Barrera v. Monsanto Company ( 2019 )

IN THE SUPERIOR COURT OF THE STATE OF DELAWARE
JOSELIN BARRERA, et al.,
Plaintiffs,
V. C.A. No. N15C-10-118 VLM
MONSANTO COMPANY,
Defendant.
New Nome” Nome Nene? meee” eee Nee” Nee” eee”
MEMORANDUM OPINION AND ORDER
Submitted: February 21, 2019
Decided: May 31, 2019
Upon Defendant’s Daubert Motion Regarding General Causation,
GRANTED, in part, and DENIED, in part.
Upon Defendant’s Motion for Summary Judgment Regarding Causation,
DENIED.
Upon Plaintiffs’ Daubert Motion to Strike Certain Opinions of
Defendant’s Expert Witnesses,
DENIED.
Raeann Warner, Esquire, Jacobs & Crumplar, P.A., Wilmington, Delaware, and
Jeffrey A. Travers, Esquire (argued), The Miller Firm, LLC, Orange, Virginia, and
Robin L. Greenwald, Esquire, Maja Jukic, Esquire, and Pearl A. Robertson, Esquire,
Weitz & Luxenberg P.C., New York, New York. Attorneys for Plaintiffs.
Kelly E. Farnan, Esquire and Katharine L. Mowery, Esquire, Richards, Layton &
Finger, P.A., Wilmington, Delaware, and Joe G. Hollingsworth, Esquire, Eric G.
Lasker, Esquire (argued), and Martin C. Calhoun, Esquire, Hollingsworth LLP,
Washington, D.C. Attorneys for Defendant.
MEDINILLA, J.
I. INTRODUCTION
Plaintiffs Joselin Barrera, Judi Fitzgerald, and Elias de la Garza (“Plaintiffs”)
filed claims alleging their cancer was caused by exposure to Defendant Monsanto
Company (“Monsanto”)’s glyphosate-based herbicide product, more commonly
known as Roundup. Monsanto moves under Delaware Rule of Evidence 702 to have
Plaintiffs’ experts’ opinions excluded for failure to satisfy Daubert v. Merrell Dow
Pharmaceuticals, Inc.,' and for summary judgment under Superior Court Civil Rule
56. Plaintiffs, conversely, move to strike certain opinions of Monsanto’s expert
witnesses under Daubert. After considering the parties’ written submissions,
supplemental submissions, and oral arguments, for the reasons stated below,
Defendant’s Daubert Motion is GRANTED, in part, and DENIED, in part,
Defendant’s Motion for Summary Judgment is DENIED, and Plaintiffs’ Daubert
Motion to Strike Certain Opinions of Defendant’s Expert Witnesses is DENIED.
Il. FACTUAL AND PROCEDURAL HISTORY
Monsanto manufactures the herbicide Roundup that contains glyphosate as an
active ingredient.” Monsanto initially discovered glyphosate’s herbicidal properties
in 1970.* Glyphosate became commercially available in 1974 after Monsanto began
' 509 U.S. 579 (1993) [hereinafter Daubert I].
2 See Def. Monsanto Co.’s Opening Br. in Support of its Daubert and Summ. J. Mots. Regarding
General Causation at 6 [hereinafter Def.’s Opening Br.].
3 Compl. § 20.
marketing it in its products, under the brand name Roundup.* By 2013, glyphosate
was the most widely used herbicide and Monsanto is its leading producer.°
Glyphosate-based herbicides (“GBHs”) are utilized across the country to control
weeds in agricultural and non-agricultural settings. A number of studies have been
conducted for glyphosate to determine its potential risk to human and environmental
health.’? The evaluation of glyphosate’s human carcinogenic potential has included
a review of epidemiological, animal carcinogenicity, and genotoxicity studies.*
Non-Hodgkin Lymphoma (“NHL”) affects white blood cells called
lymphocytes that are a part of the immune system.’ Of particular significance in this
case is whether glyphosate causes a particular type of cancer known as Non-Hodgkin
Lymphoma (“NHL”) in humans. This issue has sparked litigation across the
country.
A. National Procedural History — Multidistrict Litigation (“MDL”)
There are hundreds of lawsuits pending across the country in state and federal
courts wherein Plaintiffs allege their NHL diagnoses were caused by Monsanto’s
4 See Def.’s Opening Br. at 6; Compl. 1.
> Compl. Ff 1-2.
© EPA Office of Pesticide Programs, Revised Glyphosate Issue Paper: Evaluation of Carcinogenic
Potential at 12 (Dec. 12, 2017), https://www.regulations.gov/document?D=EPA-HQ-OPP-2016-
0385-0528 (“2017 EPA OPP”).
” Id. at 143.
8 Id.
9 American Cancer Society, About Non-Hodgkin Lymphoma at 1-2 (last revised Aug. 1, 2018),
https://www.cancer.org/content/dam/CRC/PDF/Public/8717.00.pdf.
3
herbicides. The MDL controls the federal cases to coordinate and centralize
management of these lawsuits. The MDL bifurcated the pretrial proceedings. The
first phase is the general causation phase; the second is the specific causation phase.
At issue in the present motions is the first phase considering general causation. The
general issue in this phase is whether glyphosate may cause NHL in humans at the
levels in which humans are generally exposed.
Monsanto and other plaintiffs filed similar motions in the United States
District Court in the Northern District of California (“MDL Court”). In March 2018,
the MDL Court held a Daubert hearing over seven days regarding the experts that
are expected to testify in this case.'? The MDL Court invited the State courts with
similar pending litigation to utilize this hearing within their own proceedings. The
parties in the case sub judice have relied upon the testimony provided at that hearing
and submitted the transcripts with their briefs.!!
In July 2018, the MDL Court issued a lengthy opinion addressing motions that
were before it.'* The MDL Court thoroughly discussed the underlying studies relied
upon by the parties’ experts, the scientific data provided therein, the expert testimony
from the Daubert hearing, the experts’ deposition testimony, and the experts’
'© There were additional experts who testified at the MDL Daubert hearing that are not at issue in
this proceeding.
"! Transcripts from the MDL Daubert hearing were provided by both parties, and this Court refers
to the transcript as a whole, regardless of which party submitted it, as Daubert Hearing Tr.
'? See generally In re: Roundup Products Liability Litigation, 2018 WL 3368534 (N.D. Cal. July
10, 2018) [hereinafter In re Roundup Litig. ].
reports.!3 The Court denied Monsanto’s motion for summary judgment after it
determined that some Plaintiffs’ experts’ opinions were admissible under Daubert.'*
The MDL Court denied plaintiffs’ Daubert motion to exclude the testimony of
Monsanto’s experts, finding that the experts used reliable scientific methodologies
and their opinions were admissible.'
The MDL Court’s opinion was then offered in these proceedings by Plaintiffs
in support of their positions. This Court is guided by the MDL Court and the
conclusions reached by that Court. As the parties relied upon the testimony provided
in the MDL Daubert hearing, this Court also defers to the MDL Court’s assessment
of the science and underlying studies.'®
B. Delaware Procedural History
Delaware has bifurcated pretrial proceedings consistent with the MDL Court.
