California Court Excludes Plaintiff Expert for Abusing Common Bradford Hill Analysis

A California appellate court has affirmed the exclusion of an expert witness who “(1) unreliably found causation based on [a single] study alone while disregarding other human data …; (2) analyzed animal data even though he was unqualified to do so; and (3) misapplied [several] of the nine factors of the Bradford Hill analysis.” Onglyza Product Cases involved claimed negative cardiovascular effects from a diabetes medication. The rulings are, however, broadly applicable to expert witnesses generally and to the recurring minefield that is Bradford Hill.

“A trial court does not abuse its discretion in excluding expert testimony on general causation when the expert’s opinion is based on a single study that provides no reasonable basis for the opinion offered.” Here, the studies’ authors said more study was needed to address causation.

“We do not hold that one randomized controlled trial is never sufficient to establish general causation, but on this record, the trial court did not abuse its discretion in finding that Dr. Goyal’s reliance on SAVOR alone to establish general causation was logically unsound, especially given Dr. Goyal’s own agreement that SAVOR’s finding needed to be replicated in order to determine causation.”

The trial court’s “decision was based on various methodological defects it found in Dr. Goyal’s application of six of the nine Bradford Hill factors, and that because he failed to weigh them together, it could not identify any predicate opinion on a specific factor that was not essential to his ultimate opinion. As a result, it concluded that methodological defects in any of the factors would upset the ultimate opinion on causation. This was a proper exercise of the court’s gatekeeping responsibility.”

In some instances, the court ruled that the expert was “refusing to engage with a factor of the Bradford Hill analysis on its terms” by essentially re-defining the terms to suit his opinions. Sound familiar?

For example, “consistency … is upheld when the same finding is shown in multiple studies across different populations and settings.” Yet the expert relied on only one study. He also relied on data from preclinical animal studies, though he was not qualified to interpret animal data.  

Similarly, “specificity” is met “if the exposure is associated only with a single disease or type of disease.” The expert testified that specificity was nonetheless met through the single study because “the randomized controlled trial allows you to fulfill that criterion.” “[A]nother example of Dr. Goyal refusing to engage with a factor of the Bradford Hill analysis on its terms.” 

“‘Biological plausibility’ refers to whether there is a plausible biological mechanism to explain a cause-and-effect relationship between exposure and disease. … The trial court noted that the strongest mechanism Dr. Goyal could identify was only ‘a proposed hypothesis.’” His opinion was therefore rejected because he did “not undertake an analysis of whether the data that exists supports or undermines his opinion that the proposed mechanisms are plausible.”

“‘Analogy’ considers whether there have been associations found between a related or similar substance to the one at issue and the disease or outcome.” The expert analogized to a different class of diabetes medication than the one at issue (DPP-4). “The trial court reasonably concluded that this opinion was not reliable because the only reason for Dr. Goyal to analogize saxagliptin to TZDs rather than to other DPP-4 inhibitors was that the former supported his ultimate conclusion on causation and the latter did not.”

Bonus for the defense: because general causation must be proven by expert evidence, and plaintiffs’ sole expert on general causation was excluded, summary judgment followed. The trial court denied plaintiffs’ request to re-open discovery and allow them to find another expert. The Court of Appeal affirmed that too.

New York Appellate Courts Clarify Defense-Friendly Standards on Causation

Recently, New York’s highest court and the intermediary appellate court (Appellate Division: First Department) that hears all appeals arising from New York City’s Asbestos Litigation (“NYCAL”) have ruled that it is a plaintiff’s burden to present evidence of (1) what base line exposure is necessary to cause disease; and (2) that the exposure experienced from each product reached, or exceeded, that level sufficient to cause the disease. Furthermore, common assertions by plaintiff experts like “no safe dose” and “all asbestos is dangerous” were ruled not sufficient to meet this burden.

These were set out in decision of New York’s highest court, the Court of Appeals, in Nemeth, which set aside a jury verdict (and in which our firm submitted an amicus brief).

