DocketNumber: Case No. 3:16-md-2734
Citation Numbers: 299 F. Supp. 3d 1291
Judges: Rodgers
Filed Date: 3/15/2018
Status: Precedential
Modified Date: 10/18/2024
This is a multidistrict product liability action against the manufacturers and marketers of the prescription drug Aripiprazole, more commonly known as Abilify.
Defendants have moved for summary judgment on the issue of general causation-that is, whether Abilify is capable of causing uncontrollable impulses to engage in certain harmful behaviors. See ECF No. 428. Both the motion, see id. , and the response, see ECF No. 463, are supported by expert testimony. Each side challenges the other's experts as unreliable and those motions are also pending.
I. Background
Abilify is an atypical antipsychotic drug developed and manufactured by Defendants Otsuka Pharmaceutical Co., Ltd. and Otsuka America Pharmaceutical, Inc., who jointly market and distribute it in the United States with Defendant Bristol-Myers Squibb Company (collectively, "Defendants"). See Master Complaint, ECF No. 108-1 at 5.
In 2010, the first published reports suggesting a possible link between Abilify and pathological gambling began appearing in the medical literature. More published reports followed, as well as hundreds of informal reports from patients and healthcare professionals to Defendants and the FDA, describing the onset of impulsive gambling and other impulse control disorders in patients treated with Abilify. The scientific community, the FDA, Defendants, and public health agencies worldwide took notice and began examining whether Abilify is linked to impulse control disorders. The research findings and conclusions of these bodies are at the heart of the motions currently pending before this Court.
*1302In 2012, following a safety review of Abilify based on reports of pathological gambling with patients' use of the drug, the European Medicines Agency ("EMA") required Defendants to modify the drug's product label in Europe to include pathological gambling as a possible "post-marketing undesirable effect" of Abilify and to warn of an "increased risk" of pathological gambling in Abilify patients with a prior history of gambling.
A short biochemistry discussion may be helpful at this point.
Dopamine is a neurotransmitter in the central nervous system that is believed to play an integral role in a number of physiological processes, including movement, cognition, emotional stability, and, relevant to this case, reward-motivated behaviors. It acts on five different receptors-D1, D2, D3, D4, and D5-along four major pathways in the brain-the nigrostriatal pathway, the mesocortical pathway, the mesolimbic pathway, the tuberoinfundibular pathway.
Pharmaceutical companies create drugs that can mimic, duplicate, or block the activity of natural, or "endogenous," dopamine in the brain. The effect of a given drug depends on two pharmacological properties that relate to the manner in which the drug interacts with dopamine receptors: affinity and intrinsic activity. Affinity refers to whether and how tightly the drug binds to dopamine receptors. Intrinsic *1304activity refers to the degree to which the drug, once bound, activates dopamine receptors to produce a measurable physiological effect. Based on these properties, drugs that bind to dopamine receptors can act as agonists or antagonists. A full agonist has both high affinity and 100% intrinsic activity, meaning that it binds tightly to dopamine receptors and mimics the activity of dopamine, producing the same level of physiological response that dopamine naturally produces. Antagonists bind to dopamine receptors, but produce no physiological effects; instead, they simply occupy a receptor site, thereby preventing endogenous dopamine from binding to and activating it. A partial agonist binds to dopamine receptors, but produces less of a response than a full agonist. The functional activity of some partial agonists depends on the presence or absence of endogenous dopamine in the surrounding area. Where dopamine concentrations are high, the partial agonist functions as an antagonist (i.e. , functional antagonist), but where dopamine concentration is low, the partial agonist functions as a full agonist (i.e. , functional agonist). In this case, Plaintiffs' position as to how Abilify causes impulse control problems centers on how the drug binds and interacts with two dopamine receptors-D2and D3-to produce physiological effects in the form of impulsive behaviors.
II. Expert Challenges
To establish general causation, Plaintiffs have proffered the testimony of five experts: Dr. Antoine Bechara, Dr. Joseph Glenmullen, Dr. Eric Hollander, Dr. Russell V. Luepker, and Dr. David Madigan. Simply stated, each of Plaintiffs' experts opines that Abilify can cause impulsive behaviors and each presents scientific evidence in support of his conclusion. Defendants challenge the admissibility of Plaintiffs' expert testimony on general causation as unreliable under Federal Rule of Evidence 702 and Daubert v. Merrell Dow Pharmaceuticals, Inc. ,
A. Legal Standard for Expert Testimony
Rule 702, as explained by Daubert and its progeny, governs the admissibility of expert testimony. Rink v. Cheminova, Inc. ,
To meet the qualification requirement, a party must show that its expert has sufficient "knowledge, skill, experience, training, or education to form a reliable opinion about an issue that is before the court." Hendrix ex.Rel. G.P. v. Evenflo Co., Inc. ,
To meet the reliability requirement, an expert's opinion must be based on scientifically valid principles, reasoning, and methodology that are properly applied to the facts at issue. Frazier ,
Finally, to satisfy the helpfulness requirement, expert testimony must be relevant to an issue in the case and offer insights "beyond the understanding and experience of the average citizen." United States v. Rouco ,
When scrutinizing the reliability and relevance of expert testimony, a court must remain mindful of the delicate balance between its role as a gatekeeper and the jury's role as the ultimate factfinder. Frazier ,
*1306B. Reliability of Expert Testimony on General Causation
To prevail in a pharmaceutical products liability case, a plaintiff must establish both general and specific causation through reliable expert testimony.
The Eleventh Circuit has developed an extensive body of Daubert jurisprudence around the reliability of different categories of scientific evidence that may support an expert opinion on general causation. The Eleventh Circuit considers three "primary" methodologies "indispensable" for proving that a drug can cause a specific adverse effect: epidemiological studies, dose-response relationship, and background risk of disease. Chapman ,
In this case, the parties' experts offer various combinations of primary and secondary methodologies in support of their general causation opinions. To frame the Court's analysis of the expert opinions, a brief review of the scientific and legal principles governing the reliability of each methodology follows.
1. Primary Methodologies
a. Epidemiological Studies
The "best evidence of causation in toxic tort actions" is grounded in epidemiology, Rider v. Sandoz Pharmaceuticals Corp. ,
This causation inquiry is guided by nine well-established factors, known in the scientific community as the Bradford Hill factors.
An epidemiological study identifying a statistically significant association between the use of a drug and a particular adverse effect, accompanied by a reliable expert opinion that the association is causal, is "powerful" evidence of general causation. See Rider ,
b. Dose-Response Relationship
Another primary methodology for establishing causation is through evidence of a dose-response relationship, which is a "relationship in which a change in amount, intensity, or duration of exposure to [a drug] is associated with a change-either an increase or decrease-in risk of" adverse effects from that exposure. McClain v. Metabolife Int'l, Inc. ,
c. Background Risk
A reliable methodology also should take into account the background risk for the disease at issue in the case. McClain ,
2. Secondary Methodologies
a. Biological Plausibility
Biological plausibility refers to a credible scientific explanation of the physiological processes or mechanisms by which a drug can cause a particular disease or adverse effect, based on current biological and pharmacological knowledge. See Ref. Man. at 604; see also McClain ,
*1309b. Case Studies and Adverse Event Reports
Case studies document medical observations occurring coincident with the use of a prescription drug either by a single patient (a case report) or a small number of patients (a case series). Rider v. Sandoz Pharmaceuticals Corp. ,
One type of case report is more worthy of consideration in the general causation assessment, however. This report documents a patient's dechallenge and rechallenge events while taking a particular drug. A dechallenge event occurs where a patient's adverse side effects partially or completely disappear once the drug is stopped. Rider ,
Adverse event reports describe medical events that occurred during or after an individual's use of a prescription drug, which are submitted directly to the FDA by patients, healthcare professionals, and drug manufacturers.
*1310McClain ,
c. In vivo and In vitro Studies
Toxicological knowledge often derives from in vivo studies, in which laboratory animals are exposed to a particular drug, with the outcomes monitored and compared to those for an unexposed control group.
These limitations apply with equal force to in vitro studies, which analyze the effects of drugs on human and animal cells, organs, or tissue cultures in a controlled laboratory setting. See Ref. Man. at 639. Observations about a drug's mechanism of action may be more readily gleaned from in vitro studies than from other sources, but the chemical reactions that occur in the artificial environment of a test tube or petri dish may differ from how the drug will react in, and impact, the complex biological system that is the human body. Ref. Man. at 564; Accutane ,
*1311d. Analogous Drugs
In analyzing causation, scientists sometimes draw from existing studies conducted on other drugs in the same class as, or which have a similar chemical structure to, the particular drug at issue in a case. See McClain ,
3. Weight of the Evidence
The preceding sections addressed the extent to which individual categories of scientific evidence may support an expert opinion on general causation in the Eleventh Circuit. In practice, however, many experts form a general causation opinion by weighing an entire body of scientific evidence. This "weight of the evidence" approach to analyzing causation can be considered reliable, provided the expert considers all available evidence carefully and explains how the relative weight of the various pieces of evidence led to his conclusion. See Milward ,
(1) identify an association between an exposure and a disease, (2) consider a range of plausible explanations for the association, (3) rank the rival explanations according to their plausibility, (4) seek additional evidence to separate the more plausible from the less plausible explanations, (5) consider all of the relevant available evidence, and (6) integrate the evidence using professional judgment to come to a conclusion about the best explanation.
Milward ,
C. Reliability of Common Evidence of General Causation
Plaintiffs' experts, each to a greater or lesser extent, rely on much of the same evidence to conclude that Abilify can cause impulsive gambling and other impulse control disorders. The Court addresses the reliability of the common evidence together in this section. In Section II(D), the Court addresses Defendants' expert-specific objections to Drs. Bechara, Glenmullen, Hollander, Luepker, and Madigan.
1. Epidemiological Evidence-The Etminan Study
Three of Plaintiffs' experts-Drs. Glenmullen, Hollander, and Madigan-base their opinions, in part, on an epidemiological study published by Dr. Mahyar Etminan and Dr. Ric M. Procyshyn in February 2017, in which a statistically significant association was found to exist between Abilify and impulse control disorder, and also between Abilify and gambling disorder ("Etminan Study"). See Mahyar Etminan, Risk of Gambling Disorder and Impulse Control Disorder with Aripiprazole, Pramipexole, and Ropinirole , 37 J. CLINICAL PSYCHOPHARMACOLOGY 1 (2017), ECF No. 428-13.
The Etminan Study is an epidemiological case-control study in which the authors analyzed medical and pharmaceutical billing information for over six million individuals, drawn from a large insurance claims database known as LifeLink.
The Etminan Study described the existence and strength of the association found between Abilify, pathological gambling, and impulse control disorder in the random sample from the LifeLink database in terms of "rate ratios," also known as relative risk. Relative risk is simply a comparison of the incidence of a disease in exposed individuals with its incidence in unexposed individuals. See Ref. Man. at 566. A relative risk of 1.0 means there is no difference in risk between the exposed and unexposed groups; in other words, there is no association between exposure to the drug and the disease. See Ref. Man. at 567; see also Allison ,
In this case, the Etminan Study reported a relative risk of 5.23 for pathological gambling in individuals exposed to Abilify as compared to unexposed individuals, with a 95% confidence interval of 1.78-15.38. See Etminan Study, ECF No. 428-13 at 3. This means that the Study predicted that the increased risk of pathological gambling for Abilify patients within any given sample of the entire LifeLink database would likely fall anywhere between 1.78-15.38. Because the lower bound of the confidence interval (1.78) exceeds 1.0, this is statistically significant. The Study also reported a relative risk of 7.71 for impulse control disorder, with a 95% confidence interval of 5.81 and 10.34. This too is statistically significant. Finally, an analysis restricted to patients with bipolar disorder alone yielded a relative risk of 3.38 for pathological gambling in Abilify patients, with a 95% confidence interval of 1.68-8.48, which is also statistically significant. Defendants do not dispute the accuracy of the Etminan Study's relative risk and confidence interval calculations.
Plaintiffs' biostatistician, Dr. David Madigan, analyzed the Etminan Study and found it to be "methodologically sound" with a "highly statistically significant result."
Dr. Madigan discussed, at length, the strengths and limitations of case-control studies generally, as well as those of the Etminan Study specifically. See Madigan Rep., ECF No. 427-1 at 21-25, Madigan Supp., ECF No. 427-1 at 85-90; Madigan Tr., ECF No. 596-4 at 42-47, 54-58. In particular, with respect to the potential effect of bias on the Study's results, Dr. Madigan explained that the relative risk calculations are simply too "substantial" and "robust" to be explained by investigator bias. See Madigan Tr., ECF No. 596-4 at 70. In short, Dr. Madigan opines that a case-control study is "highly unlikely" to yield increased risk estimates like those found in the Etminan Study "in the absence of a true" association. See Madigan Supp., ECF No. 427-1 at 91. In his view, the FDA called for a case-control study "clarify[ing]" the association between Abilify and impulse control disorders, and the Etminan Study reliably did exactly that. See Madigan Tr., ECF No. 596-4 at 71.
Defendants argue that numerous methodological flaws render the Etminan Study unreliable under Rule 702 and Daubert , including a deficient study design, failure to account for the risk of confounders, and the presence of bias. They also challenge Dr. Madigan's defense of the Etminan Study, which they claim is untenable in light of his prior published research criticizing both healthcare database research and the use of p -values as a measure of statistical significance. The Court addresses each category of objections in turn.
a. Study Design
Defendants criticize the Etminan Study's use of the LifeLink database because the database was not designed for research purposes. This criticism has little, if any, merit. The use of health insurance claims databases for epidemiologic research is well-supported by the medical literature, which is an important consideration under Daubert.
With that said, large database research is not without limitations, one of which is the unavailability of medical records to confirm the accuracy of the data and to provide potentially significant clinical information not reported in the database. Defendants argue that this limitation is fatal to the Etminan Study's reliability under Daubert.
The LifeLink database, despite Defendants' criticisms, contains a sufficiently comprehensive dataset of patients, medical diagnoses and prescription claims to reliably serve the epidemiological objectives of the Etminan Study. Indeed, "claims data of this type provide some of the best data on drug exposure in pharmacoepidemiology." Brian L. Strom, Overview of Automated Databased in Pharmacoepidemiology , in PHARMACOEPIDEMIOLOGY 158, 159 (Brian L. Strom et al. eds., 5th ed. 2012), DX-129 at 2. The Etminan Study's statistical analysis of the LifeLink data is capable of being tested, and the Study itself has been subjected to peer review and publication in a reputable medical journal. This is all that Rule 702 and *1317Daubert require. See Chapman ,
Defendants' next argument, which relates to the database challenges addressed above, is that the Etminan Study is unreliable for its inability to confirm that individual patients in the LifeLink database were ever actually exposed to Abilify ; that is, that they actually took the Abilify they were prescribed. The Study did not attempt to validate medication usage, even though its lead author, Dr. Etminan, has done so in other epidemiological studies. This criticism also fails.
All epidemiological studies that make use of large healthcare databases are vulnerable to the risk of drug exposure misclassification, which is the risk of inaccurately measuring actual exposure to a drug. See Schneeweiss, 48 J. CLIN. EPIDEMIOLOGY at 328, DX-122 at 6. This is because claims databases only reflect the dispensing of medications and not actual medication use. See
The fact that the Etminan Study did not attempt to correct for the risk of drug exposure misclassification does not render it unreliable under Daubert. There is no evidence in the record of an established epidemiological protocol for addressing drug exposure misclassification concerns. See Kumho Tire, at 152,
Defendants' next argument with respect to the Etminan Study's design is that the Study cannot reliably measure the incidence of iatrogenic gambling (i.e. , medication-induced) in Abilify patients because it identified cases of gambling disorder in the LifeLink database using medical billing codes that are based on the DSM-5 diagnostic criteria for idiopathic gambling (i.e. , gambling disorder that occurs spontaneously and with no known cause).
Defendants' last argument is that the Etminan Study is unreliable because the time between exposure to Abilify and the diagnoses of pathological gambling in the random sample taken from the LifeLink database was too short to be compatible with a cause-effect relationship. This argument is based on the Study's finding that five patients were exposed to Abilify in the year preceding their diagnoses of pathological gambling, with an average, or mean, time to diagnosis of 20 days and a standard deviation of 17.4 days.
This criticism is not fatal to the Study's reliability under Daubert for several reasons. First, the standard deviation of 17.4 days does not dictate a conclusion that there must have been a three-day period between exposure and diagnosis for at least one of the five patients in the random sample analyzed in the Study. At his deposition, Dr. Etminan, the Study's lead author, testified that while the time-to-diagnosis for one of the patients could have been "a matter of days," he could "not [be] sure exactly what" the actual times-to-diagnosis were for any of the five patients "without having the data" from the LifeLink database to review.
Second, the possibility of pathological gambling or other impulse control symptoms developing within either three or eight days of exposure to Abilify is consistent with the scientific literature. Multiple published case reports describe a "rapid onset" of such symptoms following exposure to Abilify, with patients' times-to-onset ranging from a few days to a week after starting treatment with the drug.
Finally, as the Court has already found, the DSM-5 diagnostic criteria for gambling disorder do not govern the diagnosis of iatrogenic (medication-induced) gambling. See DSM-5, ECF No. 428-3 at 68. Indeed, the DSM-5 clearly contemplates that "patients taking dopaminergic medications" may "experience urges to gamble" that "dissipate when [the] medications are reduced in dosage or ceased." See
b. Confounders
Defendants also argue that the Etminan Study is unreliable for its failure to control for potential confounders, i.e. , known risk factors for pathological gambling, specifically, depressive disorders, anxiety disorder, and personality disorders. See DSJ, ECF No. 428-26 at 29. According to Defendants, this flaw is "independently fatal" to the Etminan Study because it means that the pathological gambling diagnoses in the LifeLink database could be attributable to one or more of these underlying conditions rather than Abilify, particularly since they are in many cases the precise medical conditions for which Abilify is prescribed. See DSJ Reply, ECF No. 484 at 10-11.