On March 13, 2018, Monsanto filed these Daubert and Summary Judgment Motions
Regarding General Causation and its accompanying Opening Brief. On May 10,
2018, Plaintiffs filed their Response in Opposition to Defendant’s Daubert and
Summary Judgment Motion Regarding General Causation and their Daubert Motion
to Strike Certain Opinions of Defendant’s Expert Witnesses. Monsanto filed its
13 See generally In re Roundup Litig., 2018 WL 3368534.
14 See id. at *19-29, 36. The MDL Court found that at least some of the expert opinions of four of
Plaintiffs’ experts were admissible. That Court also held that the opinions of two of Plaintiffs’
experts were not admissible. Jd. at *29-33.
Td. at *33-35.
16 Td. at *8-17.
Reply Brief in Support of its Motions and Opposition to Plaintiffs’ Daubert Motion
on May 29, 2018. On June 12, 2018, Plaintiffs’ filed their Reply Brief. During the
course of these Daubert proceedings, both parties have submitted supplemental
authority for the Court to consider.'’ The Court heard oral argument on February
18, 2019.'® The matter is now ripe for review.
Ill. DAUBERT MOTIONS
Plaintiffs have retained six experts to offer opinions regarding general
causation. These retained experts are Dr. Beate Ritz, Dr. Dennis Weisenburger, Dr.
Christopher J. Portier, Dr. Charles W. Jameson, Dr. Alfred I. Neugut, and Dr. Chadi
Nabhan.'? These experts each opine similarly that glyphosates can cause NHL in
humans. Monsanto moves to exclude all of Plaintiffs’ experts. Monsanto has
retained its own experts, four of whom Plaintiffs seek to exclude—Dr. Jay I.
Goodman, Dr. Warren G. Foster, Dr. Jennifer R. Rider, and Dr. Lorelei A. Mucci.
Monsanto’s experts opine that the scientific evidence does not support a causal
7 On June 12, 2018, Monsanto submitted supplemental authority, which included a recent opinion
from the Fourth Circuit. On July 16, 2018, Plaintiffs submitted the MDL Court’s opinion on the
summary judgment and Daubert motions. On January 18, 2019, Monsanto provided the Court
with two additional pieces of evidence it considered relevant to its briefing. On February 13, 2019,
Plaintiffs submitted supplemental authority, which included a meta-analysis of the relevant
scientific studies. On February 21, 2019, Plaintiffs submitted additional correspondence
discussing the application of Daubert in the Third and Ninth Circuit courts.
'8 The Daubert briefing schedule and hearing date were modified due to the MDL Court’s
proceedings.
'? Plaintiffs have also designated two non-retained experts—Dr. Aaron Blair and Dr. Matthew
Ross.
relationship between glyphosate and NHL.
A. Daubert Standard
Delaware Rule of Evidence 702 addresses the admissibility of expert
testimony, and provides:
A witness who is qualified as an expert by knowledge, skill, experience,
training, or education may testify in the form of an opinion or otherwise
if: (a) the expert's scientific, technical, or other specialized knowledge
will help the trier of fact to understand the evidence or to determine a
fact in issue; (b) the testimony is based on sufficient facts or data; (c)
the testimony is the product of reliable principles and methods; and (d)
the expert has reliably applied the principles and methods to the facts
of the case.”°
This rule is nearly identical to Federal Rule of Evidence 702.7! In Daubert, the
Supreme Court interpreted Federal Rule of Evidence 702 and addressed the
admissibility of expert testimony.”” The Delaware Supreme Court has adopted the
holdings of Daubert and its progeny “as the correct interpretation of Delaware Rule
of Evidence 702.”
To determine the admissibility of scientific evidence consistent with Daubert,
the trial judge must determine whether:
(1) the witness is qualified as an expert by knowledge, skill experience,
training or education;
0 D.R.E. 702.
21 See Tumlinson v. Advanced Micro Devices, Inc., 81 A.3d 1264, 1269 (Del. 2013) [hereinafter
Tumlinson IT].
22 See generally Daubert I, 509 U.S. at 579.
23 MG. Bancorporation v. LeBeau, 737 A.2d 513, 522 (Del. 1999).
7
(2) the evidence is relevant;
(3) the expert's opinion is based upon information reasonably relied
upon by experts in the particular field;
(4) the expert testimony will assist the trier of fact to understand the
evidence or to determine a fact in issue; and
(5) the expert testimony will not create unfair prejudice or confuse or
mislead the jury.”*
A trial judge serves as a gatekeeper to determine if the expert testimony is
both relevant and reliable.*> In doing so, a judge must decide “whether an expert’s
testimony ‘has a reliable basis in the knowledge and experience of [the relevant]
discipline.””*® While acting as a gatekeeper and determining the reliability of the
expert testimony, the trial court should consider the following non-exhaustive
factors:
(1) whether a theory or technique has been tested;
(2) whether it has been subjected to peer review and publication;
(3) whether a technique had a high known or potential rate of error and
whether there are standards controlling its operation; and
(4) whether the theory or technique enjoys general acceptance within a
relevant scientific community.?’
This list of factors is not a definitive checklist.2* The Daubert analysis focuses
on “the principles and methodology used in formulating an expert’s testimony, not
** Bowen v. E.I. DuPont de Nemours & Co., Inc., 906 A.2d 787, 795 (Del. 2006).
*° See Tumlinson II, 81 A.3d at 1269 (citing Kumho Tire Co. v. Carmichael, 526 U.S. 137, 141
(1999).
6 Bowen, 906 A.2d at 794 (quoting LeBeau, 737 A.2d at 523).
27 Id. (quoting Daubert I, 509 U.S. at 590-94).
*8 Scaife v. Astrazeneca LP, 2009 WL 1610575, at *14 (Del. Super. June 9, 2009) (quoting Kumho
Tire, 526 U.S. at 150) (internal quotations omitted).
8
on the expert’s resultant conclusions.””? The trial judge must assess “whether the
reasoning or methodology underlying the testimony is scientifically valid
and...whether that reasoning or methodology properly can be applied to the facts in
issue.”3°
The Delaware Supreme Court has explained that “an expert’s methodology
must be not only reliable intrinsically but also be reliably applied to the facts of the
31 The evidence must have “a valid scientific connection to the
specific case.
pertinent inquiry as a precondition to admissibility,”3” which is described as the “fit”
requirement.*?> As to general causation, the inquiry is “whether a substance is
capable of causing a particular injury or condition in the general population.”** An
expert’s opinions “cannot be based simply on the ipse dixit of the expert.”*’ The
burden of establishing that expert testimony is admissible is on the party proffering
it by a preponderance of the evidence.*®
Albeit dense information, the Court is compelled to provide an overview of
29 Bowen, 906 A.2d at 794 (citing Daubert I, 509 U.S. at 595) (internal quotations omitted).
39 Daubert I, 509 U.S. at 592-93.
31 Scaife, 2009 WL 1610575, at *15 (quoting General Motors Corp. v. Grenier, 2009 WL 267665,
at *4 (Del. Feb. 4, 2009)).
32 In re Asbestos Litig., 911 A.2d 1176, 1199 (Del. Super. 2006) (quoting Daubert I, 509 U.S. at
592).
33 Id.
34 Smith v. Benjamin Moore & Co., 2012 WL 2914219, at *2 (Del. Super. July 18, 2012) (quoting
Georgia-Pacific Corp. v. Bostic, 320 S.W.3d 588, 595 (Tex. App. 2010)).
35 Minner v. American Mortg. & Guar. Co., 791 A.2d 826, 839 (Del. Super. 2000) (citing General
Electric Company v. Joiner, 522 U.S. 136, 146 (1997)).