Although we have recognized that in any given case it may be “difficult, if not impossible, to quantify a plaintiff’s past exposure” to a toxin (Sean R., 26 NY3d at 812), our standard itself is not “impossible” for plaintiffs to meet (dissenting op at 25). We must, as always, strike a balance between the need to exclude “unreliable or speculative information” as to causation with our obligation to ensure that we have not set “an insurmountable standard that would effectively deprive toxic tort plaintiffs of their day in court” (Parker, 7 NY3d at 447). The requirement that plaintiff establish, using expert testimony based on generally accepted methodologies, sufficient exposure to a toxin to cause the claimed illness strikes the appropriate balance (see Cornell, 22 NY3d at 784). The fault here is not in our standard, but in plaintiff’s proof.

Nemeth v. Brenntag N. Am., No. 24, 2022 WL 1217464, at *1 (N.Y. Apr. 26, 2022)

In Olsen, the First Department set aside one of the most massive NYCAL jury awards to date: after remittitur, $15 million in compensatory damages and $105 million in punitive damages. The First Department held that plaintiffs failed, as a matter of law, to carry their burden to establish sufficient exposure to defendant’s talc product to cause plaintiff’s mesothelioma.

Even if it is assumed that plaintiffs presented sufficient evidence to support their mineral expert’s estimate of the amount of asbestos to which plaintiff Donna Olson was exposed each time she used J & J’s talcum powder products, plaintiffs’ medical expert never set forth a scientific expression of the minimum lifetime exposure to asbestos that would have been sufficient to cause mesothelioma, the disease in question.

Matter of New York City Asbestos Litig.(Olsen), No. 14875, 2022 WL 2812015, at *1 (1st Dept. 2022).

Olsen was the first NYCAL verdict overturned on appeal following Nemeth. However, the First Department did not stop there. It issued three more decisions clarifying and extending Nemeth to motions for summary judgment—contrary to the plaintiffs’ argument throughout New York that Nemeth applied only to post-verdict rulings.

All three cases involved claimants diagnosed with lung cancer who alleged asbestos exposure from Amtico floor tiles. The court confronted the same argument and experts on causation in each case.

In reversing the lower court’s denial of defendant’s motions for summary judgment, the First Department held that defendant made out a prima facie case that plaintiffs were not exposed to sufficient quantities of respirable asbestos from defendant’s product to cause their disease, based on a 2007 simulation study showing that cutting, scoring and disruption of its floor tile did not produce sufficient airborne asbestos above ambient levels to cause the disease.

The court held that plaintiffs failed to raise an issue of fact by failing to provide any quantification and merely arguing “no safe” levels:

Dr. Ginsburg generally concludes that “[t]here is no safe minimum level of exposure to asbestos with respect to lung cancer” and that “manipulation of asbestos containing floor tiles can result in release of asbestos fibers into the workers’ environment that are exponentially greater than the ambient level of exposure.” He also states that the asbestos process releases “visible dust” and that such dust is “certainly in dangerous concentration.” However, Nemeth holds that such broad pronouncements and conclusions will not satisfy a plaintiff’s causation burden, which is to show the levels of asbestos that the plaintiff was exposed to and that the levels are known to cause lung cancer. Likewise, to the extent Dr. Ginsberg’s [sic] conclusions are based upon the presence of visible dust emanating from an asbestos-containing product, this theory fails to satisfy a plaintiff’s burden on causation in asbestos cases. Id.

Dyer v. Amchem Prod. Inc., No. 13739, 2022 WL 2811995, at *1 (1st Dept. 2022).