When assessing the reliability of an epidemiological study, a court must consider whether the study adequately accounted for confounding factors, or confounders. See Ref. Man. at 591; see also Deutsch v. Novartis Pharm. Corp. ,
Applying these principles to this case, the Court finds that the failure to control for depressive disorders, anxiety disorders, and personality disorders does not invalidate the results of the Etminan Study. First, Abilify is not indicated for treatment of anxiety or personality disorders. See Product Label, ECF No. 428-1 at 2, 4. Nothing in the record as it currently stands suggests that Abilify is even prescribed off-label for these two categories of psychiatric conditions. This is significant because, for epidemiological purposes, no matter how strongly a variable is related to the disease in question, if it is not also related in some way to drug exposure, it cannot be a true confounder. See Ref. Man. at 591; Weiss & Koepsell at 216. Here, there is no evidence that anxiety and personality disorders are related in any way to Abilify exposure.
Second, the medical literature is inconclusive on the question of whether depressive, anxiety and personality disorders are causal risk factors for pathological gambling. It is true that the DSM-5 provides that "[i]ndividuals with gambling disorder have high rates of comorbidity with" these categories of psychiatric conditions. Am. Psychiatric Ass'n, DIAGNOSTIC AND STATISTICAL MANUAL OF MENTAL DISORDERS 589 (5th ed. 2013) ("DSM-5"), ECF No. 428-3 at 68. It also is true that at least two cross-sectional studies have confirmed the prevalence of problem gambling behavior in the major depression and mood disorder populations.
*1324with major depressive disorder ), ECF No. 427-12. But "comorbidity" and "prevalence" are not synonymous with "causative." Notably, both cross-sectional studies explicitly caution against inferring a causal relationship from the presence of these observed comorbidities. See Quilty at 198, ECF No. 427-13 at 9; Kennedy at 574, ECF No. 427-12 at 8. The Quilty study, in particular, concluded that there is "no direct association" between pathological gambling and mood disorders, including depression. See Quilty at 198, ECF No. 427-13 at 9. In any event, "it is not possible to establish the temporal relation between exposure and disease-that is, that the exposure preceded the disease, which would be necessary for drawing any causal inference"-by reference to a cross-sectional study. Ref. Man. at 560-61. In sum, science has not yet determined with any reliability the precise nature of the relationship, if any, between pathological gambling and depressive, anxiety, and personality disorders. The Court may not simply ignore this gap in scientific understanding by excluding the Etminan Study for failing to consider these psychiatric conditions as causal risk factors for pathological gambling. See Hendrix II ,
Finally, other evidence in the record reliably supports the conclusion that depressive, anxiety, and personality disorders did not confound the results of the Etminan Study. For example, as part of a 2016 Pharmacovigilance Review, the FDA performed a disproportionality analysis of its adverse event reporting system database, comparing the relative frequency of pathological gambling reports among 11 different atypical antipsychotics, one of which was Abilify.
[* * * REDACTED * * *] .
In sum, confounding is a "reality" inherent in all epidemiological research. Ref. Man. at 590. As such, confounders "do not reflect an error made by" a particular researcher; rather "they reflect the inherently uncontrolled nature" of observational studies. See id. at 593 (internal marks omitted). Identifying and mitigating the effects of confounding is key to ensuring the reliability of an epidemiological study. See id. at 591-97; see also Deutsch v. Novartis Pharm. Corp. ,
c. Bias
Defendants further argue that the Etminan Study is unreliable because its results were compromised by bias. More specifically, they first argue that through his actions, Dr. Etminan created a conflict of interest that affects the integrity of the Study's findings. This argument is based on the fact that Dr. Etminan contacted Plaintiffs' counsel shortly after learning about this litigation on AboutLawsuits.com, before he developed the research protocol for the Study. The implication, of course, is that Dr. Etminan was predisposed towards results that would support Plaintiffs' theory of general causation in this case. The problem with Defendants' position is that the uncontroverted record evidence with respect to this communication does not demonstrate impropriety by either Dr. Etminan or Plaintiffs' counsel. According to Dr. Etminan, the conversation lasted only two minutes, during which he advised Plaintiffs' counsel that he intended to conduct a study on Abilify, gambling, and impulse control disorders, but he did not discuss any specifics about how the study would be designed or what its results might be. See Etminan Dep., ECF No. 457-7 at 27-30. Plaintiffs' counsel immediately ended the conversation and refrained from any further discussions about the study with Dr. Etminan until after it was published in a peer-reviewed journal.
Importantly, there is no evidence in the record to suggest that any methodological aspect of the Etminan Study or its results was tainted by Dr. Etminan's alleged bias. Although the Etminan Study has its limitations, see In re Orthopedic Bone Screw Prod. Liab. Litig. , No. 1014,
Defendants next argue that the Etminan Study is unreliable due to its failure to control for detection bias, also called reporting bias. In this context, detection bias refers to the possibility that pathological gambling and impulse control disorders were more likely to be detected and diagnosed in the exposed group (individuals taking Abilify ) than in the unexposed group, due to increased medical awareness of the particular problems allegedly associated with Abilify. See Zoloft I ,
The only evidence offered by Defendants to demonstrate the potential for detection bias in this case is a single "suspect adverse reaction report" by a patient who only reported having experienced an "urge to gamble" when he took Abilify after seeing an advertisement in 2014, which said that Abilify"causes compulsive gambling and was a bad drug." See ECF No. 460-13 at 1. A single adverse reaction report is insufficient to discredit the Etminan Study as a whole. As the Court has already noted, adverse event reports are "one of the least reliable sources" of scientific information. See *1327McClain ,
d. Dr. Madigan's Etminan Analysis
Defendants raise two objections to Dr. Madigan's statistical analysis of the Etminan Study.
From 2009 to 2013, Dr. Madigan served as principal investigator for the Observational Medical Outcome Partnership ("OMOP"), a public-private partnership between the FDA, academia, and the pharmaceutical industry that was established, in part, to empirically evaluate the strengths and weaknesses of observational healthcare database studies of the effects of medical products.
Dr. Madigan's published criticisms of generic automated database research do not contradict his endorsement of the Etminan Study because, in short, the Etminan Study is not the product of generic automated database research. Rather, it was custom-designed to analyze a very specific clinical question-whether Abilify is associated with pathological gambling and other impulse control disorders-and narrowly tailored to account for a number of factors unique to the LifeLink database and to the Abilify patient population. See Madigan Tr., ECF No. 596-4 at 44-45, 88-89; Madigan Dep., ECF No. 427-21 at 40. This customized design and implementation distinguishes the Etminan Study from the generic automated studies criticized by Dr. Madigan and the OMOP. Indeed, several of Dr. Madigan's publications actually recommend such "customizing [of] analyses to databases" and "thoughtful and careful study design" as means of improving the accuracy and performance of generic automated database research. See Madigan 2014, DX-117 at 27, 35; see also Madigan 2013b, ECF No. 427-8 ("It is conceivable that customizing the analytical approach to [drug-outcome] pairs could lead to greater consistency across databases."). The Etminan Study also implements many of the specific design-level and analytical strategies that Dr. Madigan and the OMOP suggest for reducing potential errors in generic automated database research, including careful matching of cases and controls, adjusting and controlling for potential confounders, and the use of sensitivity analyses to assess the potential consequences of unknown confounders. See Madigan 2014, DX-117 at 15-17. None of Defendants' experts disputed Dr. Madigan's explanation of the distinctions between customized database research, like the Etminan Study, and generic database research, like the studies criticized by Dr. Madigan. To the contrary, on this record, Dr. Madigan's opinion with respect to the Etminan Study is consistent with his prior *1329published literature and does not "violate[ ] his own standard of proper methodology." See Rezulin ,
Defendants also argue that Dr. Madigan's reliance on p -values to demonstrate the validity of the statistical evidence in this case is untenable in light of his published research criticizing traditional p -values for their vulnerability to systematic error, such as bias. See Martijn J. Schuemie et al., Interpreting Observational Studies: Why Empirical Calibration is Needed to Correct P-Values , 33 STATISTICS MED. 209 (2014) ("Schuemie 2014"), ECF No. 427-5 at 2, 3. The Court disagrees. The p -value is a generally accepted statistical technique for evaluating the significance of the results of a statistical analysis. See Ref. Man. at 249-56, 258; see also Jones v. City of Boston ,
While it is true that Dr. Madigan and his colleagues have proposed "a new empirical framework" for evaluating statistical significance, called a calibrated p -value, which they assert will "minimiz[e] the potential effects of bias when interpreting observational study results," see Schuemie 2014, ECF No. 427-5 at 3, this calibrated p -value framework is "controversial" and has not yet gained general acceptance or approval in the scientific community, Madigan Tr., ECF No. 596-4 at 50. Indeed, Dr. Madigan testified at his deposition that, at least as of that time, "the only people to have ever calculated calibrated p -values [were him]self and [his] coworkers." See Madigan Dep., ECF No. 427-1 at 148.
Based on the foregoing, the Court finds the Etminan Study is a scientifically sound epidemiological study and, therefore, reliable evidence of general causation in this case.
2. Dose-Response Relationship
In addition to epidemiology, Plaintiffs' experts offer a series of case studies and adverse event reports as evidence of a dose-response relationship between Abilify, impulsive gambling, and other impulse control disorders.
In the Eleventh Circuit, the use of dose-response evidence as a "primary" means of establishing causation generally requires a scientifically reliable showing of a correlation between dosage and disease, the minimum dose at which adverse effects are seen and the dose at which a substance is lethal. See McClain ,
In this case, Plaintiffs' experts have not presented any controlled, experimentally derived evidence of a dose-response relationship between Abilify and impulse control disorders. While the absence of such evidence is not fatal to the experts' general causation opinions, it does weaken the force and reliability of their conclusions as to dose-response. Nonetheless, the Court agrees with the FDA that a number of the published case studies-those describing positive dechallenge and rechallenge events, in particular-indicate a "temporal relationship between the initiation of [Abilify ] treatment and the onset of" impulse control problems. See FDA Pharm. Vigil., ECF No. 428-11 at 21-25. Some of these case studies and adverse event reports also strongly suggest that an increase in a patient's dose of Abilify may increase that patient's risk of impulse control problems, while a decrease in dose may correspondingly decrease the risk.
3. Background Risk
Two of Plaintiffs' experts, Drs. Glenmullen and Hollander, provide the background risk or prevalence of various *1332impulse control disorders, including compulsive gambling, in the general population, as reflected in the scientific literature. More specifically, Dr. Glenmullen, relying on the DSM-5, stated that the past-year prevalence rate of gambling disorder is approximately 0.2%-0.3% in the general population. See Glenmullen Rep., ECF No. 424-1 at 59.
The fact that Plaintiffs' experts do not offer a more expansive analysis of background risk in this case does not present a "serious methodological deficiency" or "substantial weakness" in their general causation opinions. See Chapman ,
4. Biological Plausibility
Plaintiffs' experts share the opinion that the biological mechanism by which Abilify can cause pathological gambling and impulse control disorders is its effect on dopamine neurotransmission in the brain.
According to Dr. Bechara, Abilify binds to over 90% of postsynaptic D2receptors in the nucleus accumbens and acts as a functional antagonist, occupying the D2receptors and preventing dopamine molecules from attaching and activating them, thereby blocking dopamine neurotransmission at those sites. The brain compensates for the resultant decrease in dopaminergic activity by increasing, or upregulating, the number of dopamine receptors in the nucleus accumbens; and also by increasing the sensitivity of those receptors, so that when activated by dopamine they produce greater, more "potentiated" physiological responses than would occur naturally. See Bechara Tr., ECF No. 596-3 at 100-101.
*1333At the same time, the "displaced" dopamine molecules, unable to bind to D2receptors, diffuse towards the other available receptors in the nucleus accumbens, most of which are D3receptors. Abilify occupies and "strongly stimulates" about 30% of these D3receptors, producing in them between 50% and 100% of the physiological response that dopamine naturally produces. See Bechara Rep., ECF No. 423-1 at 7. The remaining D3receptors, which are upregulating and hypersensitive, bind with the endogenous dopamine to produce "supercharge[d]" reward-seeking behavior. See Bechara Tr., ECF No. 596-3 at 98. Finally, Dr. Bechara also opines that Abilify's functional antagonism at D2receptors may disrupt the brain's ability to process the consequences of negative behavior.
Defendants challenge the reliability of Plaintiffs' experts' proposed mechanism of action on the ground that it lacks evidentiary support and instead is premised on "pure speculation." Def. Bechara Motion, ECF No. 423-10 at 17.
a. Displacement
Defendants argue that there is no scientific support for the proposition that endogenous dopamine is "displaced" when Abilify occupies a majority of D2receptors in the nucleus accumbens. See id. at 18. The Court disagrees. Even Defendants' own psychopharmacology expert, Dr. Pierre Blier, agrees that Abilify displaces dopamine at D2receptors. See Blier Dep., ECF No. 455-2 at 241, 248, 258-59.
Defendants also argue that there is no evidentiary support for a "key assumption" of the "displacement theory," namely, that Abilify"occup[ies] relatively more D2receptors than D3receptors." See id. , ECF No. 423-10 at 22 (citing Bechara Rep., ECF No. 423-1 at 13). Again, the Court disagrees. As explained in Maeda 2014, which is a peer-reviewed, published article relied on by Dr. Blier, see Blier Rep., ECF
*1334No. 455-1 at 15-16, the only available method for directly measuring human receptor occupancy is PET imaging, see Maeda 2014 at 600, DX-062 at 12. Where PET imaging is unavailable, in vitro studies of receptor affinity are used to predict receptor occupancy.
Dr. Bechara's opinion that "displaced" endogenous dopamine diffuses towards, and binds with, other available receptors in the nucleus accumbens, most of which are D3receptors, is also biologically plausible based on the scientific evidence in this case. It appears to be well-established in the scientific literature that, in humans, D3receptors predominate in the mesolimbic regions of the brain, including the nucleus accumbens.
Relatedly, the record evidence also reflects, and Defendants' experts have not disputed, that endogenous dopamine has "higher affinity for" D3receptors than D2receptors. See Tadori 2011a at 51, PX-021 at 9; see also Gurevich 1999 at 78 (stating that dopamine has "significantly higher affinity" for D3receptors than for D2receptors). Dr. Blier testified that displaced endogenous dopamine can diffuse "everywhere," see Blier Tr., ECF No. 596-8 at 27, including postsynaptic dopamine receptors "not located in precise apposition to" the presynaptic, sending neuron, see Blier Rep., ECF No. 455-1 at 15; see also Blier Dep., ECF No. 455-2 at 56-58. According to Dr. Blier, endogenous dopamine"diffuses all around the neuron" and may act on any of the "different types of receptors ... in that region." See Blier Tr., ECF No. 596-8 at 27. The scientific literature confirms Dr. Blier's opinion on this issue.
Taken together, this evidence reasonably and reliably supports the plausibility of Dr. Bechara's displacement opinion. In short, the scientific evidence reflects that (1) endogenous dopamine has a high affinity for D3receptors; (2) D3receptors are the predominant dopamine receptors in the mesolimbic pathway, including the nucleus accumbens; and (3) displaced endogenous dopamine may diffuse throughout that region of the brain. Under these conditions, it is certainly plausible that displaced endogenous dopamine would diffuse to, and activate, at least some of the D3receptors so abundant in the mesolimbic pathway.
At this point, the Court finds it important to emphasize that determining whether an expert's opinion is "biologically plausible" is a far different inquiry than determining whether an opinion is "biologically certain." See Daubert ,
b. Upregulation and Sensitization
Defendants also argue there is no medical support for Plaintiffs' experts' opinions that Abilify's functional antagonism of D2receptors triggers upregulation and sensitization of dopamine receptors in the brain. This is incorrect. Both phenomena have been described in published case reports
*1337Finally, the FDA also has acknowledged, based on the medical literature, that D3partial agonism, upregulation, and sensitization are plausible biological mechanisms that "could" explain the onset of impulse control disorders after Abilify exposure, although it cautioned that more research was necessary before any final conclusion can be reached. See FDA Pharm. Vigil., ECF No. 428-11 at 29. Given this evidence, Dr. Bechara's opinion as to upregulation and sensitization cannot be considered "improper ipse dixit. " See Def. Bechara Motion, ECF No. 423-10 at 26.
The fact that none of the other atypical antipsychotics is associated with a higher incidence of impulse control disorders, even though those drugs may "cause more upregulation than Abilify," see id. at 25, does not detract from the reliability of Dr. Bechara's opinion that Abilify can cause upregulation and sensitization. None of the scientific evidence in this case indicates that earlier atypical antipsychotics are agonists at D3receptors.
c. Direct Agonism
Defendants argue that Plaintiffs' experts do not have "any methodologically reliable basis" for concluding that Abilify acts differently at D3receptors than it does at D2receptors. See Def. Bechara Motion, ECF No. 423-10 at 12. More specifically, Defendants argue that (1) the in vitro studies offered in support of this conclusion may not reliably support an expert opinion on general causation; and (2) the only way Dr. Bechara can show any difference between Abilify's effects at D2and D3receptors is by "cherry-picking" data from the scientific landscape to give the illusion of clarity in favor of his biological plausibility opinion. Again, the Court disagrees.
Before addressing the merits of Defendants' objection, it is necessary to clarify what is not in dispute. Defendants do not dispute the apparent scientific consensus that Abilify is considered a partial agonist that acts as a functional antagonist at postsynaptic D2receptors.