36 Scaife, 2009 WL 1610575, at *15 (citing Bowen, 906 A.2d at 795); see Minner, 791 A.2d at 843.
9
the general concepts and science applicable to the experts’ opinions to better explain
this Court’s determination under Daubert.
B. Epidemiology
1. Epidemiology Overview and Bradford-Hill Criteria
Epidemiology “is the science of the relationship between human behaviors
and patterns, causes, and effects of diseases across the population.”3” It focuses on
general causation, at issue in these motions.*® It is common that “plaintiffs find
epidemiological studies indispensable in toxic tort cases when direct proof of
causation is lacking.”%? General causation considers the possibility that a certain
exposure caused a certain harm, not the likelihood that it did.’° If epidemiology is
being offered to support general causation, “a less stringent standard is, by
definition, weaker but potentially probative.”*! The burden is not on the plaintiff to
“find a flawless, all-inclusive epidemiological study mirroring their precise
circumstances.””? A plaintiff does not have to support her general causation case
with epidemiology evidence as a matter of law.”
37 Tumlinson v. Advanced Micro Devices, Inc., 2013 WL 7084888, at *4 (Del. Super. Oct. 15,
2013), aff'd 81 A.3d 1264 (Del. 2013) [hereinafter Tumlinson I].
38 [d. (citation omitted).
3° Td. (quotation and citation omitted).
49 Id. at *5.
“! Td. at *6 (differentiating between epidemiology being offered to support specific causation and
general causation).
” Tumlinson, 2013 WL 7084888, at *7 (citation omitted).
3 In re Asbestos Litig., 911 A.2d at 1209.
10
Epidemiology demonstrates an association, after which epidemiologists rely
on what is known as the Bradford-Hill criteria to assess whether a causal relationship
can be inferred from that association. The Bradford-Hill factors include: “1)
temporal relationship, 2) strength of the association, 3) dose-response relationship,
4) replication of the findings, 5) biological plausibility, 6) consideration of
alternative explanations, 7) cessation of exposure, 8) specificity of the association,
and 9) consistency with other knowledge.”*° Evidence such as animal studies, in
vivo studies, in vitro studies, toxicology, and case studies “can be used together to
show causation.”*° An epidemiologist’s methods used “to form an opinion as to
causation substantially rely on the expert’s judgment in selecting and weighing her
sources.”*” In order to establish reliability, the expert must “clearly define her
methodology and application.”4* In the epidemiology field, an analysis of the
Bradford-Hill criteria is a generally accepted method of evaluating scientific
evidence.’? Of particular importance in this case is how the experts weighed the
44 Tumlinson I, 2013 WL 7084888, at *9; In re Roundup Litig., 2018 WL 3368534, at *7
(explaining when epidemiologists utilize the Bradford Hill criteria to assess causation).
45 Tumlinson I, 2013 WL 7084888, at *9 (outlining the Bradford Hill factors and explaining that
they are not all-inclusive and only establish a framework to establish causation) (citation omitted).
46 Id.
47 Td. at *6.
48 Id.
49 See In re Roundup Litig., 2018 WL 3368534, at *18 (citing Daubert v. Merrell Dow
Pharmaceuticals, Inc., 43 F.3d 1311, 1316 (9th Cir. 1995) [hereinafter Daubert II]; Lust By &
Through Lust v. Merrell Dow Pharmaceuticals, Inc., 89 F.3d 594, 597 (9th Cir. 1996)).
11
Bradford-Hill criteria and whether these assessments are reliable.
Here, the parties disagree as to whether statistical significance is a threshold
before applying the Bradford-Hill criteria. Monsanto argues a statistically
significant association must be shown in the epidemiology before experts can
consider the Bradford-Hill factors, relying on Tumlinson I and In re Zoloft
(Sertraline Hydrochloride) Products Liability Litigation,' and contends Plaintiffs
do not meet this threshold requirement. Plaintiffs argue that statistical significance
is not required before conducting the Bradford-Hill analysis. Regardless, Plaintiffs
contend that because the epidemiology here represents a statistically significant
association, their experts appropriately proceeded to conduct the Bradford-Hill
analysis on the issue of causation.
This Court is guided by the Superior Court in Tumlinson I that discusses
epidemiology and the requirements of admissibility of evidence to establish general
causation.** That Court looked to other jurisdictions to determine the standard for
the admissibility of epidemiology opinions under Daubert in Delaware. In
analyzing the admissibility of the proffered expert’s opinion on epidemiological
studies, the Court stated that “the first question is whether the foundational study
°° In re Roundup Litig., 2018 WL 3368534, at *18.
>! 858 F.3d 787 (3d Cir. 2017) [hereinafter In re Zoloft).
°2 See Tumlinson I, 2013 WL 7084888, at *4-10 (finding the experts’ opinions were unreliable
under Daubert and inadmissible). The Delaware Supreme Court affirmed the trial court’s
exclusion of the expert testimony as unreliable. See Tumlinson II, 81 A.3d at 1270-73.
>3 See Tumlinson I, 2013 WL 7084888, at *4-6.
12
shows a statistically significant association.” The Tumlinson I Court then provides
that “a study must demonstrate some positive association in order to have value as
part of a larger meta-analysis.”*° In other jurisdictions, including the Third Circuit
in In re Zoloft, statistical significance is not a threshold requirement before an expert
may conduct the Bradford-Hill analysis.°° It stated:
A causal connection may exist despite the lack of significant findings,
due to issues such as random misclassification or insufficient power.
Conversely, a causal connection may not exist despite the presence of
significant findings. If a causal connection does not actually exist,
significant findings can still occur due to, inter alia, inability to control
for a confounding effect or detection bias. A standard based on
replication of statistically significant findings obscures the essential
issue: a causal connection....Despite the problems with treating
statistical significance as a magic criterion, it remains an important
metric to distinguish between results supporting a true association and
those resulting from mere chance. Discussions of statistical
significance should thus not understate or overstate its importance.”
The Third Circuit did not establish a bright-line rule requiring statistical
significance to prove causality.°* This Court agrees. Even if statistical significance
54 Tumlinson I, 2013 WL 7084888, at *10 (citing Heller v. Shaw Indus., Inc., 167 F.3d 146, 220
(3d Cir. 1999)).
55 Id.
°6 See In re Zoloft, 858 F.3d at 794 (noting that the District Court rejected the argument “that the
existence of a statistically significant, replicated result is a threshold issue before an expert can
conduct the Bradford-Hill analysis” and did not require a threshold showing of statistical
significance); In re Joint Eastern & Southern Dist. Asbestos Litig., 52 F.3d 1124, 1134 (2d Cir.
1995) (“We believe that it would be far preferable for the district court to instruct the jury on
statistical significance and then let the jury decide whether many studies over the 1.0 mark have
any significance in combination.”). But see Tumlinson I, 2013 WL 7084888, at *6 (“It also makes
sense to require that the entire confidence interval show a positive association—a relative risk over
1.0—to demonstrate that there is a positive association expected at least 95% of the time.”).
ai In re Zoloft, 858 F.3d at 793 (citations omitted).
8 Id.
13
was a threshold requirement here, Plaintiffs’ experts rely on various studies, some
that show statistically significant associations or positive associations. Thus,
Plaintiffs’ experts have sufficiently demonstrated a basis for evaluations of the
Bradford-Hill criteria.
2. Case-Control Studies, Meta-Analyses, and Cohort Studies
The parties’ experts rely on scientific evidence, including case-control studies,
meta-analyses, and cohort studies. And the science gets denser.
Case-control studies involve subjects that are included based on their disease
status.°? The study includes subjects who have the disease and those who do not.