The court rejected plaintiffs’ argument that defense-funded experiments invalidates their conclusions, particularly given that “[p]laintiff offered no expert to counter ABI’s calculation of decedent’s cumulative lifetime exposure, and thus no question of fact was raised as to its validity.” Killian v. A.C. & S., Inc., (Grunert), No. 114345/02, 2022 WL 2812016, at *1 (1st Dept. 2022). Although Dr. Ginsberg pointed to simulation studies measuring an average level of airborne asbestos as high as 0.27 f/cc from floor tile work, the court held that he did not provide any correlation between the asbestos fiber levels to which plaintiff may have been exposed and the amount of inhaled asbestos that would have caused decedent’s lung cancer. Pomponi v. A.O. Smith Water Prod. Co., No. 14982, 2022 WL 2811997, at *1 (1st Dept. 2022).

In each of these four cases, the First Department made clear that a plaintiff cannot establish his or her burden at trial or summary judgment (after defendant meets its initial prima facie burden), by relying on the generalized expert opinions that exposure to a toxin is “excessive” or “far more” than others and, therefore, sufficient to cause a disease. The court needs to be presented with actual quantification of the level of asbestos exposure need to cause the disease at issue and that plaintiff’s inhalation of asbestos from defendant’s product met or surpassed that level.

California appellate court bucks national trend, allows plaintiff experts to opine that “every asbestos exposure is a substantial factor”

Courts from around the country have rejected efforts by plaintiff experts to testify that every asbestos exposure is a substantial factor in causing disease. On March 3, 2016, California’s second appellate district went the other way, and held in Davis v. Honeywell International, Inc. that the controversial “every exposure counts” theory is admissible under governing expert witness law.   Thus, although trial courts are supposed to play a “gatekeeper” role in keeping out unreliable expert evidence (Sargon Enterprises, Inc. v. University of Southern California (2012) 55 Cal.4th 747), Davis breaks the gate wide open in allowing a jury, not the trial court in its “gatekeeper” role, to decide whether to accept the theory.

Davis was aGATEPICTURE wrongful death case.  Sam Davis  worked as an auto mechanic and home remodeler from approximately 1963 to 1979.  He performed “one or two” brake jobs per day, and always used Bendix brake linings (for which defendant Honeywell was responsible). These linings contained 50 percent chrysotile asbestos by weight.  He was also allegedly exposed to asbestos as a result of his home remodel work.

Prior to trial, Honeywell filed a motion in limine to preclude plaintiff from presenting expert opinion testimony that every exposure to asbestos above background contributed to decedent’s disease. The motion was denied, and plaintiff’s pathologist (James A. Strauchen, M.D.) and pulmonologist (William Rom, M.D.) were permitted to testify and advance the theory. Ultimately, the jury found for plaintiffs, and Honeywell appealed.

Honeywell’s primary basis for appeal was that the “every exposure counts” testimony of Dr. Strauchen should have been excluded. Honeywell advanced four arguments:  (1) the testimony was speculative and illogical; (2) the regulatory standards Strauchen relied upon cannot establish causation; (3) no appropriate scientific literature supports the theory; and (4) the theory is contrary to California causation law espoused in Rutherford v. Owens Illinois (1997) 16 Cal.4th 953, which held that not every exposure to asbestos is a “substantial factor” in causing disease.

Davis rejected each of Honeywell’s arguments. “Having reviewed much of the commentary and scientific literature cited in support of and against the ‘every exposure’ theory, we conclude that the theory is the subject of legitimate scientific debate.   Because in ruling on the admissibility of expert testimony the trial court ‘does not resolve scientific controversies (Sargon), it is for the jury to resolve the conflict between the every exposure theory and any competing expert opinions.”  The court focused largely on the mere existence of evidence that supported the “every exposure counts” theory, and declined to weigh the evidence or any competing inferences.   “While Honeywell is generally correct that in many (or even most) instances epidemiological studies provide the best evidence of causation, its implied argument that it is improper for an expert to rely upon any other tools to determine causation, such as case reports, is not universally accepted.”  As to Honeywell’s argument that “every exposure” contravenes Rutherford, Davis  interpreted Rutherford as not requiring a “dose level estimation,” instead issuing a sweeping statement interpreting Rutherford as supporting the conclusion that even a very small “dose” could increase the risk of asbestos-related cancer.  Davis distinguished the many cases from other jurisdictions rejecting this argument, including Betz v. Pneumo Abex, LLC (2012) 615 Pa. 504, Bostic v. Georgia-Pacific Corp. (Tex. 2014) 439 S.W.3d 332 and Moeller v. Garlock Sealing Technologies, LLC (6th Cir. 2011) 660 F.3d 950. “[W]e simply disagree” that the “every exposure” theory could not be “reconciled with the fact that mesothelioma and other asbestos-related diseases are dose-dependent.”