First, there is support in the scientific literature for the fact that "the actions of [Abilify ] differ markedly across [dopamine ] receptor systems." David A. Shapiro et al., Aripiprazole, A Novel Atypical Antipsychotic Drug with a Unique and Robust Pharmacology , 28 NEUROPSYCHOPHARMACOLOGY 1400, 1407-08 (2003) ("Shapiro 2003"), DX-45 at 8-9. For example, one in vitro study using animal cells transfected with human dopamine receptors found that, at least in a controlled laboratory environment, Abilify was "sometimes an antagonist (e.g. , D2), sometimes a partial agonist (e.g. , D2), and sometimes a full agonist (D3, D4)." See id. at 1408, DX-45 at 9. This finding is consistent with subsequent scientific literature, which has characterized Abilify as "functionally selective" for its "markedly different" effects at individual D2and D2-like receptors in the various dopamine pathways. See Richard B. Mailman and Vishakantha Murthy, Third Generation Antipsychotic Drugs: Partial Agonist or Receptor Functional Selectivity , 16 CURRENT PHARM. DESIGN 488, 492-93 (2011), DX-069 at 5-6. This evidence reliably supports a fundamental premise of Plaintiffs' experts' proposed mechanism of action, that Abilifycan act differently at postsynaptic D3receptors than it acts at postsynaptic D2receptors.
Second, there is scientific literature reflecting that Abilify is not an antagonist at D3receptors. Yoshiro Tadori et al., Characterization of Aripiprazole Partial Agonist Activity at Human Dopamine D3 Receptors , 597 EUROPEAN J. PHARMACOLOGY 27, 31 (2008) (in vitro study) ("Tadori 2008"), DX-58 at 5. This fact alone supports a distinction between Abilify's effects at postsynaptic D2receptors (functional antagonism) and its effects at D3receptors (no antagonism).
Finally, multiple in vitro studies show that Abilify exhibits strong partial to full agonist activity at D3receptors,
The fact that Plaintiffs' experts rely primarily on in vitro data does not invalidate their conclusions as to this proposed mechanism of action. In vitro studies are often "the only or best available evidence" of a drug's effects at the cellular level. See Ref. Man. at 564. However, because of its limitations (e.g. , ethical concerns, problems extrapolating from laboratory experimental findings to humans), in vitro evidence cannot be the sole basis for a general causation opinion. See Kilpatrick ,
In this case, Dr. Bechara acknowledged the limitations of in vitro research and explained which of the in vitro findings about Abilify reliably "reflect what happens in a normal human brain." See Bechara Tr., ECF No. 596-3 at 91. This is all that Rule 702 and Daubert require. Moreover, Defendants have not contradicted Dr. Bechara's explanation, nor have they argued that any specific in vitro study he presented is methodologically flawed. Finally, Defendants [* * * REDACTED * * *] .
Defendants argue that Dr. Bechara "cherry picked" two data points that support his biological plausibility opinion and "ignore[d] the numerous studies that are inconsistent with" it. Def. Bechara Motion, ECF No. 423-10 at 18-19. The first data point was reported in Shapiro 2003, which stated that Abilify exhibited both partial and full agonist actions at D3receptors. See Shapiro 2003, DX-045 at 2, 9. The second data point was drawn from Hamamura 2008, which calculated Abilify's intrinsic activity at D2receptors to be approximately 6%. See Hamamura 2008 at 864, DX-057 at 3. Defendants claim Dr. Bechara deliberately presented only these two data points to the Court, and no others, *1340in order to accentuate the alleged disparity between Abilify's effects at D2and D3receptors. The Court is not persuaded. The uncontroverted evidence-including Dr. Bechara's expert reports and his testimony at the Daubert hearing-shows that Dr. Bechara performed an extensive and systematic review of the scientific literature on Abilify's intrinsic activity at D2and D3receptors. See, e.g. , Bechara Rep., ECF No. 423-1 at 21-25; Bechara Supp., ECF No. 423-1 at 448-454; Bechara Tr., ECF No. 596-3 at 82-83.
Finally, Defendants' argument that Dr. Bechara "ignore[d] the numerous studies that are inconsistent with his opinion," see Def. Bechara Motion, ECF No. 423-10 at 18-19, fails because it misrepresents the findings of the "numerous" in vitro studies that Defendants claim Dr. Bechara ignored. While it is true that there are studies in the medical literature evidencing Abilify's partial agonism at D2receptors, at least six of those studies report findings related to Abilify's effects at presynaptic D2receptors.
Moreover, according to Dr. Bechara, five studies, including all but one of the studies discussed above involving presynaptic D2receptors, also report in vitro findings based on tissue cultures that were "artificially manipulated" by researchers to increase the number of D2receptors, called a *1341receptor reserve, far beyond the amount present in the human brain.
There are two other scientific articles containing data points that Defendants claim Dr. Bechara ignored. The first, Lawler 1999, DX-051, Dr. Bechara clearly cites in his expert report, see Bechara Rep., ECF No. 423-1 at 12. Moreover, at the Daubert hearing, Dr. Bechara referenced the Lawler article as part of the basis for his opinion that Abilify exerts very low partial agonist to antagonistic action at postsynaptic D2receptors. See Bechara Tr., ECF No. 596-3 at 92. The second article, Maeda 2014, DX-062, described an in vitro finding that Abilify exhibited 61% intrinsic activity at postsynaptic D2receptors. At the Daubert hearing, Dr. Bechara acknowledged that he did not rely on or cite the Maeda article as part of his opinion in this case. See Bechara Tr., ECF No. 596-3 at 126. However, there is no evidence that Dr. Bechara knew of and willfully excluded the Maeda article from his analysis. There also is no evidence that his search of the scientific literature was in any other way infirm. Under these circumstances, the Court finds that Dr. Bechara's failure to cite a single article out of the vast body of scientific literature connected with this case cannot render his entire analysis and opinion unreliable. This issue may be fodder for vigorous cross-examination, but it is not grounds for exclusion of Dr. Bechara's testimony.
In sum, the Court finds there is a methodologically sound basis for Dr. Bechara's conclusion that Abilify acts with greater intrinsic activity at D3receptors than it does at postsynaptic D2receptors. Dr. Bechara did not simply ignore the medical science that did not support his opinion. Instead, he analyzed all of the available medical literature and explained how and why certain studies did not alter *1342or undermine his opinion regarding Abilify's functional antagonism at postsynaptic D2receptors and partial agonism at D3receptors. Defendants' criticisms go to the credibility, and thus the weight, of Dr. Bechara's opinion, not its admissibility.
d. Negative Reward Prediction Error
Defendants also argue there is insufficient evidentiary support for Dr. Bechara's opinion that Abilify impairs negative reward prediction error, also called reversal learning. On this issue, the Court agrees. Reward prediction error learning refers to the process by which the brain learns from associations between actions and consequences. The mesolimbic dopamine system plays a central role in such reward-motivated behavior. See Roy A. Wise, Brain Reward Circuitry: Insights from Unsensed Incentives , 36 NEURON 229, 234 (2002) ("Wise 2002").
Dr. Bechara opines that Abilify may cause pathological gambling and impulse control disorders by preventing the dopamine "dip" that is critical for "teach[ing]" an individual to avoid activities with negative consequences. See Bechara Rep., ECF No. 423-1 at 11. According to Dr. Bechara, Abilify's functional antagonism at 90% of D2receptors signals a drop in baseline dopamine concentration, which triggers increased tonic transmission of dopamine. The excess tonically fired dopamine accumulates in the synapses and offsets, or blocks the effects of, the phasic dopamine dips associated with negative prediction errors. Without the phasic dips, no negative dopaminergic signal is sent when an activity should be stopped and avoided. The behavioral effect is an increase in risky, reward-directed activities, such as pathological gambling and other impulse control disorders, despite the potential for and occurrence of negative consequences.
As support for his negative reward prediction error opinion, Dr. Bechara relies heavily on the findings of a 2006 study investigating reward and punishment processing in Parkinson's disease patients taking one or more dopamine replacement medications, none of which was Abilify.
*1343See Roshan Cools et al., Reversal Learning in Parkinson's Disease Depends on Medication Status and Outcome Valence , 44 NEUROPSYCHOLOGIA 1663 (2006) ("Cools Study"), DX-143. The Cools Study found that patients on dopamine replacement medications exhibited "significantly impaired" capacity to process and learn from unexpected negative outcomes (i.e. , punishment) relative to healthy controls. See id. at 1670, DX-143 at 8. Consistent with theoretical models proposed in earlier medical literature, the Cools Study attributed the patients' negative reward prediction errors to artificially high tonic dopamine levels induced by the dopamine replacement medications, which the authors hypothesized as having functionally eliminated the effectiveness of phasic dopamine dips. See id. at 1669, DX-143 at 7.
The Court finds that the Cools Study cannot reliably establish biological plausibility in this case because it involved dopamine replacement medications that either directly increase dopamine levels in the brain (e.g. , Levodopa ) or directly stimulate dopamine receptors, including D2receptors, by mimicking the activity of endogenous dopamine (e.g. , full agonists like Mirapex). None of the drugs in the Cools Study were functional antagonists at D2receptors like Abilify, blocking dopamine neurotransmission at those sites. Importantly, none of Plaintiffs' experts explained why the Cools Study's findings as to the behavioral effects of stimulating D2receptors through dopamine replacement therapy can be extrapolated to reliably predict the behavioral effects of a D2receptor antagonist. See McClain ,
Additionally, a 2015 study of reversal learning in individuals taking the D2receptor antagonist Sulpiride, which was cited by Dr. Hollander, also presents an extrapolation problem, although it is a closer call. See L. Janssen et al., Abnormal Modulation of Reward Versus Punishment Learning by a Dopamine D2-Receptor Antagonist in Pathological Gamblers , 232 PSYCHOPHARMACOLOGY 3345 (2015) ("Janssen Study"), DX-189. The Janssen Study found that administration of the drug Sulpiride impaired reversal learning in healthy controls, but did not appear to alter reversal learning in pathological gamblers. The Study's authors also described the "seemingly paradoxical" state of the scientific literature with respect to a relationship between D2receptor antagonism and reward prediction error learning: some studies report that D2receptor antagonists impaired reward prediction error learning, while other studies report that they improved it. See id. at 3350-51, DX-189 at 6-7. None of the studies investigating D2receptor antagonism and reward prediction errors involved Abilify. Moreover, none of Plaintiffs' experts even attempted to explain how or why Abilify is sufficiently similar to Sulpiride in its mechanism of *1344action to warrant an extrapolation. This is significant because within a given class of drugs-such as D2receptor antagonists-there may be "great chemical diversity" and those "minor deviations in chemical structure can radically change a particular substance's properties and propensities." See Rider ,
e. Conclusion
In sum, the Court finds Plaintiffs' experts' biological plausibility opinions that Abilify can cause impulse control problems through its effects on dopamine neurotransmission in the brain to be scientifically reliable, based on current biochemistry and pharmacological knowledge. Each element of this proposed mechanism of action is adequately supported by peer-reviewed, published scientific literature and sound scientific reasoning. Moreover, Plaintiffs' experts' opinions are consistent with the FDA's assessment, based on the scientific literature, that Abilify's partial agonism, upregulation, and sensitization "could theoretically stimulate dopamine transmission in the mesolimbic pathway, a core component of the brain reward circuitry, providing biological plausibility for treatment-emergent [impulse control disorders ]." See FDA Pharm. Vigil., ECF No. 428-11 at 4, 29. The opinions are also consistent with [* * * REDACTED * * *] . Finally, Plaintiffs' experts' proposed mechanism of action is consistent with [* * * REDACTED * * *] .
5. Case Studies and Adverse Event Reports
Since 2010, there have been hundreds of reports of gambling and/or impulse control disorders in patients treated with Abilify. A number of the reports are published case studies that contain details about dosage, duration of use, concomitant medications, comorbid conditions, and other pertinent clinical information.
Although it is true that case studies and other anecdotal evidence may not, standing alone, support a general causation opinion, Rider ,
6. Disproportionality Analyses
Several statistical analyses, called disproportionality analyses, have been conducted by the FDA and Defendant Otsuka on the FAERS and VigiBase adverse event reporting databases, comparing the relative frequency of pathological gambling reports among various patient populations.
As the Court already discussed, the FDA's disproportionality analysis of the FAERS database found a statistically significant, disproportionately higher proportion of patients reporting pathological gambling with Abilify relative to all other atypical antipsychotics. See FDA Pharm. Vigil., ECF No. 428-11 at 28. The FDA calculated an EB05 score of 6.304 for this finding, which represents a statistically significant result. Defendant Otsuka [* * * REDACTED * * *] .
Defendants argue, again broadly, that disproportionality analyses cannot establish causation. The Court agrees. The safety signals identified through disproportionality analyses in this case "do not, by themselves, demonstrate [a] causal association." See FDA Pharm. Vigil., ECF No. 428-11 at 28. However, they do reliably support a conclusion that pathological gambling is disproportionately reported with Abilify relative to all other antipsychotics. See
D. Expert-Specific Challenges
1. Plaintiffs' Experts
a. Antoine Bechara, Ph.D.
Dr. Antoine Bechara is a professor of neuroscience and psychology at the University of Southern California with extensive professional experience in neurobiology and, in particular, the anatomical and neurotransmitter systems involved in human decision-making, behavioral addictions, and gambling. ECF No. 423-1 at 2. He is offered primarily for the purpose of explaining how Abilify can cause Plaintiffs' impulse control disorders. More specifically, Dr. Bechara has offered his opinion that there is a biologically plausible mechanism by which Abilify causes impulsive gambling and other impulse control behaviors, *1347namely, its effect on dopamine neurotransmission in the brain. Defendants challenge Dr. Bechara's testimony on qualification and reliability grounds. The Court has already found that the science on which Dr. Bechara based his biological plausibility opinion is reliable. See supra Section II(C). Therefore, the only question that remains to be resolved with respect to Dr. Bechara is whether he is qualified to render an expert opinion in this case.
Defendants argue that Dr. Bechara is not qualified to offer opinions on biological plausibility or general causation because he does not have a medical degree or a degree in pharmacology, has never diagnosed or treated patients with impulse control disorders, and has conducted no independent studies into how Abilify affects brain chemistry. As to biological plausibility, the Court disagrees. First, the record evidence reflects that Dr. Bechara does, in fact, have "a university degree in pharmacology from the University of Toronto," as well as a Ph.D. in neuroscience. ECF No. 423-1 at 80-82. More importantly, Dr. Bechara has over 25 years of clinical experience studying, publishing, and teaching courses on brain function and the effects of drugs-both prescription and street drugs-on human behavior. Of particular relevance to this case is the extensive research Dr. Bechara has conducted on dopamine systems and the neurobiological mechanisms of human decision-making, substance use and abuse, and behavioral and psychiatric disorders, including impulsive gambling and other impulse control disorders. He has written and collaborated on hundreds of peer-reviewed articles, papers, and book chapters on these subjects. Finally, Dr. Bechara developed the Iowa Gambling Task, which is currently used worldwide to detect and measure brain dysfunction and decision-making deficits in numerous clinical populations. As Dr. Bechara has not been offered as a medical doctor, it is irrelevant that he lacks a medical degree. Given the breadth of Dr. Bechara's knowledge and clinical experience in the field of neurobiology, the fact that he had not studied Abilify until he became involved in this case does not disqualify him from reviewing the scientific literature and offering an expert opinion on Abilify's mechanism of action.
As to a more comprehensive general causation opinion-that is, an opinion beyond the neurobiological mechanisms by which Abilify can cause pathological gambling or impulse control disorders-the Court agrees with Defendants. Although Dr. Bechara's expert reports frequently frame his conclusions in very broad and definitive language (i.e. , explaining that Abilify"causes" impulsive behaviors, rather than how it "can cause" the behaviors), most of the scientific support for his positions relates only to biological plausibility. His opinion does not meaningfully depend on any of the three categories of primary evidence considered indispensable in the Eleventh Circuit. He did not perform a Bradford Hill or weight-of-the-evidence analysis of general causation.
*1348No. 423, is granted with respect to medical causation and denied with respect to biological plausibility.
b. Joseph Glenmullen, M.D.
Joseph Glenmullen, M.D. is a board-certified psychiatrist and lecturer in psychiatry at Harvard Medical School, with more than 30 years of clinical experience treating psychiatric patients in private practice. Dr. Glenmullen offers a general causation opinion that Abilify is capable of causing pathological gambling and impulse control disorders. Dr. Glenmullen supports his opinion with epidemiological evidence (i.e. , the Etminan Study), medical literature evidencing a plausible mechanism of action, case and adverse event reports, disproportionality analyses and clinical trial data, all of which he analyzed under the Bradford Hill factors.
i. Qualification
Defendants argue that Dr. Glenmullen lacks the requisite expertise to offer opinions related to general causation, such as biological plausibility, epidemiology, toxicology, biostatistics, FDA regulations, and pathological gambling. In essence, Defendants contend that Dr. Glenmullen's medical education, post-graduate training, and professional experience in the field of psychiatry do not translate into qualifications that enable him to testify competently based on the scientific evidence in this case. Defendants read the "qualification" prong of Rule 702 too stringently. "An expert is not necessarily unqualified simply because [his] experience does not precisely match the matter at hand." Furmanite Am., Inc. v. T.D. Williamson, Inc. ,
In this case, the Court finds Dr. Glenmullen at least minimally qualified to offer expert opinions that will assist the trier of fact in understanding and resolving general causation issues related to biological plausibility, epidemiology, toxicology, and pathological gambling. Again, Dr. Glenmullen is a medical doctor and board-certified psychiatrist who has spent most of his career training psychiatric residents at Harvard Medical School and treating psychiatric patients in private practice, including "plenty of" patients with pathological gambling or impulse control disorders, albeit none with a diagnosis of drug-induced pathological gambling.
The fact that Dr. Glenmullen is not an epidemiologist does not disqualify him from testifying about epidemiological studies. See United States v. Thorn ,
ii. Reliability and Helpfulness
Defendants challenge the reliability of Dr. Glenmullen's methodology on two primary grounds. First, they argue that the evidence on which Dr. Glenmullen bases his opinion is unreliable and, thus, insufficient to support his opinion. Second, Defendants maintain that Dr. Glenmullen did not reliably apply the Bradford Hill factors in reaching his conclusion on general causation. With one exception, the Court disagrees.