A pooled analysis combines the raw data from multiple studies and examines the
data as a single dataset.’ The parties’ experts here relied upon multiple case-control
studies.°
°° Pls.’ Ex. 5, Expert Report of Dr. Beate Ritz, M.D., Ph.D. in Support of General Causation on
Behalf of Plaintiffs at 2 [hereinafter Dr. Ritz Report].
6° Id, at 2-3.
6! Td. at 6.
® The following is an overview of some, but not all, of the studies reviewed by the experts. The
McDuffie (2001) study was a case-control study from Canada. Pls.’ Ex. 15, A.J. De Roos, et al.,
Integrative Assessment of Multiple Pesticides as Risk Factors for Non-Hodgkin’s Lymphoma
Among Men, 60 Occup. Environ. Med. 1 (2003) [hereinafter De Roos (2003)]. In this study, NHL
diagnoses occurred between 1991 and 1994. Jd. at 1156. There were 51 cases of NHL exposed to
glyphosate and 133 controls exposed to glyphosate. See id. at 1158. In order to compute the odds
ratios and the 95% confidence intervals, a conditional logistic regression was utilized. Id. at 1157.
The overall adjusted odds ratio for glyphosate was reported at 1.2 with a 95% confidence interval
of 0.83 to 1.74. Id at 1158. Hereinafter, the 95% confidence interval will be provided as the
following: odds ratio (lower point-higher bound). The odds ratio was adjusted for other medical
variables, including a history of certain diseases, allergy desensitization shots, a positive family
history of cancer, age, and province of residence, but not for the use of other pesticides. See id
Additionally, the study reported that for zero to two days of exposure to glyphosate per year the
14
Case-control studies report odds ratios “as the measure of association between
the variables the investigators are studying.” An odds ratio is a measure of an
odds ratio was 1.00 (0.63-1.57). Id. at 1161. The study stated that when there was glyphosate
exposure of more than two days per year, the odds ratio was 2.12 (1.20-3.73). Id Overall, the
study reported that its results supported prior findings of an association between NHL and
exposure to certain pesticides. Jd. at 1162.
The De Roos (2003) study was a pooled analysis of three case-controlled studies. Pls.’ Ex.
15, A.J. De Roos, et al., Integrative Assessment of Multiple Pesticides as Risk Factors for Non-
Hodgkin’s Lymphoma Among Men, 60 Occup. Environ. Med. 1 (2003) [hereinafter De Roos
(2003)]. De Roos (2003) analyzed the effect of exposure to pesticides on the incidence of NHL,
focusing only on men. Jd. at 1. In De Roos (2003), the authors examined 47 different pesticides,
including insecticides and herbicides. Jd. at 2. The study utilized both standard logistic regression
and hierarchical regression to calculate the odds ratios and estimate the risk associated with each
pesticide. Id. Using the logistic regression model, the odds ratio for glyphosate was 2.1 (1.1-4.0).
Id. at 5. Using the hierarchical regression model, the odds ratio for glyphosate was 1.6 (0.9-2.8).
Id. These effect estimates adjusted for the use of all other pesticides in the study. Jd.
The Eriksson (2008) study assessed exposure to pesticides and NHL, with the cases of
NHL collected between 1999 and 2002. Pls.’ Ex. 19, Erik Eriksson, et al., Pesticide Exposure as
Risk Factor for Non-Hodgkin Lymphoma Including Histopathological Subgroup Analysis, 123 Int.
J. Cancer 1657 (2008) [hereinafter Eriksson (2008)]. Under the univariate model, the authors
reported glyphosate exposure at an overall odds ratio of 2.02 with a 95% confidence interval of
1.10 to 3.71. Id. at 1658, 1659. For those exposed to glyphosate for ten days or less, the odds ratio
was reported at 1.69 (0.70-4.07). Id. at 1659. For greater than ten days of exposure to glyphosate,
the odds ratio was 2.36 (1.04-5.37). Id. When there was greater than ten years of latency, the odds
ratio was 2.26 (1.16-4.40). Id. For those who developed cancer less than 10 years after exposure,
the odds ratio was 1.11 (0.24-5.08). Id. A multivariate analysis was performed, and yielded an
odds ratio of 1.51 (0.77-2.94) for glyphosate. Jd. at 1661. Eriksson (2008) concluded that the
results strengthened its previous indication “of an association between glyphosate and NHL.” Jd.
at 1662.
The North American Pooled Project (“NAPP”) (2015) study is a pooled analysis of three
case-control studies that were included in McDuffie (2001) and De Roos (2003). Daubert Hearing
Tr. at 218:25-219:5. The results of this study are not published in a peer-reviewed journal. NAPP
(2015) assessed the associations between exposure to glyphosate and NHL. Pls.’ Ex. 25, Manisha
Pahwa, et al., An Evaluation of Glyphosate Use and the Risk of Non-Hodgkin Lymphoma Major
Histological Sub-Types in the North American Pooled Project (NAPP) at 2 (Sept. 21, 2015). The
study reported an odds ratio of 1.51 (1.18-1.95) for overall exposure to glyphosate. See Pls.’ (1)
Resp. in Opp. to Def.’s Daubert and Summ. J. Mot. Regarding General Causation and (2) Daubert
Mot. to Strike Certain Opinions of Def.’s Expert Witnesses at 18 [hereinafter Pls.” Answering Br.];
Pls.’ Ex. 23. Pahwa, Manisha, et al., 4n Evaluation of Glyphosate Use and the Risks of Non-
Hodgkin Lymphoma Major Histological Sub-Types in the North American Pooled Project (NAPP),
International Society for Environmental Epidemiology, (Aug. 31, 2016).
63 In re Roundup Litig., 2018 WL 3368534, at *8.
15
association between exposure to an agent, like glyphosate, and a disease, like NHL,
that is expressed in quantitative terms. “In a case-control study, the odds ratio is
the ratio of the odds that a case (one with the disease) was exposed to the odds that
a control (one without the disease) was exposed.”© If the odds ratio is greater than
1.0, then it indicates an association.
Confidence intervals generally accompany odds ratios. The standard
interval—95% confidence interval—sets forth a range of error. The confidence
interval provides “a range (interval) within which the risk likely would fall if the
study were repeated numerous times.”°’ With a 95% confidence interval, the range
includes “the results we would expect 95% of the time if samples for new studies
were repeatedly drawn from the same population.”®® This confidence interval
“means that there is a 95% chance that the ‘true’ odds ratio value falls within the
confidence interval range.” The ratio is considered statistically significant “if the
lower bound of the confidence interval is greater than onef[.]” Statistical
significance is used to determine if there is a relationship between certain factors or
4 Michael D. Green et al., Reference Guide on Epidemiology, in Reference Manual on Scientific
Evidence 551, 568 (3d ed. 2011) [hereinafter Reference Manual].
69 Id.
6 See In re Roundup Litig., 2018 WL 3368534, at *8.
67 Reference Manual at 573.
68 Id. at 580.
© In re: Zoloft (Sertraline Hydrocloride) Products Liability Litig., 2015 WL 7776911, at *2 (E.D.
Pa. Dec. 2, 2015).
70 Id.
16
if the outcome of a study resulted from chance.
Another important concept to epidemiology is known as confounding.