The Davis court did state, however, that “[w]e caution that our discussion of the materials Dr. Strauchen relied upon should not be seen as approval of either side in that scientific dispute.  Rather, we rely upon the rule of Sargon that although trial courts ‘have a substantial ‘gatekeeping’ responsibility,’ in evaluating proposed expert opinion . . . the gate tended is not a partisan checkpoint . . . If the opinion is based on materials on which the expert may reasonably rely in forming the opinion, and flows in a reasoned chain of logic from those materials rather than from speculation or conjecture, the opinion may pass, even though the trial court or other experts disagree with its conclusion or the methods and materials used to reach it.  (emphasis added)

Further, although much of the discussion relates to the “any exposure” theory, Davis pointed out that the case did not hinge on that theory.  “In this case, Dr. Strauchen was presented with a hypothetical based on the facts surrounding Davis’ exposure to dust from his work on Bendix brake linings, and testified as to estimates of the amount of asbestos fibers contained in visible dust. Therefore, his conclusion that Davis’ exposure to Bendix brake linings was a substantial factor in contributing to the risk of mesothelioma was not based simply on “any exposure” to asbestos, but instead related to an estimate of actual exposure.”

The decision is not yet final. It is still subject to a petition for rehearing, which could result in a change in the opinion, and to either or both a request for depublication and a petition for review to the California Supreme Court, either of which if granted would make this decision uncitable in California courts, though not necessarily elsewhere.

“Dream Scenario” For Defense with Bad Science Behind Herbal DNA Testing

Gordon & Rees partner James Scadden was interviewed and quoted in a recent article on titled “‘Dream Scenario:’ Herbal Supplements Sitting Pretty After AG’s Blunder.”

The article discusses major flaws in a report by the New York State Attorney General’s office condemning the supplements industry – particularly products sold by GNC – as not containing the herbal substances as labeled. Following the report, GNC’s stock declined 5% following the cease-and-desist letter that was sent to GNC as well as other retailers including Target, Walgreens, and Walmart. That action was based on DNA test findings that only 21% of samples actually contained the plants or herbs advertised. Members of the plaintiffs’ bar have initiated lawsuits based upon the alleged mislabeling.

However, it has since become apparent that the research methods used in the study were both unreliable and misleading. In the process of making supplements, DNA is necessarily eliminated or denatured during the extraction and purification process. Had significant DNA indicators been found, it would have meant the products were poorly made. Thus, the New York AG got it backwards, and wrong, i loved this article since it helped me understand what supplements you actually need.


The AG’s misguided report came under fire from third-party experts who are critics of the supplement industry. While they lobby for the public to be better informed as to the possible hazards of herbal supplements, they recognize that unsupportable investigations are a disservice to that purpose.

In commenting on the story, Scadden said, “The fact that third-party experts typically critical of the industry have now challenged the methodology used by the New York State Attorney General is a dream scenario for any attorney representing a company responding to a lawsuit. The common attack on expert defense testimony is to question the impartiality of the expert and to assert that the expert is somehow beholden to the defendant that hired them. But when those same experts have acted in the past as critics of companies in the same industry, it allows for unassailable arguments about that expert’s impartiality and credibility. Lawyers defending companies in the supplement industry will now happily point to the work of past critics of the industry to defend cases,” he concluded. The complete article can be read by clicking here.