With respect to the evidence, the Court has already found that most of the scientific literature on which Dr. Glenmullen relied, including the Etminan Study, is sufficiently reliable to support or bolster his general causation opinion. See supra Section II(C). However, one of the studies cited by Dr. Glenmullen, referred to by the parties as the Moore Study, must be excluded as unhelpful in this case. See Thomas J. Moore et al., Reports of Pathological Gambling, Hypersexuality, and Compulsive Shopping Associated with Dopamine Receptor Agonist Drugs , 174 JAMA INTERNAL MED. 1930, 1930-33 (2014) ("Moore Study"), ECF No. 428-10 at 2-5. The Moore Study is based on a disproportionality analysis of the FAERS database examining the association between six dopamine receptor agonist drugs and "unusual but severe" impulsive behaviors.
The Court has no reason to doubt the reliability of the Moore Study's methodology or findings as to those six drugs. But as to Abilify, "there is simply too great an analytical gap" between the Moore Study and any conclusion about a possible association between Abilify and reports of severe impulsive behaviors. See Joiner ,
Defendants final argument for excluding Dr. Glenmullen is that he did not reliably apply the Bradford Hill factors in reaching his general causation opinion. More specifically, Defendants contend that Dr. Glenmullen erred by applying the Bradford Hill factors at all because there is no reliable epidemiological study in existence finding a statistically significant association between Abilify and impulsive behaviors. Since the Court has already found that the Etminan Study reliably establishes the requisite association, this challenge is moot.
Defendants also argue that even if Dr. Glenmullen had statistically significant epidemiological evidence of an association between Abilify and compulsive behaviors, he misapplied the Bradford Hill factors by "giv[ing] all of the criteria equal weight" and "discussing each criteria in check-the-box fashion." See Def. Glenmullen Motion, ECF No. 424-15 at 37.
Dr. Glenmullen began his Bradford Hill analysis by assessing the "experiment" and "strength of association" factors, which address whether a body of experimental findings exists showing a statistically significant association between a drug and disease of interest. See Ref. Man. at 602. Dr. Glenmullen identified several experimental studies showing a statistically significant association between either (1) Abilify and diagnoses of gambling and other impulse control disorders
Regarding temporality and cessation of exposure, Defendants concede that the numerous case studies cited by Dr. Glenmullen "show ... a temporal relationship" between the use of Abilify and "a change in the presence or severity of symptoms" of gambling and other impulse control disorders. See Def. Glenmullen Motion, ECF No. 424-15 at 24. These case studies, as well as the many adverse event reports Dr. Glenmullen describes, are strongly suggestive of a dose-response relationship between Abilify, gambling and other impulse control disorders. Dr. Glenmullen also references [* * * REDACTED * * *] .
*1353See Glenmullen Rep., ECF No. 424-1 at 134. Defendants do not question Dr. Glenmullen's characterization of the clinical trial data.
Dr. Glenmullen also considered alternative explanations for the association between Abilify, impulsive gambling, and other impulse control disorders by reference to the Etminan Study, FDA's disproportionality analysis, Bristol-Myers Squibb disproportionality analyses and clinical trial data, and other medical literature. See
As to biological plausibility, Dr. Glenmullen concluded from the medical literature, as did Plaintiffs' other experts, that the biological mechanism by which Abilify can cause impulsive behaviors is its effect on dopamine neurotransmission in the brain. See
On balance, the Court finds that Dr. Glenmullen's application of the Bradford Hill factors is sufficiently reliable to support a conclusion that the observed association between Abilify and impulsive behaviors, such as pathological gambling, reflects a "true cause-effect relationship." See Ref. Man. at 597. Accordingly, Defendants' Motion to Exclude the General Causation Opinion of Joseph Glenmullen, ECF No. 424-15, is due to be denied.
c. Eric Hollander, M.D.
Dr. Eric Hollander is a board-certified psychiatrist and clinical professor at Albert Einstein College of Medicine, with specialized training and experience in the fields of psychopharmacology and neuropsychopharmacology,
i. Qualification
Defendants argue that Dr. Hollander is not qualified to offer a general causation opinion because he lacks sufficient training and experience in the fields of epidemiology and toxicology. The Court disagrees. As already explained, a witness may be qualified "by knowledge, skill, experience, training, or education" to offer an expert opinion that will help the trier of fact understand the evidence or resolve a factual issue. See Fed. R. Evid. 702. The qualification standard is "not stringent" and "so long as the witness is minimally qualified, objections to the level of [his] expertise go to credibility and weight, not admissibility." Hendrix I ,
In this case, the Court finds that Dr. Hollander is amply qualified to offer an expert opinion on whether Abilify can cause impulse control disorders. Dr. Hollander is a medical doctor and board-certified psychiatrist with over thirty years of experience researching, publishing, and teaching in the fields of psychopharmacology and neuropsychopharmacology. See Hollander Curriculum Vitae, ECF No. 459-1 at 38-96. This background, with its emphasis on the study of how psychiatric drugs affect brain chemistry and behavior, well equips Dr. Hollander to assist the trier of fact in understanding the biological mechanisms by which Abilify can cause impulsive behaviors. Dr. Hollander also has formal training in epidemiology, has "worked closely with epidemiologists to publish epidemiologic papers in peer review[ed] journals," and as an academic, has taught "epidemiologic principles as it relates to psychiatry and psychopharmacology" to "medical students, residents, and fellows." See Hollander Tr., 596-4 at 114-15. This specialized education and experience with epidemiology qualifies Dr. Hollander to give an expert opinion about the epidemiological study in this case (i.e. , the Etminan Study). See Thorn ,
Notably, Defendants do not dispute that Dr. Hollander is a leading expert on the etiology and treatment of impulse control disorders, including impulsive gambling. Indeed, Dr. Hollander was a member of the research agenda workgroup that, quite literally, wrote the DSM-IV diagnostic criteria for pathological gambling and, several years later, he oversaw the reorganization of the DSM-5 diagnostic criteria for gambling disorder and impulse control disorders.
ii. Reliability
Defendants challenge the reliability of Dr. Hollander's general causation opinion on two primary grounds. First, they argue that the evidence on which Dr. Hollander bases his opinion is unreliable and, thus, insufficient to support his opinion. Second, Defendants maintain that Dr. Hollander did not reliably analyze the evidence in reaching his conclusion on general causation.
Regarding the evidence, the Court has already found that most of the scientific literature on which Dr. Hollander relied, including the Etminan Study, is sufficiently reliable to support or bolster his general causation opinion. See supra Section II(C). Only one of Defendants' specific evidentiary challenges warrants additional comment. As part of the support for his general causation opinion, Dr. Hollander cites a 2016 article from the scientific literature comparing the characteristics of "possibly iatrogenic" problem gambling in patients taking Abilify with the characteristics of such gambling in patients taking a full dopamine replacement therapy.
The problem with Defendants' challenge to the Grall-Bronnec Article is that neither Dr. Hollander nor the Article's authors offered the Article as epidemiological evidence of causation. See Hollander Rep., ECF No. 459-1 at 22; Grall-Bronnec Article, ECF No. 425-4 at 7. Defendants' argument appears to be based on a misinterpretation of the authors' use of the term "cohort" to describe the "problem gamblers" who were interviewed as part of their research. A "cohort," as defined by Merriam-Webster, is "a group of individuals having a statistical factor (such as age or class membership) in common in a demographic study." See Merriam-Webster *1356Online Dictionary, https://www.merriam-webster.com/dictionary/cohort (retrieved Dec. 3, 2017). In this case, the Grall-Bronnec Article's authors evaluated a group of individuals with the statistical factors of problem gambling and Abilify use in common. Thus, the term "cohort" aptly describes the subjects of their work. A "cohort," as used in this context, differs from a "cohort study," which is a type of epidemiological study used to "measure and compare the incidence of disease" in certain populations. See Ref. Man. at 557. Neither Dr. Hollander nor the Article's authors characterize the Grall-Bronnec Article as a cohort study, and neither treats the Article's findings as carrying the same weight as epidemiology. Indeed, the Grall-Bronnec Article's authors actually recommend a cohort study as "a promising way to obtain further evidence" on causation. See Grall-Bronnec Article, ECF No. 425-4 at 7.
While the Court agrees that the Grall-Bronnec Article is not based on epidemiology, that fact does not preclude Dr. Hollander from relying on the Article as support for his general causation opinion. The Grall-Bronnec Article's authors' objective was to further scientific understanding of the nature of iatrogenic gambling by analyzing the sociodemographic profiles, gambling characteristics, comorbidities, and personality traits of patients whose "problem gambling" behaviors "could possibly result from an adverse drug reaction after the administration of a dopamine medication." See id. , ECF No. 425-4 at 3-4. The authors identified nine published case reports and conducted in-person clinical evaluations of eight individual patients in treatment for problem gambling, resulting in 17 discrete cases involving the use of Abilify.
The Court finds that the Grall-Bronnec Article presents a reliable and probative analysis of 17 patients' personal experiences while taking Abilify. In particular, the authors' in-depth clinical assessments and comparisons of the eight individual patients facilitate understanding and evaluation of the characteristics associated with "possibly" iatrogenic (medication-induced) gambling.
Defendants' last argument for excluding Dr. Hollander is that he did not reliably analyze the scientific evidence in this case. More specifically, Defendants contend that Dr. Hollander improperly relied on the Naranjo Scale and WHO-UMC criteria, which are specific causation methodologies, to reach his general causation opinion.
With respect to the Naranjo Scale and WHO-UMC criteria, Defendants' argument is misplaced because Dr. Hollander did not employ either technique during his analysis of the scientific evidence in this case. Dr. Hollander testified that he used a weight-of-the-evidence methodology and fully considered all of the Bradford Hill factors. See Hollander Tr., ECF No. 596-4 at 117-19. This is evident from Dr. Hollander's initial expert report, which, in addition to explicitly citing his reliance on the Bradford Hill factors, demonstrates that he applied those factors, in substance, in reaching his general causation opinion. See Hollander Rep., ECF No. 459-1. Dr. Hollander only ever mentions the Naranjo Scale or WHO-UMC criteria twice-once to identify them as "additional method[s]" for determining whether a drug caused an isolated adverse medical event, see id. at 12, and once to disclose that the authors of the Grall-Bronnec Article used the Naranjo Scale to assess whether Abilify caused the "problem gambling" behaviors exhibited by individual patients in their cohort, see id. at 22.
Defendants' challenge to the reliability of Dr. Hollander's application of the Bradford Hill factors also fails. As an initial matter, Defendants' argument that Dr. Hollander erred by considering the Bradford Hill factors at all is moot because the prerequisite for applying those factors-that is, an epidemiological study reliably establishing a statistically significant association between the use of a drug and an adverse medical effect-is satisfied by the Etminan Study. See Section II(C). Thus, the only remaining question is whether Dr. Hollander reliably weighed the Bradford *1358Hill factors as part of his general causation analysis.
Dr. Hollander found a "very strong" association between Abilify and impulse control disorders based on his assessments of the Etminan Study, the FDA's 2016 Pharmacovigilance Review and [* * * REDACTED * * *] . See Hollander Tr., 596-5 at 37. As the Court has already observed, this evidence reliably establishes the existence of a statistically significant association between both (1) Abilify and medical diagnoses of pathological gambling and other impulse control disorders ; and (2) Abilify and adverse event reports of pathological gambling and other impulse control disorders. The Bradford Hill factor of specificity is also met, as the association in this case involves only the very narrow and specific adverse effect of impulse control problems. Dr. Hollander found that the evidence also reliably demonstrates the Bradford Hill factor of consistency, in that the association has been shown to be consistently present in a number of different analyses using different criteria, populations and methods. See Hollander Rep., 459-1 at 27; Hollander Tr., ECF No. 596-5 at 36. As Dr. Hollander noted, there does not appear to be "any evidence at all that suggests" there is no association between Abilify and impulsive behaviors. See Hollander Tr., ECF No. 596-5 at 38.
As to temporality, Dr. Hollander cites numerous case studies and adverse event reports in which impulsive behaviors emerged only after a patient's exposure to Abilify. See Hollander Rep., ECF No. 459-1 at 23. These case studies and adverse event reports, although not dispositive of the issue, also are strongly suggestive of a dose-response relationship between Abilify and impulse control disorders. See Section II(C); Hollander Rep., ECF No. 459-1 at 30-31. Moreover, the reports of dechallenge events, in particular, satisfy the Bradford Hill factor of cessation of exposure, as they reliably demonstrate that, with many individual patients, impulse control problems disappeared once Abilify was decreased or discontinued.
Much like Dr. Glenmullen, Dr. Hollander ruled out alternative explanations for the association between Abilify and impulsive behaviors by reference to the Etminan Study and the FDA's 2016 Pharmacovigilance Review, as well as to case studies describing dechallenge events. According to Dr. Hollander, the FDA's disproportionality analysis of 11 different atypical antipsychotics is particularly significant because, although those medications all treat the same patient population with the same underlying conditions, only Abilify showed a statistically significant incidence of adverse event reports involving uncontrollable impulsive behaviors. See Hollander Tr., ECF No. 596-1 at 25-27. Dr. Hollander concluded that if the patients' underlying psychiatric conditions caused the uncontrollable impulses, then all of the atypical antipsychotics should have had statistically significant reporting of impulse control problems. See id. Dr. Hollander observed that the Etminan Study specifically controlled for bipolar disorder, schizophrenia, and substance abuse disorder, which ruled out those conditions as possible explanations for the association between Abilify and impulsive behaviors. See Hollander *1359Rep., ECF No. 459-1 at 33; Hollander Tr., 596-5 at 71.
Regarding the Bradford Hill factor of biological plausibility, Dr. Hollander's opinion as to Abilify's mechanism of action "mirror[s]" that of Plaintiffs' neurobiology expert, Dr. Antoine Bechara, see Def. Hollander Motion, ECF No. 425-14 at 24, and is reliable for the same reasons, see Section II(C). This proposed biological mechanism of action-Abilify's effect on dopamine neurotransmission in the brain-is coherent with existing scientific knowledge about psychopharmacology, neuropsychopharmacology, and the biochemistry of the brain. See Section II(C). Importantly, Dr. Hollander demonstrated a comprehensive understanding of the scientific evidence in support of his opinion. In sum, the Court finds that Dr. Hollander reliably considered all of the Bradford Hill factors in reaching his opinion that Abilify can cause impulse control problems. Dr. Hollander also reliably explained his methodology, reasoning and conclusions at length, both in his expert reports and at the Daubert hearing. See Hollander Rep., ECF No. 459-1 at 1-36; Hollander Supp., DX-641;
d. Russell V. Luepker, M.D.
Dr. Russell V. Luepker is a board-certified cardiologist, and a professor of public health and medicine at the University of Minnesota. He holds a master's degree in epidemiology from Harvard University, is certified in epidemiology by the American College of Epidemiology, and served as head of the Division of Epidemiology at the University of Minnesota for over 13 years. Dr. Luepker also has over 40 years of experience researching, publishing, and teaching on the "design, implementation and interpretation of clinical research" methods. See Luepker Rep., ECF No. 462-1 at 3.
The "primary focus" of Dr. Luepker's "teaching, research, and clinical career" has been epidemiology and other types of clinical research in humans. See Luepker Rep., ECF No. 462-1 at 2. The Court is of the view that this background well equips him to offer unique insights into the methodological soundness of the only epidemiological evidence in this case, the Etminan Study. Yet, Dr. Luepker devotes just a single paragraph of his initial expert report to the Etminan Study, in which he provides only a cursory statement of the Study's findings and nothing more. See id. at 10. Almost two pages of his rebuttal report discuss the Etminan Study further, but this too lacks any meaningful analysis *1360beyond general assertions about health insurance claims database research becoming a "major trend[ ] in epidemiology over the past 10 years." See Luepker Supp., ECF No. 426-5 at 3. Dr. Luepker also failed to meaningfully examine the background risk of pathological gambling and other impulse control problems in either the general or psychiatric patient populations. Although Dr. Luepker expressed "some hesitation" and "worry" about Dr. Potenza's background risk estimates, he did not attempt to independently verify the accuracy of those figures. See Luepker Dep., ECF No. 462-1 at 118-19. Since the aim of epidemiology is to "identif[y] agents that are associated with an increased risk of disease," the Court would expect a more robust background risk analysis from an expert epidemiologist. See Ref. Man. at 552. Equally, if not more troubling is Dr. Luepker's opinion that a published case series, and even a single case report, are "definitely" types of epidemiological studies. See Luepker Dep., ECF No. 462-1 at 128. Both from a scientific perspective and for legal causation purposes, the distinction between epidemiological evidence and anecdotal evidence (i.e. , case series and case reports) is substantial and consequential. Dr. Luepker, apparently, disagrees.
There are also Daubert reliability problems with Dr. Luepker's general causation analysis. First, he employed the WHO-UMC causality criteria, which, as the Court has already discussed, see Section (II)(D)(1)(c)(ii), is a scientific tool designed to assess specific causation, see WHO-UMC Reference at 1. It "cannot" be used to prove general causation. See id. Second, Dr. Luepker's explanation of the biological mechanism by which Abilify can cause impulse control problems is inadequate, likely because much of the subject matter is, by his own admission, beyond the scope of his expertise.
Taken together, these are not insignificant failings and they cannot be cured by the fact that Dr. Luepker's conclusions are consistent with those of Plaintiffs' other experts. See In re Polypropylene Carpet Antitrust Litig. ,
e. David Madigan, Ph.D.
Dr. David Madigan is a biostatistician with over thirty years of experience researching, publishing, teaching, and consulting in the fields of statistics, biostatistics, epidemiology, and pharmacovigilance. He is offered for the purposes of providing: (1) a biostatistical analysis of the scientific evidence in this case; (2) background and contextual information about pharmacovigilance practices, as well as the design and analysis of clinical trials; and (3) a medical causation opinion that Abilify is capable of causing the specific adverse effects of pathological gambling and impulse control disorder. Defendants challenge Dr. Madigan on qualification and reliability grounds.
i. Qualification
Defendants argue that Dr. Madigan lacks the medical knowledge and experience to offer a general causation opinion. The Court agrees. "Dr. Madigan is a man of statistics, not medicine." See Def. Madigan Motion, ECF No. 427-20 at 9. He is not a medical doctor, toxicologist, pharmacologist, or psychologist. He also has no specialized knowledge of, or clinical experience with, pathological gambling or impulse control disorders. The Court finds that Dr. Madigan's admitted lack of expertise in the aforementioned fields precludes him from offering a medical or scientific opinion that Abilify is capable of causing pathological gambling and impulse control disorder.