“Confounding occurs when another causal factor (the confounder) confuses the
relationship between the agent of interest and outcome of interest.”’' An “instance
of confounding is when a confounder is both a risk factor for the disease and a factor
associated with the exposure of interest.”’”” A researcher must determine whether an
association between an agent and a disease “is causal or the result of confounding.””*
Another form of studies is known as meta-analyses. Meta-analyses are used
to combine multiple studies’ results.’ “Meta-analysis is a method of pooling study
results to arrive at a single figure to represent the totality of the studies reviewed.”
The studies in a meta-analysis are given different weights, depending on the size of
the study populations and other characteristics.”° Rather than using the raw data like
in pooled analyses, meta-analysis uses the “[o]dds [rJatios or [rate [rJatios and
confidence intervals which were published in the original studies.””’ A rate ratio
“compares the incidence rates of disease given an exposure, to the incidence rate of
disease among people without the exposure.””® The experts here also rely on meta-
™! Reference Manual at 591 (citation omitted).
72 Id
73 Id.
74 Td. at 581, n.89.
73 Td. at 607.
76 Reference Manual at 607.
™ Tr. Ritz Report at 6.
78 Td. at 4.
17
analyses to support their opinions, including Schinasi and Leon (2014),”? Chang and
Delzell (2016),®° and IARC.®!
Finally, there are cohort studies. A cohort study involves “groups of
individuals [that] can be identified who are, have been, or in the future may be
differentially exposed to an agent or agents hypothesized to influence the incidence
” Pls.’ Ex. 30, Leah Schinasi and Maria E. Leon, Non-Hodgkin Lymphoma and Occupational
Exposure to Agricultural Pesticide Chemical Groups and Active Ingredients: A Systemic Review
and Meta-Analysis, 11 Int. J. Environ. Res. Public Health 4449 (2014) [hereinafter Schinasi and
Leon (2014)].
®° Pls.’ Ex. 31, Ellen T. Chang and Elizabeth Delzell, Systemic Review and Meta-Analysis of
Glyphosate Exposure and Risk of Lymphohematopoietic Cancers, 51 J. of Environ. Science and
Health 402 (2016) [hereinafter Chang and Delzell (2016)].
8! TARC, Some Organophosphate Insecticides and Herbicides: Diazinon, Glyphosate, Malathion,
Parathion, and Tetrachlorvinphos, Monograph Vol. 112 on the Evaluation of Carcinogenic Risks
to Humans at 1 (2015), http://monographs.iare.fr/ENG/Monographs/vol112 /monol12-10.pdf
[hereinafter IARC Monograph]. See generally IARC, IARC Monographs on the Evaluation of
Carcinogenic Risk to Human Preamble [hereinafter IARC Preamble]. In 2015, the International
Agency for Research on Cancer (“IARC”), a subdivision of the World Health Organization
(“WHO”), initiated a working group to examine the association between glyphosate and cancer.
This working group created a “Monograph” to evaluate scientific data and studies and determined
that glyphosate was “probably carcinogenic to humans.” [ARC Monograph at 78.
The IARC Monograph (2015), relied upon heavily by Plaintiffs, examined glyphosate
exposure and the incidence of cancer in humans. See generally id. The IARC discussed numerous
cohort studies and case-control studies relating to glyphosate exposure in humans and examined
animal studies and other available data. See generally id.
The IARC concluded that there is “limited evidence in humans for the carcinogenicity of
glyphosate,” which means that a “positive association has been observed between exposure to the
agent and cancer for which a causal interpretation is considered by the Working Group to be
credible, but chance, bias or confounding could not be ruled out with reasonable confidence.” Id.
at 78; IARC Preamble at 19-20. As to carcinogenicity in experimental animals, the IARC
concluded that there was sufficient evidence, meaning “that a causal relationship has been
established between the agent and an increased incidence of malignant neoplasms or of an
appropriate combination of benign and malignant neoplasms” in animal studies. IARC
Monograph at 78; IARC Preamble at 20. IARC found overall that glyphosate is probably
carcinogenic to humans and labeled glyphosate as a Group 2A agent, which is the classification
for when “there is limited evidence of carcinogenicity in humans and sufficient evidence of
carcinogenicity in experimental animals.” IARC Monograph at 78; IARC Preamble at 22.
18
of occurrence of a disease or other outcome.”®? Here, the cohort study deals with
exposure to glyphosate and the incidence of the occurrence of NHL.”
In this case, the experts relied upon a number of these various types of studies
to formulate their opinions. The MDL Court addressed a number of these studies,
explaining the methods used by the authors and their results.8* The Court has
reviewed the epidemiological evidence and the experts’ respective reports applicable
to this litigation that were presented as exhibits to the pleadings, including the case-
control studies, meta-analyses, and cohort study. The Court has also examined the
MDL Court’s assessment of the underlying epidemiology evidence.
Overall, as to both parties, some of the epidemiology studies suggest an
association between glyphosate exposure and NHL, whereas other studies do not.8>
82 Reference Manual at 621.
83 Monsanto relies on the Agricultural Health Study cohort study (“AHS Cohort”) that it argues
comports with the Daubert factors for reliability to support that there is no association between
glyphosate exposure and NHL. Def.’s Ex. 17, Gabriella Andreotti, et al., Glyphosate Use and
Cancer Incidence in the Agricultural Health Study, 110 J. Nat’! Cancer Inst. 1 (published online
Nov. 17, 2017) [hereinafter AHS Cohort]. The AHS observed no association between glyphosate
use and NHL. /d at 7. This study considered glyphosate use that was reported at enrollment
between 1993 and 1997. Jd. at2. During that time period, over 57,000 individuals seeking licenses
to apply certain pesticides were enrolled. Jd. The AHS cohort study ascertained use of fifty
pesticides, including glyphosate. Jd. Five years after the enrollment, 63% of the participants
completed a follow up phone interview between 1999 through 2005. Id. Cancer registries in lowa
and North Carolina provided information about cancer diagnoses of participants. Id. The study
adjusted for several factors including, but not limited to, age, cigarette smoking status, alcohol
drinks per month, and family history of cancer. Id.
The AHS cohort reported four rate ratios based on the lifetime days of exposure in regards
to glyphosate use and the incidence of NHL. Jd. at 2,5. The quartile with the highest number of
lifetime days of glyphosate use reported a rate ratio of 0.87 (0.64-1.20). Id. at 5.
84 See In re Roundup Litig., 2018 WL 3368534, at *9-10 (outlining the frequently discussed case-
control studies).
85 Id. at *1,
19
Based on an extensive assessment of the epidemiological studies, the MDL Court
found that “[a]ll the studies leave certain questions unanswered, and every study has
its flaws.”*° Although confounding of exposure to other pesticides is a concern in
the case-control studies, the studies relied upon by the experts adjusted for different
confounders to varying degrees.*’
In sum, “the epidemiology evidence is open to different interpretations, and
the potential flaws in the data from the case-control studies and meta-analyses are
not overwhelmingly greater than the potential flaws in the data from the [cohort]
study.”* Experts operating on reliable scientific principles could weigh the studies
differently “and could conclude that the analyses of the case-control studies support
an association between glyphosate exposure and NHL, even if this is not necessarily
the best interpretation of the evidence.”®? This Court finds no reasons to disturb the
MDL Court’s assessment of the merits of the epidemiological studies. Thus, an
expert cannot be excluded as unreliable for weighing the case-control studies more
favorably than the cohort study.”
C. Laboratory Animal Carcinogenicity Studies
Plaintiffs’ experts also rely on animal carcinogenicity studies to form their
86 In re Roundup Litig., 2018 WL 3368534, at 1.
87 Td. at *13.
88 Td. at *15.
8° Td. (citing Daubert II, 43 F.3d at 1317).