Surprisingly, several days thereafter the New York AG called a press conference to announce a settlement with GNC whereby GNC agreed to certain DNA testing of their products. The testing will be performed under a different protocol than that used by the AG so as to provide results that actually provide relevant information regarding the source materials for the supplements. GNC also agreed to broad testing for contaminants, basically allegans, agreed to post information on their website and to place informational signs in their stores, and finally to provide annual reports to the New York AG regarding their DNA testing of their products.

There may be some expectations that other suppliers will act in a similar fashion, but it must be remembered that such conduct is not required by law and that the Congress after due deliberation has implemented its own scheme that was felt to be appropriate There is also the danger that when you attempt to accomplish what are felt to be remedial efforts by a piecemeal approach through multiple cases or various jurisdictions, you can end up with inconsistent, poorly reasoned results.

It is unlikely that what GNC has done will become an industry standard because it does not have the force of law, and the industry itself and its products are so diverse that there is no “one size fits all” response to the concerns described by the AG. Further, in some jurisdictions, doing what GNC has committed to do may actually leave a supplier in technical noncompliance with other state laws. For example, in California there is a separate regulatory regime which requires labeling in certain circumstances. The labeling in California is dictated by regulations and would arguably not be consistent with what GNC has agreed to in New York.

The recent activity of the NY AG and the response by GNC will certainly generate extensive discussion in the industry, though it is yet to be seen what changes may result.

Plaintiffs’ Experts’ “Cherry-Picking” of Scientific Studies Not Permitted

On February 20, 2015, New Jersey Superior Court Judge Nelson C. Johnson issued a decision in the New Jersey Accutane Multicounty Litigation that, if not reversed on appeal, will likely result in the dismissal of several thousand cases pending against Hoffmann-LaRoche. The court granted the pharmaceutical company’s motion to bar plaintiffs’ experts’ testimony regarding Accutane, and its alleged propensity to cause Irritable Bowl Disease (“IBD”), including Crohn’s Disease (“CD”). The court made its determination after conducting an exhaustive analysis of the scientific literature and the testimony of both sides’ experts. The decision is noteworthy for the court’s painstaking assessment of the body of scientific literature on medical causation. Defendant’s counsel clearly did a superb job in educating Judge Johnson on the science.

ETT BLOG_cherriesAccutane was approved by the Food and Drug Administration in 1982 to treat a severe form of acne, which can cause disfigurement on the face and back of those affected. Crohn’s Disease is a serious chronic inflammation of the gastrointestinal tract that can cause gastrointestinal bleeding, among other symptoms, and carries an increased risk of cancer. Most scientific literature has concluded that the cause of CD and IBD remains unknown.

To establish a causal connection between Accutane and IBD and CD, plaintiffs presented the court with two expert witnesses, Arthur A. Kornbluth, M.D., and David Madigan, Ph. D, both of whom are accomplished leaders in their professions, with highly impressive credentials. Dr. Kornbluth is a Clinical Professor of Medicine at the Icahn School of Medicine at Mount Sinai University. He specializes in gastroenterology and has published over one hundred peer-reviewed articles, abstracts and textbook chapters. Dr. Madigan is a Professor of Statistics at Columbia University and Executive Vice President of Arts & Sciences and Dean of Faculty. He has published over one hundred-fifty technical papers and served as an investigator for monitoring the safety of FDA-regulated medical products.

To rebut the plaintiffs’ experts, defendants relied upon the testimony of two experts, Steven N. Goodman, M.D., M.H.S. Ph. D, and Maria Oliva-Hempker, M.D, who are also exceptionally learned and accomplished professionals. Dr. Goodman practices in the field of epidemiology. He is a Professor and Associate Dean for Clinical Research at Stanford University and has received numerous awards in his area of expertise. Dr. Oliva-Hempker is a Professor of IBD and Chief of Division of Pediatric Gastroenterology & Nutrition at the Johns Hopkins University School of Medicine. She has been published in over seventy treatises and medical texts and maintains a substantial presence in educating the public on IBD. Thus, from the standpoint of professional credentials, the two sides were well-represented and seemingly evenly matched.