Nevertheless, the Court finds Dr. Madigan amply qualified to offer a biostatistical analysis of the evidence in this case, as well as opinions related to pharmacovigilance and clinical trials generally, as his credentials in these fields are well beyond reasonable challenge. Briefly, Dr. Madigan is a Professor of Statistics at Columbia University, where he is also Dean of the Faculty and Executive Vice-President for Arts and Sciences. He holds a bachelor's *1362degree in Mathematical Sciences and a doctorate in Statistics. He is an elected Fellow of both the Institute of Mathematical Sciences and the American Statistical Association. He has published more than 160 peer-reviewed academic articles in the areas of statistics, biostatistics, epidemiology, and pharmacovigilance. Drug safety, with a focus on the development and application of statistical methods for pharmacovigilance, is a "significant research interest" of Dr. Madigan's. See Madigan Rep., ECF No. 427-1 at 2. Over the years, he has served the FDA in a number of different capacities related to the identification and evaluation of safety risks of medical products, and he currently serves the FDA as a consultant.
Defendants do not dispute that Dr. Madigan is a leading expert on biostatistics, pharmacovigilance, and clinical trials. Indeed, Dr. Madigan has been qualified to offer expert opinions in these areas in numerous federal and state courts.
ii. Dr. Madigan's Opinion
Dr. Madigan used a series of different statistical analyses to assess whether and to what extent the evidence in this case indicates the presence of an association between Abilify, pathological gambling, and impulse control disorders. The Court has already discussed Dr. Madigan's statistical analysis of the Etminan Study and his opinion that the Study evidences a "strong" association between Abilify and these two adverse effects. See supra Section II(C).
Dr. Madigan also conducted several disproportionality analyses of the FDA's adverse event reporting database (FAERS), comparing the relative frequency of pathological gambling reports among Abilify and 10 other atypical antipsychotics.
*1364Next, Dr. Madigan analyzed Defendants' clinical trial materials related to pathological gambling. He found that the clinical trials results reflected no patient reports of pathological gambling, so he analyzed the underlying trial data to determine whether the trial was sufficiently powered-essentially, whether it was large enough-to detect a statistically significant association between Abilify and pathological gambling, if in fact such an association existed.
Dr. Madigan also analyzed [* * * REDACTED * * *] . Dr. Madigan first calculated the frequency of these three categories of adverse effects in patients exposed to Abilify as compared with the frequency of those effects with comparator drugs and a placebo. This analysis yielded, in statistical terms, an estimate of the relative risk of developing the adverse effect among the three groups.
*1365Based on Dr. Madigan's calculations, [* * * REDACTED * * *] . Dr. Madigan testified that the other five p -values, although not statistically significant, still indicate that the probability that chance alone explains the other relative risk ratios is "very slim." See Madigan Tr., ECF No. 596-4 at 37. [* * * REDACTED * * *] . According to Dr. Madigan, although the corresponding p -value, 0.08, is not statistically significant, it is still relevant because it indicates that the likelihood of the 2.7 relative risk being explained by chance is only 8%.
iii. Reliability
Defendants challenge the reliability of Dr. Madigan's methodology on multiple grounds.
Defendants first challenge Dr. Madigan's expert opinions on the grounds that his initial expert report offers "no discernible methodology" as to how he reached his conclusions and that, at any rate, his opinions are not supported by any of the methodologies-epidemiology, dose-response, and background risk-that the Eleventh Circuit considers "indispensable" for proving that a drug can cause an adverse effect.
Dr. Madigan's opinions are very clearly based on the application of widely accepted statistical methods to data drawn from the "indispensable" field of epidemiology (i.e. , the Etminan Study), the FAERS database, and Defendants' clinical trials. See Madigan Rep., ECF No. 427-1 at 2-30; Madigan Supp., ECF No. 427-1 at 79-92.
Defendants also raise arguments regarding Dr. Madigan's analysis of their clinical trial data. First, they challenge as "pure speculation" Dr. Madigan's opinion that the clinical trials were not powered to detect a statistically significant increased risk of pathological gambling, which Defendants appear to claim is based solely on his observation that placebo subjects in the trials had no reports of pathological gambling. The premise of this argument is incorrect. When a study, such as the randomized clinical trials in this case, fails to find a statistically significant association between a drug and an adverse effect, an "important question is whether [that] result tends to exonerate the [drug's] toxicity or is essentially inconclusive with regard to toxicity." See Ref. Man. at 582. A statistical power analysis is a well-established scientific means of evaluating whether the study's outcome is exonerative or inconclusive. See
Finally, Defendants challenge as unreliable Dr. Madigan's use of five statistically insignificant data points as the basis for his opinion that the clinical trials show a *1367"concerning trend" of increased risk of impulsive behaviors with Ability patients.
In this case, the strength of Dr. Madigan's opinions lies in the statistical context they provide, which is based primarily on his assessments of the statistical significance of various categories of scientific evidence. For example, Dr. Madigan's defense of the Etminan Study is premised, in large part, on its "highly statistically significant results." See Madigan Rep., ECF No. 427-1 at 30. Similarly, according to Dr. Madigan, the statistically significant percentages of pathological gambling reports in the FAERS database evidence their "very strong" association with Abilify. See Madigan Tr., ECF No. 596-4 at 23-24. Dr. Madigan cannot now, with respect to the statistically insignificant "trends" in the clinical trial data, abandon statistical significance as a measure of reliability without a thorough explanation of why doing so is sound and supportable scientific practice. See Lipitor ,
In sum, Defendants' Motion to Exclude the General Causation Opinion of David Madigan, ECF No. 427-20, is due to be granted in part and denied in part. Dr. Madigan may not offer an expert opinion *1368on medical causation and also may not testify about the five statistically insignificant p -values he calculated from the clinical trial data. In all other respects, his expert opinion is admissible.
2. Defendants' Experts
Plaintiffs have moved to exclude the opinions of Defendants' five proposed experts-Drs. Blier, Leiderman, Potenza, Weed, and Winstanley-on multiple grounds. With respect to Drs. Blier, Potenza, and Weed, the Court has carefully considered Plaintiffs' arguments and finds them to be lacking in merit.
The Court next addresses, in turn, the admissibility of the proposed expert testimony of Drs. Leiderman and Winstanley.
a. Deborah B. Leiderman, M.D., M.A., FAAN
Dr. Deborah B. Leiderman is a licensed physician and board-certified neurologist. She has extensive experience in clinical research, as well as drug development, regulation and policy, including just over seven years at the FDA as the Director of the Controlled Substances Staff, during which time she served as the agency's *1369"lead physician and official on issues related to the Controlled Substances Act, abuse liability assessment, and domestic international drug scheduling and prescription drug abuse." Leiderman Rep., ECF No. 420-3 at 2-3.
The main thrust of Dr. Leiderman's opinions is that the FDA warning label and Pharmacovigilance Review concerning Abilify"do not support the conclusion that Abilify causes compulsive behaviors or impulse control disorders."
With respect to Dr. Leiderman's opinions, the Court finds that she may testify to the purpose behind the FDA's pharmacovigilance process and how it is conducted; however, she may not testify about language in a warning label or pharmacovigilance review unless her testimony is supported by a specific FDA regulation, rule, policy, or official agency guidance (e.g. , FDA Pharm. Guide, DX-15). In other words, Dr. Leiderman may not simply read FDA materials to the jury and then testify to what the FDA meant or intended by including or excluding certain language.
b. Catharine A. Winstanley, Ph.D.
Dr. Catharine Winstanley is a professor in the psychology department at the University of British Columbia. She holds an undergraduate degree in psychology and physiology, as well as a doctorate in behavioral neuroscience. She has extensive professional experience in the design and use of in vivo studies of "impulsivity and risky decision-making" in rodents to investigate and understand these conditions in humans. See Winstanley Rep., ECF No. 461-1 at 2.
As to Dr. Winstanley's qualifications, the Court agrees that she is not qualified to *1371offer a comprehensive general causation opinion. She is not a medical doctor, toxicologist, pharmacologist, or epidemiologist, and she has no specialized knowledge of, or clinical experience with, Abilify, pathological gambling, or impulse control disorders in humans. Dr. Winstanley's admitted lack of expertise in the aforementioned areas precludes her from offering a medical or scientific opinion that Abilify cannot cause impulse control problems. However, given Dr. Winstanley's knowledge and experience with animal models of impulsivity, the Court finds her qualified to offer an expert opinion regarding any such evidence that is ultimately deemed admissible in this case.
Dr. Winstanley's opinion is based on her review of in vivo studies investigating impulse control and gambling-related behavior in rodents, studies that she considers contradictory to Plaintiffs' experts' opinions regarding the biological mechanism by which Abilify can cause gambling and impulsivity problems in humans. See Winstanley Tr., ECF No. 596-8 at 107.
Dr. Winstanley testified that it is "impossible" to translationally validate any model of gambling disorder in rodents and that, to her knowledge, Abilify has never been tested in any rodent models of gambling-related behavior. See Winstanley Tr., ECF No. 596-8 at 99, 108. Therefore, to the extent she has extrapolated from the in vivo studies in this case any conclusions about gambling disorder or gambling-related behavior in humans, the Court finds those conclusions inadmissible at trial. Dr. Winstanley also offers opinions based on the findings of in vivo studies involving drugs that are pharmacologically different from Abilify.
E. Conclusion
When ruling on challenges to expert testimony under Rule 702 and Daubert , the Court is charged with the responsibility of acting as a gatekeeper, excluding "junk science" and other unreliable information, see Joiner ,
In this case, Plaintiffs have shown, by a preponderance of the evidence, that their general causation evidence is sound and reliable. For starters, there is reliable evidence of a broad scientific consensus regarding the existence of an association between Abilify and increased risk of impulse control problems.
III. Summary Judgment
Defendants have moved for summary judgment on general causation under Daubert based on Plaintiffs' lack of admissible expert testimony. Because the Court has found that most of Plaintiffs' evidence on general causation-including epidemiology (i.e. , Etminan Study), background risk, biological plausibility, disproportionality analyses, in vivo and in vitro studies, voluminous case and adverse event reports (including dose-response, dechallenge, and rechallenge events), FDA materials, Defendants' investigative findings, and Plaintiffs' experts' Bradford Hill and weight-of-the-evidence analyses-satisfies Rule 702 and Daubert , there exists a genuine dispute of material fact on the issue of whether Abilify can cause uncontrollable impulses in individuals taking the drug. Therefore, Defendants' Motion for Summary Judgment on General Causation, ECF No. 428, is due to be denied.
Accordingly, it is ORDERED :
1. Plaintiffs' Daubert Motion to Exclude the Testimony of Defendants' Expert Marc N. Potenza, ECF No. 415, is DENIED .
2. Plaintiffs' Daubert Motion to Exclude the Testimony of Pierre Blier, M.D., Ph.D., ECF No. 418, is GRANTED in part and DENIED in part, as discussed in the body of this Order.
3. Plaintiffs' Daubert Motion to Exclude the Testimony of Defendants' Expert Douglas Weed, M.D., ECF No. 419, is GRANTED in part and DENIED in part, as discussed in the body of this Order.
4. Plaintiffs' Daubert Motion to Exclude the Testimony of Defendants' Expert Deborah B. Leiderman, M.D., M.A., FAAN, ECF No. 420, is GRANTED in part and DENIED in part, as discussed in the body of this Order.
*13745. Plaintiffs' Daubert Motion to Exclude the Testimony of Defendants' Expert Catharine Winstanley, Ph.D., ECF No. 422, is GRANTED in part, DENIED in part, and DEFERRED in part, as discussed in the body of this Order.
6. Defendants' Motion to Exclude the General Causation Opinion of Antoine Bechara, ECF No. 423, is GRANTED in part and DENIED in part, as discussed in the body of this Order.
7. Defendants' Motion to Exclude the General Causation Opinion of Joseph Glenmullen, ECF No. 424, is GRANTED in part and DENIED in part, as discussed in the body of this Order.
8. Defendants' Motion to Exclude the General Causation Opinion of Eric Hollander, ECF No. 425, is DENIED .
9. Defendants' Motion to Exclude the General Causation Opinion of Russell Luepker, ECF No. 426, is GRANTED .
10. Defendants' Motion to Exclude the General Causation Opinion of David Madigan, ECF No. 427, is GRANTED in part and DENIED in part, as discussed in the body of this Order.
11. Defendants' Motion for Summary Judgment on General Causation Based on Plaintiffs' Lack of Admissible Expert Testimony Under Daubert, ECF No. 428, is DENIED .
SO ORDERED , on this 15th day of March, 2018.
The Court will use these terms interchangeably.
In its pharmacovigilance review of Abilify, the United States Food and Drug Administration ("FDA"), defined "impulse control disorders" to include "pathological gambling (PG; also known as gambling disorder or compulsive gambling), compulsive sexual behavior (i.e. , hypersexuality or sexual addiction), compulsive buying/shopping (i.e. , shopping addiction), and compulsive eating (i.e. , binge eating)." See FDA Pharm. Vigil., ECF No. 428-11 at 5. The FDA's pharmacovigilance review is discussed more fully in the body of this Order.
There are ten motions to exclude experts currently pending. Plaintiffs move to exclude the opinions of Defendants' five expert witnesses: Marc N. Potenza, ECF No. 415; Pierre Blier, ECF No. 418; Douglas Weed, ECF No. 419; Deborah B. Leiderman, ECF No. 420; and Catharine Winstanley, ECF No. 422. Defendants move to exclude the general causation opinions of Plaintiffs' five expert witnesses: Antoine Bechara, ECF No. 423, Joseph Glenmullen, ECF No. 424, Eric Hollander, ECF No. 425, Russell Luepker, ECF No. 426, and David Madigan, ECF No. 427. In this Order, "DX-" refers to Defendant's exhibits at the Daubert hearing and "PX-" refers Plaintiffs' exhibits at the hearing.
"Master Complaint" refers to Plaintiffs' Master Form Complaint and Jury Demand, ECF No. 108-1.
"DSJ" refers to Defendants' Motion for Summary Judgment on General Causation, ECF No. 28-26.
The European Medicines Agency is an international public health agency charged with the scientific evaluation, supervision and safety monitoring of medicines for the European Union. See http://www.ema.europa.eu/ema/. Abilify's European label history may be found at: http://www.ema.europa.eu/docs/en_GB/document_library/Other/2012/10/WC500134109.pdf.
"FDA Pharm. Vigil." refers to the FDA's Abilify Pharmacovigilance Review dated March 10, 2016, ECF No. 428-11 at 5.
Health Canada, Safety Information for Antipsychotic Drug Abilify and Risk of Certain Impulse-Control Behaviors (Nov. 2, 2015), http://healthycanadians.gc.ca/recall-alert-rappel-avis/hc-sc/2015/55668a-eng.php. Health Canada is Canada's national public health agency. See https://www.canada.ca/en/health-canada/corporate/about-health-canada.html.
The FDA's adverse event reporting system, known as FAERS, contains information on adverse event and medication error reports submitted to the FDA by patients, health care professionals, and pharmaceutical companies.
FDA Drug Safety Communication: FDA Warns About New Impulse-Control Problems Associated with Mental Health Drug Aripiprazole (Abilify, Abilify Maintena, Aristada) ; https://www.fda.gov/Drugs/DrugSafety/ucm498662.htm (last visited Dec. 3, 2017).
This biochemistry discussion is grounded in undisputed expert testimony and reports presented by both sides.
The neuron sending the message is called the presynaptic cell. The neuron receiving the message is called the postsynaptic cell.
The major neurotransmitters include acetylcholine, adrenaline, dopamine, endorphins, GABA, glutamate, norepinephrine, and serotonin.
The Nigrostriatal Pathway covers movement and sensory stimuli. The Mesocortical Pathway covers cognition, memory, attention, emotional behavior, and learning. The Mesolimbic Pathway regulates pleasure, reward processing, and motivation. The Tuberoinfudibular Pathway controls the hypothalamic pituitary endocrine system, and inhibition of prolactin secretions.
This is true except in the small number of cases where the medical community recognizes and agrees that a particular substance is toxic, in which case, general causation is accepted. See Chapman ,
Biological plausibility is also referred to as a "plausible biological mechanism of action."
Epidemiologists use clinical trials, cohort studies, case-control studies, cross-sectional studies, and/or ecological studies to determine whether exposure increases the risk of developing a particular disease or adverse effect, by comparing individuals exposed to a particular agent with unexposed individuals. Ref. Man. at 555-63.
Sir Austin Bradford Hill was a world-renowned epidemiologist who articulated a nine-factor set of guidelines that is widely accepted in the scientific community for determining whether an observed association between an agent and a disease reflects a true causal relationship. See Ref. Man. at 600; see also Austin Bradford Hill, The Environment and Disease: Association or Causation? , 58 Proceedings Royal Soc'y Med. 295 (1965) ("Bradford Hill Article"), ECF No. 460-4.
Inherent biases may include selection bias, conceptual bias, referral bias, or over-reporting of symptoms. See Barrow v. Bristol-Myers Squibb Co. , No. 6:96-cv-689,
Physicians and patients are encouraged to report such events voluntarily, whereas drug manufacturers are required to do so. See, e.g. ,
See also United States Food and Drug Administration, Guidance for Industry: Good Pharmacovigilance Practices and Pharmacoepidemiologic Assessment (March 2005) at 9, https://www.fda.gov/downloads/drugs/guidancecomplianceregulatoryinformation/guidances/ucm071696.pdf (last visited Dec. 3, 2017) ("FDA Pharm. Guide").
The term "in vivo " encompasses studies conducted on any living organisms, including human subjects. Kilpatrick ,
The Study's lead author, Dr. Mahyar Etminan, was not called as a witness at the Daubert hearing and has not been offered as an expert. However, the Court allowed Defendants to depose Dr. Etminan because of the Study's importance in this case, given that it is the only epidemiological study to date analyzing the connection between Abilify and impulse control disorders, including pathological gambling.