See id.
20
opinions on general causation. Monsanto argues that many of Plaintiffs’ experts are
not qualified to opine about rodent carcinogenicity data.*' As to the experts that
Monsanto contends are qualified, it argues that they are unable to link the animal
data results regarding glyphosate and NHL to the human condition.” Further,
Monsanto contends that the experts’ opinions are based upon unsound scientific
principles.”
The animal carcinogenicity evidence advances a material aspect of Plaintiff's
case” because the animal bioassays are germane to the biological plausibility factor
of the Bradford-Hill analysis.”> Plaintiffs argue that glyphosate can cause NHL in
humans and the animal carcinogenicity studies that demonstrate that glyphosate is
carcinogenic in rodents logically advances this argument.”® These experts do not
rely solely upon animal studies to establish general causation. They also discuss
epidemiological evidence and mechanistic data. The animal carcinogenicity
evidence will assist the trier of fact to understand an issue in this case and has a valid
scientific connection to the issues here.?’
*! Def.’s Opening Br. at 22, n.42.
% Id. at 22-24.
3 See id. at 24-40.
%4 See Daubert IT, 43 F.3d at 1315. Ensuring that the expert’s proposed testimony “is relevant to
the task at hand” is known as the “fit” requirement. Jd. (citations omitted).
% See Inre Roundup Litig., 2018 WL 3368534, at *15.
%6 See Tumlinson I, 2013 WL 7084888, at *9 (“Other forms of evidence including toxicology, in
vivo studies, in vitro studies, animal studies, and case studies can be used to show causation.”)
7 See In re Asbestos Litig., 911 A.2d at 1199 (citations omitted).
21
D. Mechanistic Data
Plaintiffs also try to submit evidence regarding mechanistic data, including
genotoxicity evidence and oxidative stress. This type of evidence involves whether
certain chemicals, like glyphosate, can cause changes at the cellular level that could
cause cancer.”°
Monsanto argues this type of data does not meet Daubert’s “fit”
requirement, is not scientifically reliable, and should only be considered when
scientifically sound human data is unavailable.”
Delaware law does not require that evidence of general causation take the
form of epidemiological evidence.'®° Other types of scientific evidence may suffice
to establish general causation if it is relevant and reliable.'"' Here, Plaintiffs’ experts
rely on two studies—Bolognesi (2009) and Paz-y-Mino (2007).'° Monsanto
contends that these studies’ methodologies are flawed, and any opinions formed
based on reliance on these studies must be excluded. Bolognesi (2009) conducted a
cytogenetic biomonitoring study from five regions in Colombia to evaluate
genotoxic effect of aerial spraying of glyphosate.’ This study used both ecological
°8 In re Roundup Litig., 2018 WL 3368534, at *17.
” See Def.’s Opening Br. at 40-45.
100 In re Asbestos Litig.,911 A.2d at 1209.
101 Id
'® See Pls.’ Ex. 73, C. Bolognesi, et al., Biomonitoring of Genotoxic Risk in Agricultural Workers
from Five Colombian Regions: Association to Occupational Exposure to Glyphosate, 72 J.
Toxicology Envtl. Health, Part A 986 (2009) [hereinafter Bolognesi (2009)]; Pls.’ Ex. 72, C. Paz-
y-Mino, et al., Evaluation of DNA Damage in an Ecuadorian Population Exposed to Glyphosate,
30 Genetics and Molecular Biology 453 (2007) [hereinafter Paz-y-Mino (2007)].
103 Bolognesi (2009) at 988.
22
and self-reported approaches to characterize exposure to glyphosate, and the authors
104 Paz-
noted that the ecological method may cause misclassification of exposures.
y-Mino (2007) performed a study to analyze the impact of glyphosate used in aerial
spraying in norther Ecuador on the impacted individual’s genetic material.'™
Although epidemiology has been presented by both sides, other types of
scientific evidence, such as mechanistic data involving genotoxicity, is relevant to
the biological plausibility prong of the Bradford-Hill analysis. This Court finds
Plaintiffs’ experts’ opinions on mechanistic data are relevant and meet Daubert’s
“fit” requirement. The Court will now consider the admissibility of the experts’
opinions.
IV. MONSANTO’S DAUBERT MOTION
Before addressing the parties’ respective experts, it is important for the Court
to reiterate that “Daubert permits testimony that is the product of competing
principles or methods in the same field of expertise.”'°° Further, the courtroom is
not intended to be a scientific laboratory and the “judge is not a scientist.”!°’ The
Court’s analysis under Daubert is focused on the principles and methodologies
employed by the experts in creating their opinions, not on the experts’
104 Bolognesi (2009) at 995.
105 Paz-y-Mino (2007) at 456-57.
106 In re Asbestos Litig., 911 A.2d at 1201 (citing Heller, 167 F.3d at 160).
107 See id. at 1199 (citation omitted).
23
conclusions. !°%
The Court’s role is to determine that the expert’s opinion is
sufficiently reliable, will assist the trier of fact to understand the evidence, and will
not create unfair prejudice or mislead the jury.'” The reliability requirement is not
a tool for the Court to use to exclude questionably reliable evidence.!!°
A. Dr. Ritz
Dr. Ritz is a Professor of Epidemiology at the UCLA Fielding School of
Public Health.'"' Dr. Ritz holds a Ph.D. in epidemiology and an MD.!!? Her primary
research interests focus on the health effects of environmental and occupational
exposures. !!3
There is no dispute that Dr. Ritz is qualified to opine about the
epidemiology evidence at issue in this case.
Dr. Ritz opines that Roundup is capable of causing NHL.'!* Dr. Ritz reviewed
numerous epidemiologic studies and examined how these studies worked
together.'!” The studies she identified included the NAPP, IARC Monograph,
Eriksson (2008), and De Roos (2003).'!® Dr. Ritz also evaluated the Bradford-Hill
criteria. Proceeding to the Bradford-Hill analysis, she found that the strength
08 See Bowen, 906 A.2d at 794 (discussing focus of Daubert analysis).
109 See id.
'!° See Tumlinson I, 2013 WL 7084888, at *2 (quoting United States v. Velasquez, 64 F.3d 844,
850 (3d Cir. 1995).
"ll Dr, Ritz Report at 1.
M2 7g
113 Id.
'l4 Daubert Hearing Tr. at 95:19-25.
115 Dr, Ritz Report at 14-15.
16 Tq. at 15-23.
24
criterion was “partially met” given that the meta-analytical effect estimates reflected
“a weak to moderate size association.”!'’ Dr. Ritz found that the dose-response,
consistency, and temporality criteria were met.'’®
Dr. Ritz stated that the specificity criterion is difficult to apply in cases like
these involving pesticide or herbicide exposure because most people who work with
119 In terms of biological
these products are not exposed solely to glyphosate.
plausibility, Dr. Ritz concluded that this criterion was met.'”° As to the coherence
criterion, Dr. Ritz explained that “there will never be any human experimental
evidence for glyphosate toxicity or carcinogenicity....”!?"