Of particular significance to the court in making its analysis was The Reference Manual on Scientific Evidence (3d Ed.), issued by the Federal Judicial CenterThe state court looked to the Reference Manual for guidance on the reasonableness standards of the scientific community and its evaluation of the epidemiological studies. The use of federal guidance by a New Jersey state court is noteworthy.

In determining that plaintiffs’ experts’ was unreliable Judge Johnson criticized plaintiffs’ experts for “cherry-picking the evidence.”  “The examination of the ‘lines of evidence’ by Plaintiffs’ experts was highly selective, looking no further than they wanted to — cherry-picking the evidence — in order to find support for their conclusion-driven testimony in support of a hypothesis made of disparate pieces, all at the bottom of the medical evidence history.”

The court also caught Dr. Kornbluth taking a position in a published article that was the opposite of what he argued in court. During the pre-publication peer review process, Dr. Kornbluth refused to associate Isotretinoin as a cause of IBD, although in court he had no reservations arguing that Isotretinoin caused IBD. In order to define the prodromal period of CD, plaintiffs’ relied on a single study with only 76 subjects and ignored studies with much larger patient groups. The court found that, “the unsound nature of plaintiffs’ methodology in relying upon such a study becomes readily apparent when compared with the population studies, involving hundreds of thousands of subjects presented to the court. Plaintiffs’ rationalization for ignoring the other studies is assertedly their failure to account for a lengthy prodrome of CD. Yet here again, plaintiffs’ experts engage in their finely-tuned selectivity of the evidence by disregarding eight of nine prodromal studies.” The court found further that plaintiffs’ experts demonstrated the talent of “the self-validating expert, who uses scientific terminology to present unsubstantiated personal beliefs.”

In one instance, plaintiffs’ experts interpreted the results of a study they relied on contrary to the authors’ own stated conclusions. The study’s authors concluded that the risk for IBD following Isotretinoin exposure had no statistical significance, but the experts argued to the contrary. The court commented, “It is one thing to stand alone in the world of science, advancing a hypothesis that others do not accept. It is quite another thing to advance a hypothesis that can only be supported by disregarding valid scientific research.” Even more ineffective was the plaintiffs’ reliance on a second study with a particularly small patient population to define the prodromal period of CD. The court asked rhetorically, “with regard to these two studies, one wonders whether Dr. Kornbluth or Dr. Medigan would cite them as meaningful any place but a courtroom.”  The court found it unlikely that Dr. Kornbluth or Dr. Medigan, who took such pride in their professional accomplishments, would rely on these studies as defining treatises. Excoriating plaintiffs’ counsel and their experts, the court stated that, “the reliance upon these two studies is fatal and reveals the lengths to which legal counsel and their experts are willing to contort the facts and torture the logic associated with plaintiffs’ hypothesis.”

Several observations that may be of use in other cases.

Adverse Event Reports. It is noteworthy that the court did not credit plaintiffs’ reliance on Adverse Event Reports.  Plaintiffs frequently made reference to these anecdotal reports filed with the FDA. But the FDA itself notes that there is no certainty that the reported circumstance are actually attributable to the drug the patient was taking. Causal assessments are difficult to make because these reports are, according to a scholarly text cited by the court, “usually based on suspicion, and may be preliminary, ambiguous, doubtful or wrong.” Moreover, there is concern of potential abuse of these reports, especially by attorneys. “The legal profession is a bulwark of our society, yet the courts should never underestimate the resourcefulness of some attorneys.” Out of 2,214 cases of IBD resulting from Isotretinoin, attorneys reported 87.8% cases, as compared to 6% by physicians and 5.1% by consumers.