The Etminan Study had six co-authors: Dr. Mahyar Etminan, Mohit Sodhi, Dr. Ric M. Procyshyn, Michael Guo, and Dr. Bruce C. Carleton. See Etminan Study, ECF No. 428-13 at 1.
Plaintiffs' expert, Dr. Joseph Glenmullen, characterized another study, referred to as the Moore Study, as an epidemiological study. See Thomas J. Moore et al., Reports of Pathological Gambling, Hypersexuality, and Compulsive Shopping Associated with Dopamine Receptor Agonist Drugs , 174 JAMA Internal Med. 1930, 1930-33 (2014) ("Moore Study"), ECF No. 428-10 at 2-5. Despite Plaintiffs' insistence to the contrary, see Plaintiffs' Glenmullen Opposition, ECF No. 457-13 at 23, the Moore Study is not an epidemiological study. It is a disproportionality analysis. See Moore Study, ECF No. 428-10 at 2 (The Moore Study "conducted a disproportionality analysis based on ... adverse drug event reports ... extracted from the FDA Adverse Event Reporting System.") (emphasis added).
The purpose of an epidemiological case-control study is to determine whether exposure to a drug is associated with a particular outcome (i.e. , a disease or adverse effect). See Ref. Man. at 559. Researchers identify a group of individuals who have a disease ("cases") and a group of similar individuals who do not have the disease ("controls"). See
"ICD-9-CM Codes" refers to the diagnostic and procedure codes established in the International Classification for Disease, Ninth Edition, Clinical Modification.
There were 355 diagnoses coded as 312.31, which represents pathological gambling, and 4,341 diagnoses coded as 312.3, which represents impulse control disorders. See Etminan Study, ECF No. 428-13 at 1-2.
The Etminan Study selected 10 controls for every case. See Etminan Study, ECF No. 428-13 at 1. Individuals in the control groups were similar to individuals in the case groups with respect to age, gender, follow-up time, and calendar time. See
As the Fifth Circuit has explained,
the confidence interval tells one that if repeated samples were drawn from [a population] in the same ways as the instant sample was drawn, the means of the samples drawn would fall within the confidence interval a certain percentage, say 95 percent, of the time. On the basis of this information, researchers customarily conclude that the true means of the [population] falls within the confidence limits.
Univ. Computing Co. v. Mgm't Sci. Am., Inc. ,
Biostatistics is a specialty within the field of statistics that involves the application of statistical methods to a wide range of issues in biology, medicine, and public health.
For the reasons discussed more fully in Section II(D)(1)(d) of this Order, the Court finds Dr. Madigan qualified to offer an opinion on the statistical reliability of the Etminan Study.
See, e.g. , Gianluca Trifirò & Janet Sultana, The Role of Health Care Databases in Pharmacovigilance of Psychotropic Drugs , in Pharmacovigilance in Psychiatry 73, 90 (Edoardo Spina & Gianluca Trifirò eds., 2016) ("[A]dministrative/claims databases are important data sources to carry out observational studies aimed at quantifying and describing emerging safety issues associated with the use of psychotropic drugs, as shown by the large amount of database safety studies that have been published worldwide in the last decades."), DX-127 at 18; Esther W. Chan et al., Adverse drug reactions-examples of detection of rare events using databases , 80:4 Brit. J. Clin. Pharmacology 855, 855 (2014) ("Large databases provide an important platform for the undertaking of observational studies to generate clinical data on the effectiveness and safety of drugs."), ECF No. 463-6 at 2; Sebastian Schneeweiss & Jerry Avorn, A Review of Uses of Health Care Utilization Databases for Epidemiologic Research on Therapeutics , 58 J. Clin. Epidemiology 323, 323-25 (2005) ("[L]arge health care databases" are "a useful data source for researchers and regulatory agencies to study the safety of drugs."), DX-122 at 1-3.
Defendants raise several scattered arguments arising from this limitation, such as the Etminan Study's inability to: (1) precisely identify the date of onset of pathological gambling or impulse control disorders ; (2) verify the medical accuracy of any diagnosis; and (3) ensure against data entry errors, such as inaccurate diagnosis coding. The Court has carefully considered these arguments and finds them lacking in merit, for the reasons more fully stated in the body of this Order. In short, the arguments reflect on the Etminan Study's probativeness, not its admissibility. See Daubert ,
At his deposition, Dr. Etminan testified that he has, in the past, used a "buffer" around the prescription date to account for the time it takes patients to fill a prescription, take the medication and develop the disease. See Etminan Dep., ECF No. 428-12 at 13. The record includes only one study in which Dr. Etminan employed this "buffer" technique. See Mahyar Etminan et al., Oral Contraceptives and the Risk of Gallbladder Disease: A Comparative Safety Study , 183 Can. Med. Ass'n J. 899 (2011), PX-125. In another published study, Dr. Etminan used two prescriptions as a proxy for exposure on the theory that multiple dispensings increases the likelihood that a patient is actually taking the drug. See Mahyar Etminan, Pharmacoepidemiology II: The Nested Case-Control Study-A Novel Approach in Pharmacoepidemiologic Research , 24 Pharmacotherapy 1105 (2004), ECF No. 428-14 at 2.
See Mahyar Etminan et al., Risperidone and Risk of Gynecomastia in Young Men , 25 J. Child & Adolescent Psychopharmacology 671, 672 (2015) (defining "any use" of the drug as "the use of at least one prescription in the year before the index date"), PX-145; Mahyar Etminan et al., Isotretinoin and Risk for Inflammatory Bowel Disease: A Nested Case-Control Study and Meta-analysis of Published and Unpublished Data , 149 JAMA Dermatology 216, 217 (2013) (defining drug "use" as "at least [one] dispensed prescription for [the drug] regardless of dosage during the 365 days before the first IBD claim (and in corresponding calendar time for controls)"), PX-126; Mahyar Etminan et al., Testosterone Therapy and Risk of Myocardial Infarction: A Pharmacoepidemiologic Study , 35 Pharmacotherapy 72, 73 (2015) (defining testosterone use as having "filled at least one prescription for [testosterone replacement therapy] within [one] year before the index date"), PX-167; Mahyar Etminan et al., Use of Oral Bisphosphonates and the Risk of Aseptic Osteonecrosis: A Nested Case-Control Study , 35 J. Rheumatology 691, 692 (2008) ("Current users were defined as those who received at least one prescription for a bisphosphonate within 90 days of the index date."), PX-124.
"Potenza Tr." refers to the redacted version of the official transcript of Dr. Marc Potenza's testimony at the Daubert hearing, ECF Nos. 596-6 at 22-72, 596-7 at 3-89.
"Hollander Tr." refers to the redacted version of the official transcript of Dr. Eric Hollander's testimony at the Daubert hearing, ECF Nos. 596-4 at 108, 596-5.
"DSM-5" refers to the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (5th ed. 2013).
The International Classification of Disease ("ICD") is the official international classification system, intended to provide a standardized means of documenting, tracking, and billing for medical diagnoses and diseases worldwide. See DSM-5 at 10-11. The DSM, which is used primarily in the United States, provides health care professionals with strict criteria and definitions to aid in the clinical diagnosis and treatment of mental disorders. See DSM-5 at xii.
It bears repeating that the DSM-5 does not reject the existence or legitimacy of iatrogenic gambling as a "separate and distinct" medical diagnosis, which Defendants seem to suggest. See Def. Potenza Opposition, ECF 458-6 at 6-7. In fact, it does exactly the opposite. The DSM-5 provides that "[s]ome patients taking dopaminergic medications (e.g. , for Parkinson's disease ) may experience urges to gamble. If such symptoms dissipate when dopaminergic medications are reduced in dosage or ceased, then a diagnosis of gambling disorder would not be indicated." See DSM-5 at 589, ECF No. 428-3 at 68. The medical term "dopaminergic" means "liberating, activated by, or involving dopamine." See Merriam-Webster Online Medical Dictionary, https://www.merriam-webster.com/dictionary/dopaminergic (retrieved Dec. 3, 2017). Because its mechanism of action involves dopamine, Abilify is clearly a dopaminergic medication. The parties' experts agree. See Blier Tr., ECF No. 596-8 at 15 (conceding all drugs that work on dopamine "technically" are dopaminergic drugs); Hollander Tr., ECF No. 596-4 at 140 (stating that Abilify is a dopaminergic medication).
Defendants make much of their claim that five diagnoses of pathological gambling is too small a number to reliably demonstrate the requisite association in this case. Plaintiffs' biostatistician, Dr. Madigan, explains this by reference to the confidence interval. See Madigan Tr., ECF No. 596-4 at 53. More specifically, Dr. Madigan testified that the number of adverse medical events is not the relevant inquiry for statistical purposes; rather, the focus is on the lower bound of the confidence interval, which in this case, is substantially greater than 1.0. See Madigan Rep., ECF No. 427-1 at 25. This means that the Etminan Study's findings are statistically significant. In any event, nothing in the published scientific literature criticizes the Study on this basis.
"Technically, a standard deviation is defined as a measure of spread, dispersion, or variability of a group of numbers equal to the square root of the variance of that group of numbers." Stagi v. National R.R. Passenger Corp. ,
Defendants mischaracterize Dr. Etminan's testimony as a definitive statement that the standard deviation of 17.4 days means at least one of the five patients was diagnosed three days after his exposure to Abilify. The Court does not read Dr. Etminan's testimony as unequivocal with respect to any minimum number of days. Dr. Etminan initially stated that, given the Study's standard deviation, the least amount of time between exposure and diagnosis was "[p]robably three days." See Etminan Dep., ECF No. 427-3 at 42. However, he immediately backpedaled and agreed only that diagnosis could occur "a matter of days" after exposure to Abilify. See
"Etminan Dep." refers to the official transcript of Dr. Mahyar Etminan's deposition testimony on May 16, 2017, ECF No. 427-3.
At the Daubert hearing, Dr. Madigan also offered a third distribution of time-to-diagnosis dates that he opines are consistent with the mean and standard deviation reported in the Etminan Study. Because this third calculation was not disclosed in Dr. Madigan's expert reports, Plaintiffs agreed to omit it from their argument under Daubert. See Madigan Tr., ECF No. 596-4 at 62.
"Madigan PPT" refers to the Powerpoint presentation used by Dr. Madigan at the Daubert hearing, PX-051.
Dr. Weed, who is Defendants' expert epidemiologist, testified that he did not attempt to calculate the possible distribution of time-to-diagnosis periods based on the mean and standard deviation reported in the Etminan Study. See Weed Tr., ECF No. 596-8 at 82. "Weed Tr." refers to the official transcript of Dr. Douglas Weed's testimony at the Daubert hearing, ECF No. 596-8.
See, e.g. , E. Peterson & R. Forlano, Partial Dopamine Agonist-Induced Pathological Gambling and Impulse-Control Deficit on Low-Dose Aripiprazole , 25 Australasian Psychiatry 614 (2017) (patient's "strong desire to gamble" developed "after only a few days on" Abilify ); L. Gaboriau et al., Aripiprazole : A New Risk Factor for Pathological Gambling? A Report of 8 Case Reports , 39 Addictive Behaviors 526, 563 (2014) (one patient's "strong urges to gamble" developed within days of starting Abilify treatment and another patient's "irresistible urge to gamble" developed within days after his Abilify dose was increased from 10 mg to 20 mg per day), ECF No. 425-7 at 2-5; Giles Gavaudan et al., Partial Agonist Therapy in Schizophrenia: Relevance to Diminished Criminal Responsibility , 55 J. Forensic Sci. 1659 (2010) (patient's pathological gambling symptoms began "a few days" after starting Abilify treatment), DX-631 at 1; M. Kodama & T. Hamamura, Aripiprazole-Induced Behavioral Disturbance Related to Impulse Control in a Clinical Setting , 13 Int'l J. Neuropsychopharmacology 549, 550 (2010) (patient's hypersexuality symptoms presented within the first week of taking Abilify ), DX-652 at 1; J. Schlachetzki & J. Langosch, Aripiprazole Induced Hypersexuality in a 24-Year-Old Female Patient with Schizoaffective Disorder ? , 28 J. Clinical Psychopharmacology 567 (2008) (patient's hypersexuality symptoms developed within "[a] few days" of taking Abilify ).
Defendants' notion that idiopathic gambling under the DSM-5 "takes up to twelve months to develop into a disease," DSJ, ECF No. 428 at 27, suggests a misunderstanding of the diagnostic criteria for the disorder. On its face, the DSM-5 requires only that an individual exhibit four or more problem gambling symptoms in a 12-month period. See DSM-5, ECF No. 428-3 at 64. Under this criterion, the symptoms may develop over 12 months, but they also could manifest within a single month. In either scenario, assuming the other criteria were met, a diagnosis of idiopathic gambling disorder would be appropriate.
"DSJ Reply" refers to Defendants' Reply in Support of their Motion for Summary Judgment on General Causation, ECF No. 484.
For example, researchers may conclude from a study that individuals with gray hair have a higher rate of death than those with hair of another color. Ref. Man. at 591. Instead of hair color having an impact on death, the results might be explained by the confounding factor of age. Id. If old age is associated differentially with the gray-haired group (those with gray hair tend to be older), old age may be responsible for the association found between hair color and death. Id. Thus, researchers would need to separate the relationship between gray hair and risk of death from that of old age and risk of death. Id.
These statistical analyses may include sensitivity analyses, stratification, and multivariate analysis. Ref. Man. at 593, 595-97. A sensitivity analysis is used to test whether and how the results of a study change if specific variables or assumptions are changed (i.e. , indicates whether the results are sensitive to certain variables or assumptions). See id. at 595-96. The Etminan Study, for example, included a sensitivity analysis restricted to patients with bipolar disorder. See Etminan Study, ECF No. 428-13 at 3. Stratification involves the use of statistical methods to combine the results of different exposure levels (or strata) to the confounding factor to arrive at one overall estimate of risk. See id. at 596-97. Multivariate analysis involves using mathematical modeling to "describe the simultaneous effect of exposure and confounding factors on the increase in risk." Id. at 597. The latter two methods modify an observed association to take into account the effect of risk factors are not the subject of the study and that may distort the exposure being studied and disease outcomes." Id.
This may be why Defendants direct the substance of their confounders argument at major depressive disorder, for which Abilifyis indicated as an adjunctive treatment for patients who are also using antidepressants.
A cross-sectional study is an epidemiological study in which exposure and an outcome or disease are measured at the same point in time in a given population. Ref. Man. at 560. Temporal and/or causal relationships between exposure and disease or outcome cannot be established through a cross-sectional study. Id. at 560-61.
The 11 atypical antipsychotics that the FDA analyzed were: aripiprazole, olanzapine, quetiapine, risperidone, asenapine, brexpiprazole, clozapine, iloperidone, lurasidone, paliperidone, and ziprasidone. FDA Pharm. Vigil., ECF No. 428-11 at 27.
No reported cases of pathological gambling occurred with asenapine, brexpiprazole, clozapine, iloperidone, lurasidone, paliperidone, and ziprasidone. Id.
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Dr. Etminan called Plaintiffs' counsel a second time in October 2016, after the Etminan Study had been selected for publication by the Journal of Clinical Psychopharmacology. See Etminan Dep., ECF No. 457-7 at 28. Plaintiffs' counsel again ended the conversation after telling Dr. Etminan that they could speak once the study was actually published. See id.
The Etminan Study was funded by the British Columbia Health Services Authority, a third-party Canadian health agency that is not involved in this litigation. See Etminan Study, ECF No. 428-13 at 1.
"Madigan Tr." refers to the redacted version of the official transcript of Dr. David Madigan's testimony at the Daubert hearing, ECF No. 596-4 at 4-107.
Dr. Procyshyn has served on advisory boards and speaker's bureaus for Otsuka. Etminan Study, ECF No. 428-13 at 4.
The suspect adverse reaction report indicates that the consumer "stopped taking his [Abilify ] after seeing the advertisement two or three days ago and said that his urge to gamble had stopped. At the time of the report, the consumer had not talked with his [health care provider] about stopping [Abilify ] treatment." ECF No. 460-13 at 2.
"Weed Supp." refers to Dr. Douglas L. Weed's Supplemental Expert Report, ECF No. 419-23 at 2-20.
Dr. Weed identified three case reports published in the medical literature in 2010, five published in 2011, and eight published in 2014. See Weed Supp., ECF No. 419-23 at 14.
Again, the Court separately analyzes Dr. Madigan's qualifications to offer expert opinions in this case, and also the reliability of his opinions with respect to other scientific evidence, in Section II(D)(1)(d).
Defendants also challenge Dr. Madigan's analysis of the Etminan Study on the grounds that he failed to properly address: (1) any potential confounders that were "not controlled for or otherwise addressed" in the Study, such as major depressive disorder ; (2) possible investigator bias; (3) potential misclassification bias, and (4) the rapid onset time for symptoms of pathological gambling in patients from the LifeLink database. The Court has carefully considered these arguments and finds them lacking in merit, for the reasons more fully stated in the body of this Order. In short, the arguments reflect only on the probative value of Dr. Madigan's opinion, not its admissibility.
See, e.g. , David Madigan et al., A Systematic Statistical Approach to Evaluating Evidence from Observational Studies , 1 Annual Review of Statistics and Its Application 11 (2014) ("Madigan 2014"), DX-117; David Madigan et al., Empirical Performance of the Case-Control Method: Lessons for Developing a Risk Identification and Analysis System , 36 (Supp. 1) Drug Safety S73 (2013) ("Madigan 2013a"), ECF No. 427-6 at 2; David Madigan et al., Evaluating the Impact of Database Heterogeneity on Observational Study Results , 178 Am. J. Epidemiology 645 (2013) ("Madigan 2013b"), ECF No. 427-8 at 2.