Dr. Ritz relied on mechanistic evidence in her report to support the biological
plausibility that a causal connection between glyphosate and NHL exists.” She
noted that two mechanisms—oxidative stress and genotoxicity—have been
proposed recently for glyphosate and provided brief summaries of studies that
confirm this.'23 Dr. Ritz found that the epidemiologic studies support “an increased
risk of NHL with exposure to glyphosate or glyphosate based formulations,
including Roundup.”!*4 Ultimately, Dr. Ritz concluded to a reasonably degree of
7 Dr, Ritz Report at 23.
18 Td at 23-24.
19 Tq at 24.
120 Td. at 24-25.
121 Tq at 25.
122 Dr. Ritz Report at 24-25.
123 Td at 25.
124 Id.
25
scientific certainty that glyphosate and glyphosate-based formulations cause
NHL. '25
Monsanto argues that Dr. Ritz has changed her opinion on the epidemiological
evidence, after initially relying on reported confounded odds ratio but later
distancing herself from the study results because the adjusted data did not show an
association between glyphosate and NHL. This goes to the weight of the evidence,
not admissibility. While it is true that Dr. Ritz emphasized unadjusted numbers in
her report, her analysis also considered adjusted numbers. Some of the meta-
analyses relied upon by Dr. Ritz included fully adjusted estimates and some of the
studies adjusted for other pesticides.!”6
Dr. Ritz’s opinion is relevant to general causation and whether glyphosate can
cause NHL in humans at realistic levels to which they are exposed. The principles
and methodology underlying Dr. Ritz’s opinion are scientifically valid and can be
properly applied to this case. Her opinion provides sufficient specificity to satisfy
Daubert’s testability factor. Also, Dr. Ritz relied upon peer-reviewed studies and
literature. She conducted a Bradford-Hill analysis, which is a technique relied upon
by epidemiologists to establish causation,!?’ and sufficiently articulated her
125 Dr, Ritz Report at 25.
126 Td. at 16, 19.
'°7 See Tumlinson I, 81 A.3d at 1272 (explaining that epidemiologists rely on two methods to
establish causation—Bradford-Hill analysis and weight-of-the-evidence analysis).
26
evaluation methods to establish reliability. Dr. Ritz’s opinions on the epidemiology
evidence are admissible and her assessment of the Bradford-Hill criteria is
admissible to the extent it is limited to her role as an epidemiologist performing this
analysis.!28 Dr. Ritz’s expert opinion satisfies the Daubert requirements for
reliability; therefore, her opinion is admissible under D.R.E. 702.
B. Dr. Weisenburger
Dr. Weisenburger is a hematopathologist; a physician and a pathologist that
studies diseases of the immune system, blood, and bone marrow, which includes
NHL.'?? His specialty includes studying the pathology, subtypes, genetics,
epidemiology, causes or etiologies, and clinical features of NHL.!3° Monsanto does
not dispute that Dr. Weisenburger is qualified to opine on epidemiology evidence."?'
Dr. Weisenburger’s report first addresses epidemiology in humans by
examining six published case-control studies, one cohort study, and three meta-
analyses.!3? After his brief review of the epidemiological data, Dr. Weisenburger
concluded that the studies provide evidence “for a relationship between glyphosate
128 See In re Roundup Litig., 2018 WL 3368534, at *27. Similar to the MDL Court, any “forest
plot” from Dr. Ritz’s report will not be presented to the jury because it is misleading. /d. at *26.
129 Daubert Hearing Tr. at 169:14-18.
130 Td. at 169:19-24. He is also a co-author of De Roos (2003).
131 See Def.’s Opening Br. at 12, n.18. Monsanto argues that Dr. Weisenburger is unqualified to
render opinions on rodent bioassay data or mechanistic data. See id. at 22, n.42 and 43, n.71.
132 pls.’ Ex. 10, Expert Report of Dr. Dennis Weisenburger, M.D. in Support of General Causation
on Behalf of Plaintiffs at 4-6 [hereinafter Dr. Weisenburger Report].
27
exposure and risk of NHL....”!*
He also discusses animal studies, where the carcinogenicity of glyphosate has
been tested in rodents, and the mechanisms of carcinogenesis.'3* Dr. Weisenburger
concurred with the findings of three animal studies that there were positive findings
of carcinogenicity for glyphosate.'*> He further concurred with IARC findings that
glyphosates are genotoxic.'*° Dr. Weisenburger conducted a Bradford-Hill analysis
and concluded that glyphosate can cause NHL in humans.'37 He opines that
glyphosate may cause NHL in humans at exposure levels that people are currently
experiencing. !38
Experts may rely on more than just the epidemiology studies to support their
opinions, including animal studies and mechanistic data. As to Dr. Weisenburger’s
opinion on the epidemiology evidence, this Court finds that Plaintiffs have met their
burden of admissibility under Daubert and D.R.E. 702.'°° The methodologies
underlying his opinions are scientifically valid as supported by his review of the
epidemiological studies. Plaintiffs have also met their burden for the admissibility
of Dr. Weisenburger’s other opinions, including his Bradford-Hill analysis in light
'33 Dr, Weisenburger Report at 6.
134 Td. at 6-10.
135 Td at 7.
136 Td. at 8-10.
37 Daubert Hearing Tr. at 207:15-208:2.
38 Td. at 208:11-17.
' See In re Roundup Litig., 2018 WL 2268534, at *28 (determining that Dr. Weisenburger’s
epidemiology opinion was admissible under Daubert).
28
of his interpretation of the underlying epidemiology studies.'*°
Dr. Weisenburger is qualified to render these opinions. His opinion will help
the trier of fact understand the evidence and determine the issue of general causation.
His testimony is based on sufficient facts and data, results from reliable principles
and methodologies, and he has reliably applied the principles and methodologies to
this case.!*!
C. Dr. Portier
Dr. Portier earned a Master’s degree and Ph.D. in biostatistics from University
of North Carolina.'42 His thesis dealt with the design of a “rodent carcinogenicity
study to assess the ability of a chemical to cause cancer....”!*? He is a biostatistician
who worked a large portion of his career at the National Institute of Environmental
Health Sciences and the National Toxicology Program and became the Director of
the National Center for Environmental Health in 2010.!4*
His subspecialty involves
environmental laboratory studies.'4° During his career, he has contributed to risk
assessments for [ARC.!*6
140 See In re Roundup Litig., 2018 WL 2268534, at *29 (holding that the remainder of Dr.
Weisenburger’s opinion, including his Bradford-Hill analysis, was admissible).
'41 See D.R.E. 702.
142 Def.’s Ex. 7, Expert Report of Dr. Christopher J. Portier in Support of General Causation on
ieee of Plaintiffs at 1 [hereinafter Dr. Portier Report].
Id.
144 Td. at 1-3.
145 Daubert Hearing Tr. at 543:5-6.
146 See Dr. Portier Report at 3.
29
Dr. Portier opines to a reasonable degree of scientific certainty that glyphosate
probably causes NHL and that the probability is high.!4” In formulating his opinions,
Dr. Portier reviewed epidemiology, toxicology, and mechanisms-of-cancer
literature."“8 As to the epidemiology literature, he identified six case-control studies
that showed “similar modest increases of associations between glyphosate and
NHL.” He also reviewed the AHS Cohort. Dr. Portier “concluded that causality
is possible, but there’s still the possibility of bias, chance, and confounding in these
data.”!°° He does not believe that bias, chance, and confounding are strong enough
to explain the entire association.!>!
Dr. Portier provided his own analysis of the epidemiology evidence, and
reached a similar conclusion as the IARC.'? He reviewed numbers that were
adjusted for the use of other pesticides, including the IARC Monograph and a study
by Chang and Delzell (2016).'* He noted studies that were going to be excluded
from his evaluation of causation or would only be given little weight in his
evaluation.'** Among the six core studies that he identified,'® Dr. Portier concluded
'47 Daubert Hearing Tr. at 545:10-13.