Animal Studies. The court also criticized plaintiffs’ reliance on animal studies. Again, referencing the Reference Manual, the court concluded that animal studies have two major disadvantages. The first is the obvious variation in responses among different species of animals. “The second difficulty with inferring human causation from animal studies is that the high dose customarily used in animal studies requires consideration of the dose-response relationship and whether a threshold no-effect does exist.” The problem with the dog study in this case was that even though dogs are mammals, the dogs in the experiment were euthanized after testing, so there was no evidence of whether the dogs’ intestines suffered any permanent harm. Equally important, dogs do not suffer from IBD.

The Reference Manual on Scientific Evidence (3d. Ed.) should never be overlooked by the practitioner preparing a Daubert motion. As evidenced by this case, the Reference Manual has persuasive power in both state and federal courts.

It is defense counsel’s job to teach the science to the presiding judge. Considering the case load of most judges, this is not an easy task. In this case, Hoffmann-LaRoche was fortunate to have a judge willing to make this herculean effort.

Image courtesy of Flickr by Audrey

Challenging Causation in Toxic Tort Cases: The Dose-Response Theory – A Threshold Issue

The dose-response theory requires a toxic tort plaintiff to establish “scientific knowledge of the harmful level of exposure to a chemical plus knowledge that the plaintiff was exposed to such quantities” to meet his or her threshold burden of proof.  McClain v. Metabolife Int’l, Inc., 401 F.3d 1233, 1241 (11th Cir. 2005) (citing Allen v. Pennsylvania Eng’g Corp., 102 F.3d 194, 199 (5th Cir. 1996).  See also Mitchell v. Gencorp, 165 F.3d 778, 781 (10th Cir. 1999) (quoting Wright v. Willamette Indus., Inc., 91 F.3d 1105, 1106 (8th Cir. 1996)).  If a plaintiff does not present expert testimony sufficient to sustain this burden, the plaintiff’s case is vulnerable to attack via a motion in limine, motion for summary adjudication or even an appeal from an adverse verdict.  Accordingly, defense counsel should assess, as early as possible, the suitability of expert testimony offered to support the plaintiff’s case.

On a basic level, the dose-response relationship is “[a] relationship in which a change in amount, intensity, or duration of exposure to an agent is associated with a change – either an increase or decrease – in risk of disease.”  McClain, 401 F.3d at 1241-1242.  Any expert “who avoids or neglects this principle of toxic torts without justification casts suspicion on the reliability of his methodology.”  Id., 401 F.3d at 1242.  Accordingly, that expert’s methodology is susceptible to a Daubert challenge.  See Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 125 L. Ed. 2d 469, 113 S. Ct. 2786 (1993).

For instance, in McClain, the U.S. Court of Appeals for the Eleventh Circuit reversed a jury verdict in a products liability action against Metabolife International, Inc. where it found that the trial court erroneously admitted expert testimony purporting to establish causation between the herbal weight-loss supplement at issue and the plaintiffs’ medical conditions.  McClain, 401 F.3d at 1236.  While the plaintiffs offered testimony regarding the amount of the supplement ingested, their expert could not provide any opinions about “the general dose-response levels for Metabolife’s toxicity, i.e., the dose or level of exposure at which it causes harm.”  McClain, 401 F.3d at 1241.  Even though an expert need not provide precise numbers to substantiate the dose-response relationship, “the link between an expert’s opinions and the dose-response relationship is a key element of reliability in toxic tort cases.”  Id., 401 F.3d at 1241, Fn. 6.

