’ ophthalmology expert, was the only one of the plaintiffs’ experts who had written about the relationship between levonorgestrel (“LNG”), the synthetic hormone in  the defendants’ contraceptive device, and IIH, and was the only one of the plaintiffs’ experts who had written an expert report on the supposed causal  link before the MDL was formed.      In a 2015 book about drug-induced ocular side effects, the expert had stated that he believed there was a “possible,” but not a “probable,” association between LNG and IIH.  In the book, he explained that he assessed causation as possible “when there is a temporal relationship, but the association could also be explained by concurrent disease or other drugs or chemicals,” and dechallenge data (information about what happens when the treatment is withdrawn) is “lacking or unclear.”  Mirena, 2018 WL 5276431 at *47 (citation omitted).   In contrast, causation is “probable” or “likely” when “there is a temporal relationship unlikely to be attributed to a concurrent disease or drugs” and there is positive dechallenge data.  Id.   The book’s conclusion that there was a “possible” causal association between LNG and IIH was based largely on case reports involving the defendants’ product and other LNG-containing products and upon two publications discussing several of those case reports.  The book did not consider the Etminan and Valenzuela studies, which had not yet been published.

Unlike the other experts in the first group, the ophthalmologist did not claim to have performed a Bradford Hill analysis.  Instead, in support of the expert’s causation conclusion, his report cited case reports, discussion of another LNG-containing product, case reports, and citations to both the Etminan and Valenzuela studies.  In addition, the report included a vague discussion of broad propositions from which he suggested that there was a biological mechanism for LNG to cause IIH.  In his deposition, however, he repudiated this “mechanism” opinion, testifying that the mechanism was “unknown” and that he was not being offered as a “mechanism” expert.

Analyzing the expert’s opinion, the court stated, “[The] proposed testimony amounts to a blend of disparate items that [the expert] contents together show that Mirena causes IIH. . . . [The expert] does not purport to use the flexible Bradford Hill methodology to guide his analysis.”  Instead, he used a “non-replicable mode of analysis” consisting of “listing factors that he argues support his conclusion.”  Id. at *50.   The court held that the expert’s proposed testimony “fails to meet any of the Daubert reliability factors.”   The expert’s causation conclusion “has not been tested; it has not been subject to peer review; it has no known error rate and there are no standards controlling its operation; and it has not been generally accepted by the scientific community.”  Moreover, the expert’s “handling of virtually every one of the individual items on which he relies” was “methodologically suspect.”  Id.   This included overlooking the fatal flaws in the Etminan study, the expert’s failure “to engage with consequential evidence contrary to his outcome.”   Id.  at *51-52.  Finally, though the expert “[made] his mechanism opinion an important component of his expert report,” he “repeatedly distanced himself” from that opinion at his deposition, “repudiate[ing] any mechanism opinion as beyond his expertise.”  The court held, “”The removal of that pillar alone is fatal to [the expert’s] weight of the evidence analysis;” moreover, the “mechanism” opinion would have been inadmissible in any event because the expert was not qualified to offer it.  Id. at *52.   And so, holding that the expert’s opinions failed to satisfy Daubert’s reliability standards, the court excluded the opinions in their entirety.

The plaintiffs’ “mechanism” experts fared no better.  One, an OB/GYN and the founder of a clinical and epidemiological research organization devoted to reproductive health issues, “embrace[d] the ‘androgen theory’ by which Mirena purportedly causes IIH—specifically that androgens cause IIH and that because LNG, while a progestin, has androgenic effects, LNG in turn may cause  IIH.”  Id.  at *53.  The court held, “As a threshold consideration, [the] theory that Mirena  causes IIH through androgenic side effects does not satisfy any of the four Daubert reliability factors.”  Id. at *58.   But beyond the flaws in the opinion’s premises, the court “discern[ed] a broader overarching lapse of methodology” affecting the mechanism opinion: the expert’s report did not address the threshold issue of “what IIH is and how this condition comes about.”   Id.  In addition, the court criticized (in extensive and thorough detail that is beyond the capacity of these pages) the expert’s “scant attention to the pharmacokinetic process that must underlie the causal sequence that he postulates” and his “speculative leaps in support of his two central premises:  that androgens can cause IIH, and that LNG, a progestin with androgen receptor affinity, can cause IIH.”  Id.   The court concluded,

“In the end, while [the expert’s] credentials are sterling, the methodology underlying his opinion in this case is not.  He relies on supposition and attempts to link disconnected studies by others.   And he uses some of his source material for more than it can fairly support.  The result is a hypothesis that may or may not bear up when and if it is ultimately tested, not a reliable expert opinion admissible under the governing standards.  The Court therefore must exclude his testimony.”  Id. at *62.

The court similarly dispatched the plaintiffs’ other two mechanism experts because their methodologies were unsound and their theories failed to satisfy Daubert’s reliability standards.  Both discussions are lengthy and we cannot do justice to them here, but we again recommend that you read the whole opinion when you have time to appreciate its rigor and its unflinching confrontation and dissection of the technicalities underlying all of the experts’ opinions.  Doing justice to Daubert analysis of opinions like these is a monumental task.   All too frequently, and perhaps understandably, courts decline even to try, counting on juries (or, more likely, settlements) to do their work for them.   The Mirena court displayed rare dedication to the principle that the system can work only if courts properly discharge their duties as “gatekeepers.”  We applaud this decision, urge you to read it and cite it, and we hope that more courts will accept similar challenges.  We will keep you posted.