The OMOP was originally managed by the Foundation for the National Institutes of Health ("FNIH"). On its completion in June 2013, the OMOP was transferred from FNIH to the Reagan-Udall Foundation for the FDA and became known as the Innovation in Medical Evidence Development and Surveillance program. See https://fnih.org/what-we-do/major-completed-programs/omop (last visited Dec. 3, 2017).
"Weed Rep." refers to Dr. Douglas L. Weed's Expert Report, ECF No. 419-3 at 2-78.
In his initial expert report, Dr. Weed stated that the Bradford Hill factors "are only applied ... once a statistical association has been established, i.e. once at least one (and typically several) epidemiological studies has revealed increased risks of a disease (or condition) that could be called "statistically significant," most often at the level of (p < 0.05), whether evaluated using p -values or confidence intervals." See Weed Rep., ECF No. 419-3 at 21.
"Madigan Dep." refers to the official transcript of Dr. David Madigan's deposition testimony on June 28, 2017, ECF No. 427-1 at 94-238.
The Court notes that if Dr. Madigan had offered calibrated p -values in support of his opinion instead of traditional p -values, there undoubtedly would have been reliability challenges to that methodology.
Dr. Joseph Glenmullen's expert report ("Glenmullen Rep."), ECF No. 424-1 at 1-137, 88-90, 103-04, 134 (compiling case and adverse events reports involving a "dose-dependent" relationship between Abilify, pathological gambling, and other impulse control disorders ); Dr. Eric Hollander's Initial General Causation Report ("Hollander Rep."), ECF No. 459-1 at 30-31 (same); Dr. David Madigan's Rebuttal Report ("Madigan Rep."), ECF No. 427-1 at 79-92, 83 (referencing FDA discussion of case and adverse event reports involving dose response relationship).
See Glenmullen Rep., ECF No. 424-1 at 88-90, 103-04 (collecting case studies).
U.S. Dep't of Health and Human Serv., FDA, Guidance for Industry: Exposure-Response Relationships-Study Design, Data Analysis, and Regulatory Applications (April 2003), https://www.fda.gov/downloads/drugs/guidancecomplianceregulatoryinformation/guidances/ucm 072109.pdf (last visited Dec. 3, 2017) ("FDA Dose-Response Guide").
See, e.g. , L. Gaboriau et al., Aripiprazole: A New Risk Factor for Pathological Gambling? A Report of 8 Case Reports , 39 Addictive Behaviors 526, 563 (2014) ("irresistible urge to gamble" developed "immediately" after Abilify daily dose increased from 10 mg to 20 mg per day; urges stopped after dose decreased to 15 mg); Milton G. Roxanas, Pathological Gambling and Compulsive Eating Associated with Aripiprazole , 44 Australian & New Zealand J. Psychiatry 291 (2010) (urges to gamble and eat developed six months after daily dose of Abilify was increased from 10 mg to 15 mg; urges stopped one month after discontinuing Abilify ).
The Court is aware that at least one district court in this Circuit appears to have considered "dechallenge-rechallenge reports" to be reliable, primary evidence of a dose-response relationship under Daubert. See In re Chantix (Varenicline) Prods. Liab. Litig. ,
See DSM-5 at 587, ECF No. 428-3 at 66.
See Dr. Antoine Bechara's Expert Report, ECF No. 423-1; Dr. Joseph Glenmullen's Expert Report, ECF No. 424-1 at 38-56; Dr. Eric Hollander's Expert Report, ECF No. 425-1 at 9-11, 13-19; Dr. Russell V. Luepker's Expert Report, ECF No. 462-1 at 6-7.
"Bechara Rep." refers to Dr. Antoine Bechara's Expert Report, ECF No. 423-1.
The Court separately analyzes Dr. Bechara's qualifications to offer expert opinions in this case in Section II(D)(1)(a).
"Bechara Tr." refers to the redacted version of the official transcript of Dr. Antoine Bechara's testimony at the Daubert hearing, ECF No. 596-1 at 74-168.
"Def. Bechara Motion" refers to Defendants' Motion to Exclude the General Causation Opinion on Antoine Bechara, ECF No. 423-10.
"Blier Dep." refers to the official transcript of Dr. Pierre Blier's deposition testimony on June 19, 2017, ECF No. 455-2 at 175-374.
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See also K. Maeda et al., Brexpiprazole I: In Vitro and In Vivo Characterization of a Novel Serotonin-Dopamine Activity Modulator , 350 J. Pharmacology & Experimental Therapeutics 589 (2014) (clinically effective dose range of Abilify leads to "80% to 90% D2receptor occupancy") ("Maeda 2014"), DX-062; Takashi Hamamura et al., Intrinsic Activity of Aripiprazole is Not 30% of Dopamine, But Only About 6% Under Ideal Antipsychotic Therapy , 69 J. Clinical Psychiatry 863, 843 (2008) ("Hamamura 2008") (same), DX-057 at 3; M. Kodama & T. Hamamura, Aripiprazole-Induced Behavioral Disturbance Related to Impulse Control in a Clinical Setting , 13 Int'l J. Neuropsychopharmacology 549, 550 (2010) ("Kodama 2010") ("Because [Abilify ] has a high affinity to D2receptors, about 90% of D2receptors are occupied [and blocked] by it."), ECF No. 453-17 at 3.
As the Court discussed in Section I of this Order, affinity is a measure of whether and how strongly a drug binds, or attaches, to a particular receptor. Affinity is distinct from intrinsic activity, which measures the degree to which the drug, once bound, activates dopamine receptors to produce a physiological effect.
Yoshihiro Tadori et al., Functional Potencies of Dopamine Agonists and Antagonists at Human Dopamine D2and D3Receptors , 666 European J. Pharmacology 43, 45 (2011) ("Tadori 2011a") (Abilify exhibiting more than three times higher affinity for D2than for D3), PX-021 at 3; see also Béla Kiss et al., Cariprazine (RGH-188), a Dopamine D3 Receptor-Preferring, D3/D2Dopamine Receptor Antagonist-Partial Agonist Antipsychotic Candidate: In Vitro and Neurochemical Profile , 333 J. Pharmacology & Experimental Therapeutics 328, 332 (2010) (Kiss 2010) (describing Abilify's higher affinity for D2than D3receptors); T. Hirose & T. Kikuchi, Aripiprazole, A Novel Antipsychotic Agent: Dopamine D2 Receptor Partial Agonist , 52 J. Medical Investigation Suppl. 284, 288 (2005) ("Hirose 2005") (describing Abilify's higher affinity for D2than for D3), DX-281 at 5.
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See, e.g. , Tadori 2011a at 43 ("Dopamine D3receptors are predominantly expressed in the nucleus accumbens"), PX-021 at 1; Kodama 2010 ("[T]he dopamine D3 receptor [ ] is highly enriched in the nucleus accumbens and plays an important role in reward."); Kiss 2010, 333 J. Pharmacology & Experimental Therapeutics at 328 ("Dopamine D3receptors ... are most abundant in the mesolimbic regions (i.e. , nucleus accumbens, island of Calleja")); Tadori 2008 at 30 ("[I]n humans, dopamine D3receptors are predominantly expressed in regions of the limbic striatum, including the nucleus accumbens."), DX-058 at 1; Gurevich & Joyce, Distribution of Dopamine D3Receptor Expressing Neurons in the Human Forebrain: Comparison with D2Receptor Expressing Neurons , 20 Neuropsychopharmacology 60, 64, 74 (1999) "Gurevich 1999") (finding the nucleus accumbens and ventral striatum "enriched" with "more abundant" concentrations of D3receptors than D2receptors); Murray et al., Localization of Dopamine D3 Receptors to Mesolimbic and D2 Receptors to Mesostriatal Regions of Human Forebrain , 91 Proceedings Nat'l Acad. Sci. U.S.A. 11271, 11274 (1994) (finding "high concentration" of D3receptors in the nucleus accumbens); see also FDA Pharm. Vigil., ECF No. 428-11 at 8 "[T]he D3dopamine receptor subtype is found predominantly in the limbic regions of the brain.").
See L. Descarries, et al., Dual Character, Asynaptic and Synaptic of the Dopamine Innervation in Adult Rat Neostriatum: A Quantitative Autoradiographic and Immunocytochemical Analysis , 375 J. Comparative Neurology 167, 183 (1996), DX-251 at 17 (stating that dopamine may spill or diffuse away from a synapse and activate dopamine receptors not located in precise apposition to the presynaptic neuron).
L. Gaboriau et al., Aripiprazole : A New Risk Factor for Pathological Gambling? A Report of 8 Case Reports , 39 Addictive Behaviors 562 (2014) (observing that upregulation and sensitization may "hyperstimulat[e]" D3receptors in Abilify patients, particularly those treated with antipsychotic dopamine antagonists in the past), ECF No. 428-8; Julien Cohen et al., Aripiprazole-Induced Pathological Gambling: A Report of 3 Cases , 6 Current Drug Safety 51 (2011) ("The appearance of [pathological gambling] in these [patients] could have been caused by the aberrant stimulation of the [meso-cortico-limbic] pathway by [Abilify ]."), ECF No. 428-6 at 4.
Yong Kee Choi et al., Long-term Effects of Aripiprazole Exposure on Monoaminergic and Glutamatergic Receptor Subtypes: Comparison with Cariprazine , 22 CNS Spectrums 484 (2017) (in vivo study finding chronic treatment with Abilify upregulated D2and D3receptor levels in rats, but did not increase D3receptors in shell of the nucleus accumbens); Jun Gao et al., Repeated Administration of Aripiprazole Produces a Sensitization Effect in the Suppression of Avoidance Responding and Phencyclidine-Induced Hyperlocomotion and Increases D2Receptor-Mediated Behavioral Function , 29 J. Psychopharmacology 390 (2015), DX-067 (in vivo study finding sensitization and upregulation of D2and D3receptors in rats treated with therapeutic dose of Abilify ).
To the contrary, the record indicates that many atypical antipsychotics are in fact antagonists at D3receptors. See Yoshiro Tadori et al., Characterization of Aripiprazole Partial Agonist Activity at Human Dopamine D3 Receptors , 597 European J. Pharmacology 27, 31 (2008) (in vitro study) ("Tadori 2008"), DX-58 at 5.
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"Def. Bechara Reply" refers to Defendants' Reply to Exclude the General Causation of Antoine Bechara, ECF No. 479-8.
Yoshihiro Tadori et al., Functional Potencies of Dopamine Agonists and Antagonists at Human Dopamine D2 and D3 Receptors , 666 European J. Pharmacology 43, 48 (2011) ("Tadori 2011a"), PX-021.
"Pl. Bechara Opposition" refers to Plaintiffs' Memorandum of Law in Opposition to Defendants' Motion to Exclude the General Causation Opinion of Antoine Bechara, ECF No. 453-32.
Presynaptic receptors, also called autoreceptors, provide a mechanism by which dopamine neurons regulate functions such the release and synthesis of dopamine.
Again, antagonists bind to dopamine receptors and produce no physiological effects. Partial agonists bind to dopamine receptors, but produce less of a physiological effect than endogenous dopamine would produce. Full agonists bind to dopamine receptors and mimic the activity of dopamine, producing the same level of physiological response that dopamine naturally produces.
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Yoshihiro Tadori et al., In Vitro Pharmacology of Aripiprazole, its Metabolite and Experimental Dopamine Partial Agonists at Human Dopamine D2 and D3 Receptors , 668 European J. Pharmacology 355, 357 (2011) ("Tadori 2011b") (exhibiting 54.9% and 43.9% intrinsic activity at human D3receptors), DX-061 at 3; Tadori 2011a at 48 (exhibiting 50.5% and 49.9% intrinsic activity at human D3receptors), PX-021 at 6; Tadori 2008 at 30 (exhibiting 51.2% and 47.8% intrinsic activity at human D3receptors), DX-058 at 4; Liesbeth A. Bruins Slot et al. , Action of Novel Antipsychotics at Human Dopamine D3 Receptors Coupled to G Protein and ERK1/2 Activation, 53 Neuropharmacology 232, 235 (2007) ("Bruins Slot 2007") (exhibiting 55% intrinsic activity at human D3receptors); Shapiro 2003 at 1401, 1408 (exhibiting both partial and full agonist actions at D3receptors), DX-045 at 2, 9.
Tadori 2011a at 48 (exhibiting no intrinsic activity at human postsynaptic D2receptors), PX-021 at 6; Yoshihiro Tadori et al., Differences in Agonist/Antagonist Properties at Human Dopamine D2 Receptors Between Aripiprazole, Bifeprunox and SDZ 208-912 , 574 European J. Pharmacology 103, 105 (2007) ("Tadori 2007") (exhibiting -2.8% intrinsic activity at human postsynaptic D2receptors), DX-056 at 3.
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"Bechara Supp." refers to Dr. Antoine Bechara's Supplemental Report, ECF No. 423-1 at 442-54.
See Cindy P. Lawler et al., Interactions of the Novel Antipsychotic Aripiprazole (OPC-14597) with Dopamine and Serotonin Receptor Subtypes , 20 Neuropsychopharmacology 612, 613, 622 (1999), DX-051 at 7 (stating that D2Sreceptors are preferentially expressed presynaptically); see also Tadori 2011b (showing 26.3% intrinsic activity at presynaptic D2Sreceptors), DX-061 at 3; Tadori 2011a (showing 25.5% intrinsic activity at presynaptic D2Sreceptors), PX-021 at 6; Yoshihiro Tadori, et al., Receptor Reserve-Dependent Properties of Antipsychotics at Human Dopamine D2 Receptors , 607 European J. Pharm. 35, 37 (2009) ("Tadori 2009") (exerting 31.9% intrinsic activity at presynaptic D2Sreceptors), DX-059 at 3; Tadori 2007 (exerting 17.2% intrinsic activity at presynaptic D2Sreceptors), DX-056 at 3; Lisbeth A. Bruins Slot, et al., Differential Profile of Antipsychotics at Serotonin 5-HT1Aand Dopamine D2S Receptors Coupled to Extracellular Signal-Regulated Kinase , 534 European J. Pharm. 534, 66 (2006) (exerting 58.7% intrinsic activity at presynaptic D2Sreceptors), DX-054 at 4; Yoshihiro Tadori, et al., Aripiprazole's Low Intrinsic Activities at Human Dopamine D2L and D2S Receptors Render It a Unique Antipsychotic , 515 European J. Pharm. 10, 14 (2005) (exerting 20% intrinsic activity at presynaptic D2Sreceptors) ("Tadori 2005"), DX-053 at 5.
Tadori 2011b (exerting 90.6% intrinsic activity at artificially high-density postsynaptic D2Lreceptors and 95.9% intrinsic activity at artificially high-density presynaptic D2Sreceptors), DX-061 at 3; Tadori 2011a (exerting 96.8% intrinsic activity at artificially high-density presynaptic D2Sreceptors), PX-021 at 6; Tadori 2009 (exerting 95.5% intrinsic activity at artificially high-density postsynaptic D2Sreceptors); Tadori 2007 (exerting 86% intrinsic activity at artificially high-density postsynaptic D2Lreceptors), DX-056 at 3; Tadori 2005 (exerting 76% intrinsic activity at postsynaptic D2Lartificially high-density postsynaptic D2Lreceptors), DX-053 at 5.
"Bechara Dep." refers to the official transcript of Dr. Antoine Bechara's deposition testimony on June 7, 2017, ECF No. 423-1 at 28.
See also Kent C. Berridge & Terry E. Robinson, What is the Role of Dopamine in Reward: Hedonic Impact, Reward Learning, or Incentive Salience? , 28 Brain Research Reviews 309 (1998).
The dopaminergic medications included sinemet (i.e. , L-DOPA), pramipexole (i.e. , Mirapex ), pergolide, amantadine, comtan, methylphenidate, and modafinil.
[* * * REDACTED * * *] . Defendants sought to exclude this internal communication, and others like it, because, in their view, while it may implicate issues of notice, it is not relevant to general causation. Plaintiffs disagreed, arguing that these materials do bear on general causation because many of them are authored by Dr. McQuade, who essentially led the research team that developed Abilify and whose observations about the drug thus are an integral, reliable part of the body of scientific evidence on its mechanism of action. The Court finds it unnecessary to consider Defendants' internal communications, including emails and meeting minutes, for purposes of this Order; therefore, Defendants' challenges to the admissibility of these materials are moot.
See, e.g. , L. Gaboriau et al., Aripiprazole: A New Risk Factor for Pathological Gambling? A Report of 8 Case Reports , 39 Addictive Behaviors 562 (2014) (eight case reports), ECF No. 428-8; EunJin Cheon et al., Two Cases of Hypersexuality Probably Associated with Aripiprazole , 10 Psychiatry Investigation 200 (2013) (two case reports), PX-07; Neil Smith et al., Pathological Gambling and the Treatment of Psychosis with Aripiprazole: Case Reports , 199 Brit. J. Psychiatry 158 (2011) (three case reports), ECF No. 428-7; Julien Cohen et al., Aripiprazole-Induced Pathological Gambling: A Report of 3 Cases , 6 Current Drug Safety 51 (2011) (three case reports), ECF No. 428-6; Giles Gavaudan et al., Partial Agonist Therapy in Schizophrenia: Relevance to Diminished Criminal Responsibility , 55 J. Forensic Sci. 1659 (2010) (two case reports), ECF No. 428-5; Milton G. Roxanas, Pathological Gambling and Compulsive Eating Associated with Aripiprazole , 44 Austl. & N.Z. J. Psychiatry 291 (2010) (one case report), ECF No. 428-4.
See, e.g. , Otsuka DA, PX-44 (discussing 236 post marketing spontaneous reports made to Bristol-Myers Squibb regarding pathological gambling in patients using Abilify ); FDA Pharm. Vigil., ECF No. 428-11 (discussing 167 FAERS case reports of impulse control related diagnoses, including pathological gambling, with Abilify use).
As discussed more fully in Section II(D)(1)(e), Dr. Madigan also performed disproportionality analyses of the FAERS database as of four different dates he considered significant in the life of this case. All four of his disproportionality analyses reflected statistically significant percentages of pathological gambling reports, which is consistent with the findings of the disproportionality analyses performed by both Otsuka and the FDA. See Section II(D)(1)(e).