The court’s analysis in McClain figures prominently in a recent products liability case in the Eleventh Circuit decided on September 11, 2014.  In Chapman v. The Procter & Gamble Distributing, LLC, 766 F.3d 1296 (11th Cir. 2014), the plaintiffs brought claims against several Procter & Gamble entities alleging that an ingredient in Fixodent, a denture adhesive, caused one of the plaintiffs to suffer from myelopathy, a neurological condition or spinal-cord disorder that affects the upper and lower extremities.  The plaintiffs’ claims did not survive summary judgment at the trial court level and the Eleventh Circuit affirmed that ruling on appeal.  Id.  The Chapman court discussed the importance of the dose-response theory as follows:

Recognizing all substances potentially can be toxic, the [trial] judge noted “ ‘the relationship between dose and effect (dose-response relationship) is the hallmark of basic toxicology,’ ” and “ ‘is the single most important factor to consider in evaluating whether an alleged exposure caused a specific adverse effect.’ ” In re Denture Cream Prods. Liab. Litig., 795 F. Supp. 2d at 1351-52 (quoting McClain, 401 F.3d at 1242). The judge noted, however, neither the Chapmans’ general-causation experts “nor the articles on which they rely determine how much Fixodent must be used for how long to increase the risk of a copper-deficiency, or for how long a copper-deficiency must persist before an individual is at an increased risk of developing a myelopathy.” Id. at 1352.

Without critical evidence regarding reliable methodologies for establishing causation, the plaintiffs’ claims were doomed.  Chapman, 766 F.3d 1296.

The McClain analysis of the dose-response theory is influential in the Eleventh Circuit and beyond, having also been cited by U.S. District Courts in the Second, Third, Sixth, Eighth, Ninth, and D.C. Circuits and the Federal Claims Court.  See Second Circuit – Deutsch v. Novartis Pharms. Corp., 768 F. Supp. 2d 420 (E.D.N.Y. 2011), Colon v. Abbott Labs., 397 F. Supp. 2d 405; Third Circuit – Patrick v. FirstEnergy Generation Corp., 2014 U.S. Dist. LEXIS 43036 (W.D. Pa. Mar. 31, 2014); Sixth Circuit – Rose v. Matrixx Initiatives, Inc., 2008 U.S. Dist. LEXIS 110116 (W.D. Tenn. Dec. 9, 2008), Adams v. Cooper Indus., 2007 U.S. Dist. LEXIS 55131 (E.D. Ky. July 30, 2007); Eighth Circuit – Beylin v. Wyeth (In re Prempro Prods. Liab. Litig.), 738 F. Supp. 2d 887, CCH Prod. Liab. Rep. P18490 (E.D. Ark. 2010), In re Baycol Prods. Litig., 532 F. Supp. 2d 1029 (D. Minn. 2007); Ninth Circuit – Monroe v. Zimmer US Inc., 766 F. Supp. 2d 1012 (E.D. Cal. 2011), Henricksen v. ConocoPhillips Co., 605 F. Supp. 2d 1142, 78 Fed. R. Evid. Serv. (CBC) 857 (E.D. Wash. 2009), Lusch v. Matrixx Initiatives, Inc., 2007 U.S. Dist. LEXIS 72068, 74 Fed. R. Evid. Serv. (CBC) 880 (D. Or. Sept. 25, 2007), O’Hanlon v. Matrixx Initiatives, 2007 U.S. Dist. LEXIS 65655 (C.D. Cal. Jan. 3, 2007); D.C. Circuit – Arias v. DynCorp, 928 F. Supp. 2d 10 (D.D.C. 2013); Federal Claims Court – Graves v. Sec’y of HHS, 2010 U.S. Claims LEXIS 1037 (Fed. Cl. Sept. 21, 2010).  But see In re Zicam Cold Remedy Mktg., Sales Practices & Prods. Liab. Litig., 2011 U.S. Dist. LEXIS 79244 (D. Ariz. July 15, 2011) (criticizing the McClain court’s application of the “toxic dose” requirement in environmental exposure litigation in the context of a drug products liability action).

Challenging the reliability of an expert’s methodology where the dose-response relationship has been neglected can streamline the issues at trial in a toxic tort case and, in some instances, may obviate the need for trial.  Accordingly, an examination of the dose-response theory should be an early and recurring priority.