Trilink Saw Chain, LLC v. Blount, Inc. ,
See supra Section II(B).
See supra n.19. Dr. Glenmullen also offers what he characterizes as dose-response evidence, but the Court has already found this evidence insufficient to establish the existence of a dose-response relationship. See supra Section II(C).
See also Kipperman v. Onex Corp. ,
At the Daubert hearing, Dr. Glenmullen testified that he has never diagnosed a patient with drug-induced pathological gambling. See Glenmullen Tr., ECF No. 596-2 at 136.
See, e.g., Chantix ,
Defendants also object to Dr. Glenmullen's qualifications to offer an expert opinion on "FDA regulations" and "FDA regulatory compliance." See Def. Glenmullen Opposition, ECF No. 424-15 at 13-14. Dr. Glenmullen has not been offered as an expert on FDA regulations or regulatory compliance, therefore this challenge is denied as moot. To the extent Defendant intended this objection to exclude Dr. Glenmullen's testimony regarding the FDA's disproportionality analysis of its adverse event reporting database, the challenge is denied for the same reasons he has been found qualified to testify on epidemiology.
Again, FAERS refers to the FDA's Adverse Event Reporting System. The Moore Study analyzed FAERS data, for the time period covering 2003 and 2012, for the following six dopamine receptor agonist drugs: Apomorphine, Bromocriptine, Cabergoline, Pramipexole, Ropinirole, and Rotigotine. See Moore Study at 1933, ECF No. 428-10 at 2. The 10 "impulsive" behaviors examined by the Moore Study were pathological gambling, hypersexuality, compulsive shopping, gambling, poriomania, binge eating, excessive masturbation, compulsive sexual behavior, kleptomania, and excessive sexual fantasies. See
For example, the Moore Study states that its "findings confirm and extend the evidence that dopamine receptor agonist drugs are associated with serious impulse control disorders ; the associations were significant, the magnitude of the effects was large, and the effects were seen for all 6 dopamine receptor agonist drugs. " See Moore Study at 1932, ECF No. 428-10 at 4 (emphasis added).
Dr. Glenmullen is one of the Moore Study's authors. See Moore Study at 1930, ECF No. 428-10 at 2.
"Def. Glenmullen Motion" refers to Defendants' Motion to Exclude the General Causation Opinion of Joseph Glenmullen, ECF No. 424-15.
This refers to the Etminan Study, which found a 5.23- and 7.71-fold increase in risk of gambling and impulsive control disorder diagnoses, respectively, for patients on Abilify, when compared to individuals not taking Abilify. See Etminan Study, ECF No. 428-13 at 2. Dr. Glenmullen also references the Moore Study, which the Court has found inadmissible.
This refers to several disproportionality analyses of the FAERS database related to Abilify, including: (1) the FDA Pharmacovigilance Report, which found a 6.3-fold increase in risk of pathological gambling reports associated with Abilify, as compared to all other atypical antipsychotics, see FDA Pharm. Vigil., ECF No. 428-11 at 27; (2) [* * * REDACTED * * *] and (3) [* * * REDACTED * * *] .
"Glenmullen Rep." refers to Dr. Joseph Glenmullen's Expert Report, ECF No. 424-1.
At the Daubert hearing, Defendants objected to Dr. Glenmullen's testimony regarding whether case reports exhibiting dechallenge and rechallenge events are caused by a placebo effect, arguing that the testimony was outside the scope of his expert report. See Glenmullen Tr., ECF No. 596-2 at 72. Defendants' objection on this basis is overruled, as the issue was sufficiently raised at Dr. Glenmullen's deposition. See Glenmullen Dep., ECF No. 424-1 at 206.
Psychopharmacology and neuropsychopharmacology are interrelated fields of study. Psychopharmacology is the study of how drugs affect mood, perception, thinking, and behavior. Neuropsychopharmacology is the study of how drugs affect the nervous system and how those nervous system changes alter behavior.
"Hollander Rep." refers to Dr. Eric Hollander's Expert Report, ECF No. 459-1.
For this reason, the Court overrules Defendants' Daubert hearing objections as to Dr. Hollander's testimony on both the history of the DSM-5 and the distinction made in the publication between idiopathic and iatrogenic gambling. Given his professional experience working on the DSM-5, and also his deposition testimony, these opinions are clearly within the scope of his expertise and his reports.
A "problem gambler" was defined as a patient who has exhibited three or more of the DSM-IV diagnostic criteria for "pathological gambling" in the preceding 12 months. See Grall-Bronnec Article, ECF No. 425-4 at 3. The Article's authors stated that, although the presence of at least five of the DSM-IV diagnostic criteria are required for a formal diagnosis of pathological gambling, the presence of at least three criteria is enough to suggest "at risk gambling" or "problem gambling." See
The dopamine replacement medications were cabergoline, pergolide, piribedil, pramipexole, ropinirole, levodopa, and carbidopa. See Grall-Bronnec Article, ECF No. 425-4 at 3.
"Def. Hollander Motion" refers to Defendants' Motion to Exclude the General Causation Opinion of Eric Hollander, ECF No. 425-14.
The Grall-Bronnec Article's authors identified 17 published case reports describing gambling behaviors in Abilify patients, eight of which involved individual patients who also participated in the in-person clinical evaluations. See Grall-Bronnec Article, ECF No. 425-4 at 4. The authors identified 42 published case reports describing gambling behaviors in patients taking dopamine replacement therapy, in addition to six such patients who participated in the in-person clinical evaluations. See
The authors also concluded it was "possible" that the gambling behaviors in 46 of the 48 dopamine replacement therapy cases "was actually due to" the dopamine replacement therapy. See id. at 4.
The same is true of the authors' in-person clinical assessments of the six patients taking dopamine replacement therapy.
Neither Dr. Hollander nor the Grall-Bronnec Article's authors characterized, or treated, this evidence as epidemiology.
The Naranjo Adverse Drug Reactions Probability Scale, also referred to as the Naranjo Scale or Naranjo Algorithm, is a scientific tool designed to assess the probability that a discrete adverse medical event was drug-induced, rather than the result of other factors. Christopher R.J. Pace, Admitting and Excluding General Causation Expert Testimony: The Eleventh Circuit Construct , 37 Am. J. Trial Advocacy 47, 61 n.60 (2013). Similarly, the Causality Assessment System of the World Health Organization-Uppsala Monitoring Centre ("WHO-UMC criteria") is a tool for assessing causality with respect to individual suspected adverse drug reactions. See WHO-UMC, The Use of the WHO-UMC System for Standardised Case Causality Assessment , at 1, https://www.who-umc.org/media/2768/standardised-case-causality-assessment.pdf (last visited Dec. 3, 2017) ("WHO-UMC Reference").
The Naranjo Scale is used in determining the causal link between a drug and an individual clinical event (i.e. , specific causation), which is what the Grall-Bronnec authors were assessing. As noted, the Naranjo Scale is not a general causation tool.
Again, the nine Bradford Hill factors are: (1) temporal relationship; (2) strength of the association; (3) dose-response relationship; (4) consistency or replication of the findings; (5) biological plausibility; (6) consideration of alternative explanations; (7) cessation of exposure; (8) specificity of the association; and (9) coherence with other knowledge. See Ref. Man. at 600.
Again, a dechallenge event occurs where a patient's adverse side effects partially or completely disappear once the drug is stopped. Rider ,
"Hollander Supp." refers to Dr. Eric Hollander's Rebuttal/Supplemental Report, DX-641.
"Luepker Rep." refers to Dr. Russell V. Luepker's Expert Report, ECF No. 462-1 at 2-15.
"Luepker Supp." refers to Dr. Russell V. Luepker's Rebuttal of Defendants' Expert Reports, ECF No. 426-5 at 2-10. "Luepker Dep." refers to the official transcript of Dr. Luepker's deposition testimony on June 16, 2017, ECF No. 462-1 at 97-181.
During his deposition, Dr. Luepker initially testified that he "certainly [has] some knowledge and understanding of dopamine and dopamine receptors because of an interest in that and some family health issues." See Luepker Dep., ECF No. 462-1 at 110. However, when questioned about the various aspects of Plaintiffs' proposed biological mechanism of action, he repeatedly stated that he "did not know" much about, and "would not hold [himself] up as an expert" on, virtually every issue. See
This is true except with respect to an analogy Dr. Luepker draws between Abilify's mechanism of action and that of dopamine replacement therapies used to treat Parkinson's Disease. See Luepker Rep., ECF No. 462-1 at 6, 16 (citing a peer-reviewed scientific article on impulse control disorders in Parkinson's patients taking dopamine replacement therapies). However, he never offers any evidence, or even an explanation, establishing the reliability of the analogy. See Rider ,
For example, Dr. Madigan served as an investigator for the FDA's Mini-Sentinel project, the goal of which was "to inform and facilitate development of a fully operational active surveillance system, the Sentinel System, for monitoring the safety of FDA-regulated medical products." See Madigan Rep., ECF No. 427-1 at 2. From 2009-2013, Dr. Madigan served as principal investigator for the OMOP, which studied the strengths and weaknesses of healthcare database research for identifying and evaluating safety and benefit issues of FDA-regulated drugs. See id. at 2-3. From 2010-2011, Dr. Madigan was a member of a subcommittee of the FDA Science Board charged with reviewing the Center for Drug Evaluation and Research's pharmacovigilance program. See id. at 3. From 2011-2014, Dr. Madigan was a member of the FDA's Drug Safety and Risk Management Advisory Committee, which advises the FDA Commissioner of risk management, risk communication, and quantitative evaluation of adverse events reports for FDA-regulated medical products. See id. at 3.
See, e.g., Rheinfrank ,
Dr. Madigan analyzed the same 10 other atypical antipsychotics that the FDA analyzed as part of its 2016 Pharmacovigilance Review, which were: olanzapine, quetiapine, risperidone, asenapine, brexpiprazole, clozapine, iloperidone, lurasidone, paliperidone, and ziprasidone. See Madigan Rep., ECF No. 427-1 at 16; FDA Pharm. Vigil., ECF No. 428-11 at 27.
Those four dates were: (1) [* * * REDACTED * * *] ; (2) Quarter 4, 2015-prior to first lawsuits being filed in early 2016; (3) Quarter 2, 2016-prior to warning added in August 2016; and (4) the most recent FAERS data available as of the date of Dr. Madigan's analysis. See Madigan Rep., ECF No. 427-1 at 17.
Dr. Madigan measured disproportionality in adverse event reporting by calculating an EB05 score for each drug as of each date. Again, the EB05 is a statistic used by the FDA to estimate the strength of an observed association between a drug and reports of a particular adverse effect. See Section II(C). All of Abilify's EB05 scores, as calculated by Dr. Madigan, were greater than 2.0, which is the "widely accepted threshold" indicator of a statistically significant association between adverse event reports and a drug, signaling potential safety issues that require further investigation. See Madigan Tr., 596-4 at 20.
More specifically, the EB05 score for Abilify in the unrestricted analyses as of the four different dates was: (1) Quarter 3, 2014-2.90; (2) Quarter 4, 2015-13.16; (3) Quarter 2, 2016-18.55; and (4) Quarter 3, 2016-20.79. See Madigan Rep., ECF No. 427-1 at 17. The EBO5 score for Abilify in the analyses restricted to bipolar and schizophrenia patients was: (1) Quarter 3, 2014-2.41; (2) Quarter 4, 2015-3.10; (3) Quarter 2, 2016-3.55; and (4) Quarter 3, 2016-3.90. See id. at 18.
"Power" is a statistical concept that quantifies the ability of a study to detect an association that truly exists. See ASARCO, Inc. v. Occupational Safety and Health Admin. ,
By Dr. Madigan's calculations, the clinical trials, given their small size, had a 6% probability or chance of detecting a 25% increased risk of pathological gambling with Abilify, a 9% chance of detecting a 50% increased risk, a 14% chance of detecting a 75% increased risk, and a 22% chance of detecting a 100% increased risk. See Madigan Rep., ECF No. 427-1 at 25-26.
Dr. Madigan calculated [* * * REDACTED * * *] . By Dr. Madigan's calculation, [* * * REDACTED * * *] .
Again, a relative risk of 1.0 means there is no difference in risk between the exposed, comparator, and placebo groups; in other words, there is no association between exposure to the drug and the adverse effect. See Ref. Man. at 567; see also Allison ,
As discussed in Section II(C), the p -value is an indicator of statistical significance, which, in this context, provides an estimate of the probability that chance alone produced the association between Abilify, hypersexuality, impulsive behavior, and increased libido. Generally, p -values are considered "statistically significant" where they are less than or equal to 5% (p = 0.05). See Ref. Man. at 251; see also Eastland v. Tenn. Valley Auth. ,
Dr. Madigan testified that [* * * REDACTED * * *] .
The Court separately analyzed the reliability of Dr. Madigan's opinions regarding the Etminan Study in Section II(C).
To the extent this objection is directed, more broadly, at Dr. Madigan's opinion on general causation, the objection is denied as moot because Dr. Madigan's general causation opinion has been excluded.
"Madigan Supp." refers to Dr. David Madigan's Rebuttal Report, ECF No. 427-1 at 79-92.
See Kuhn ,
[* * * REDACTED * * *] . See Madigan Rep., ECF No. 427-1 at 29.
See also Joiner ,
The Court notes that Defendants have not objected to Dr. Madigan's reliance on the one statistically significant p -value (.03) he calculated from the clinical trials, based on the 6.16-fold increase in the risk of impulsive behavior with Abilify relative to comparator drugs. This p -value is reliable and admissible.
With two exceptions, Plaintiffs' criticisms of Dr. Weed affect only the weight to be afforded his opinion, not its admissibility. First, Dr. Weed will not be permitted to testify that the Bradford Hill factor of consistency can only be satisfied by the existence of multiple epidemiological studies, see Weed Rep., ECF No. 419-3 at 45, because this opinion is not supported by the scientific literature. See, e.g. , Ref. Man. at 604; Bradford Hill Article, ECF No. 460-4. Second, Dr. Weed will not be permitted to represent the AMSTAR criteria as the "minimum requirements for a scientifically rigorous systematic review," such as the literature reviews performed by Plaintiffs' experts. See id. at 33. The record reflects that the developers of AMSTAR recommend "further testing" of their system before "strong recommendations can be made on its use." See Shea, et al., Development of AMSTAR: A Measurement Tool to Assess the Methodological Quality of Systematic Reviews , 7 BMC Med. Research Methodology 10 (2007), ECF No. 419-35 at 4,7.
The Court finds Dr. Blier's opinion reliable except with respect to his opinion as to the high concentrations of D1and D2receptors in the nucleus accumbens, which the Court has already excluded as inconsistent with the record. See Section II(C)(4)(a).
"Leiderman Rep." refers to Dr. Deborah B. Leiderman's Expert Report, ECF No. 420-3.
"Leiderman Dep." refers to the official transcript of Dr. Deborah B. Leiderman's deposition testimony on June 21, 2017, ECF No. 456-2.
Although Plaintiffs argue that Dr. Leiderman failed to properly explain how her experience led her to the conclusions she reached in this case, they have not specifically argued that Dr. Leiderman is not qualified to opine on matters pertaining to FDA regulations.
Dr. Leiderman testified that she is not a causation expert and has not offered a general causation opinion that Abilify can cause pathological gambling or other impulse control disorders. See Leiderman Dep., ECF No. 456-2 at 19-20. She stated that her opinion only "address[ed] FDA's interpretations of the data and their findings of an association and not causality." See id. Dr. Leiderman's position is that the "FDA has not found evidence and data to be sufficient to reach" a finding of causation and that "that's what [her opinion is] describing." See id.
See, e.g. , Glenmullen Rep., ECF No. 424-1 at 132; Hollander Rep., ECF No. 459-1 at 36; Luepker Rep., ECF No. 462-1 at 7.
See, e.g., Jones v. Novartis Pharmaceuticals Corp. ,
"Winstanley Rep." refers to Dr. Catharine A. Winstanley's Expert Report, ECF No. 461-1.
"Winstanley Tr." refers to the official transcript of Dr. Catharine A. Winstanley's testimony at the Daubert hearing, ECF No. 596-8 at 93-11.
According to Dr. Winstanley, the three components of a translationally valid animal model are: (1) face validity, which refers to how much the behavioral task designed for use in rodents resembles, on its face, a behavioral task that a human subject might perform; (2) construct validity, which refers to whether the same brain regions and neurotransmitters that regulate a particular behavior in humans regulate that same behavior in rodents; and (3) predictive validity, which refers to whether rodent models of a particular behavioral task have been shown to accurately predict human performance on the same task. See Winstanley Rep., ECF No. 461-1 at 7-8; Winstanley Tr., ECF No. 596-8 at 96-97.
See, e.g. , P. Cocker et al., Chronic Administration of the Dopamine D2/3 Agonist Ropinirole Invigorates Performance of a Rodent Slot Machine Task, Potentially Indicative of Less Distractible or Compulsive-Like Gambling Behavior , 234 Psychopharmacology 137 (2017) (ropinirole ); Rokosik & Napier, Pramipexole-Induced Probabilistic Discounting: Comparison Between a Rodent Model of Parkinson's Disease and Controls , 37 Neuropsychopharmacology 1397 (2012) (pramipexole ); L. Cervo et al., Selective Antagonism at Dopamine D3 Receptors Attenuates Cocaine-Seeking Behaviour in the Rat , 10 Int'l J. Neuropsychopharmacology (2007) (a D3receptor antagonist); P. Flores & R. Pellón, Antipunishment Effects of Diazepam on Two Levels of Suppression of Schedule-Induced Drinking in Rats , 67 Pharmacology , Biochemistry & Behavior 207 (2000) (diazepam ).
For frame of reference, Plaintiffs' expert, Dr. Bechara, spent over two hours on the witness stand. See Bechara Tr., ECF No. 596-3.
For the Court's discussion of the distinction between an association and causation, see Section II(B)(1)(a).