148 See id. at 545:1-5.
'9 Td. at 545:18-20.
'50 Td. at 546:3-5.
151 Tq. at 546:8-13.
'52 Dr, Portier Report at 6-18.
'93 Td. at 14-15.
'54 Td. at 9, 13.
'°° Id. at 15. These studies included McDuffie et al. (2001), Hardell et al. (2002), De Roos et al.
(2003) and (2005), Eriksson et al. (2008), and Orsi et al. (2009).
30
that “[t]here is a strong association across the six core studies.”!°° When using the
most-fully-adjusted numbers, Dr. Portier explained that there was a “modest
increase” in NHL with exposure to glyphosate, but that when the six studies were
combined they demonstrated “a significant strength of association.”!°’
Dr. Portier opines the studies provide a strong association and then performs
his Bradford-Hill analysis. He finds, based on two case-control studies and one
cohort study, that the biological gradient criterion was supported by a moderate
degree.'58 Dr. Portier concluded that the temporal relationship criterion of the
Bradford-Hill evaluation is satisfied because exposure came before the onset of
cancer.'°? As to the specificity criterion, Dr. Portier concluded that there is little
support for this element of the analysis, but also found that it was not needed.'®
Dr. Portier found that the consistency criterion was satisfied and strong after
discussing the six core studies and the Chang and Delzell (2016) meta-analysis that
showed similar results to the other studies and lends support that the findings are
consistent.!©! He ultimately found that the strength of the observed association
criterion was demonstrated by a strong degree.'®
156 Dr. Portier Report at 19.
157 Td.
158 Td. at 74-75, 77.
159 Td. at 75, 77.
160 Id.
161 Dr, Portier Report at 17-18, 77.
162 Td at 77.
31
Dr. Portier additionally evaluated the biological plausibility criterion and
found that it showed “very strong” support for causation. In reaching this finding,
Dr. Portier evaluated animal carcinogenicity studies and summarized that glyphosate
causes cancer in mammals.’ He further analyzed mechanisms relating to
carcinogenicity, including genotoxicity in humans and non-human mammals studies
and studies relating to oxidative stress.’ In conclusion, Dr. Portier opined “[t]here
is strong support for biological plausibility in support of a causal association of
glyphosate and glyphosate formulations with NHL.”!® As to the evidence in human
experimentation criterion, Dr. Portier held there were no studies available.'*’ Lastly,
he explained that there were no studies available as to the analogy criterion and he
does not have a sufficient background to render an opinion in this area.'®
Monsanto argues that Dr. Portier is not qualified to render epidemiology-
based opinions because he is a toxicologist without the requisite specialized
knowledge or experience. This Court disagrees. The Court finds that Dr. Portier
is qualified to offer opinions regarding epidemiology even though he is not an
epidemiologist because he has reviewed epidemiology literature throughout his
163 Dr. Portier Report at 77.
164 Td. at 51-52.
165 Td. at 19-74.
166 Td at 73.
167 Td. at 76, 77.
'68 Dr. Portier Report at 76, 77.
169 Def.’s Opening Br. at 12, n.18.
32
career, !7
Dr. Portier’s epidemiology-related opinions and his Bradford-Hill analysis are
reliable under Daubert and are admissible. Dr. Portier employed sound
methodology when reviewing the epidemiology studies and conducting his analysis
of the Bradford-Hill criteria, with the exception of his pooling method. Dr. Portier
used a pooling method to analyze the results of multiple rodent carcinogenicity
studies. Monsanto argues that Dr. Portier’s pooling method is a “novel technique”
and he engaged in selective pooling to create statistically significant results.'! To
determine whether Dr. Portier’s pooling method is rooted in science, the Court looks
to the non-exhaustive factors provided by Daubert. First, there is no evidence that
this method has been tested. Next, his pooling method does not appear to have been
subject to peer review. Also, his method has not gained general acceptance in the
scientific community.!’? Because Dr. Portier’s pooling method is not derived from
the scientific method, it is not reliable under Daubert.'? Thus, Dr. Portier’s opinions
regarding animal carcinogenicity are admissible with the exception of the pooled
0 See D.R.E. 702 (providing that expert may be qualified based on skill, experience, or training).
'7l See Def.’s Opening Br. at 29-34.
172 Daubert Hearing Tr. 638:2-13. Dr. Portier testified that he might be the only one who has
performed this pooling analysis, suggesting that it is not generally accepted in the scientific
community. Dr. Portier contended that another scientist used a similar pooling method, but
Monsanto noted the differences in the pooling analysis in the other studies. See id. at 635:19-
636:16.
'3 See Bowen, 906 A.2d at 794 (citing Daubert I, 509 U.S. at 590).
33
analysis.'”* His mechanistic data opinions are admissible because the methodologies
relied upon to form his opinions are grounded in science.'7> Monsanto can utilize
cross-examination and presentation of contrary evidence to attack the evidence
presented through Dr. Portier.”
D. Dr. Jameson
Dr. Jameson received a Ph.D. in Organic Chemistry and has worked for the
National Institutes of Health’s National Cancer Institute (“NCI”) on the Rodent
Bioassay program and has contributed to hundreds of bioassay studies.'”’ He is an
environmental toxicologist and has served as a member of IARC working groups
throughout his career.!78
Before discussing the epidemiology evidence, Dr. Jameson summarized the
IARC Monograph and the working group’s evaluation.'!”? In addition to
summarizing the IARC Monograph, he outlined the criteria he used for his “hazard
based assessment of glyphosate and/or glyphosate-based formulations” and
explained that it “is the same as defined and characterized by IARC.”'®° His opinion
emphasized significant reliance on the IARC Monograph and his decision to perform
\4 See In re Roundup Litig., 2018 WL 3368534, at *24.
"5 See Tumlinson I, 2013 WL 7084888, at *2.
176 See Daubert I, 509 U.S. at 596.
'77 Pls.’ Ex. 8, Expert Report of Dr. Charles W. Jameson, Ph.D. in Support of General Causation
on Behalf of Plaintiffs at 1 [hereinafter Dr. Jameson Report].
\78 See id. at 1, 4.
179 See id. at 4-8.
180 Td. at 9.
34
a similar analysis. He then reviewed the scientific literature in this case, including
the case-control studies, cohort studies, and meta-analyses, before providing a
summary for the human data.'*' As to the human evidence, Dr. Jameson concluded
that there is “limited” evidence, as defined by IARC, for the carcinogenicity of
glyphosate. !*
Next, Dr. Jameson conducted a hazard assessment of the experimental animal
data for glyphosate formulations, reviewing cancer bioassays in mice and in rats.'®
In summary, he concludes that there is “sufficient” evidence that glyphosate causes
184 T astly, Dr. Jameson performed
different types of tumors in experimental animals.
a hazard assessment of the mechanistic data for glyphosate, concluding there is
strong evidence indicating that glyphosate is genotoxic and induces oxidative
stress. !85
Overall, Dr. Jameson concludes “to a reasonable degree of scientific
certainty that glyphosate and glyphosate-based formulations are probable human
carcinogens.”!® Further, he concludes “to a reasonable degree of scientific certainty
that glyphosate and glyphosate-based formulations cause NHL in humans.”'®’ Dr.
Jameson explained that although he relied upon the IARC Monograph, he provides
181 See Dr. Jameson Report at 12-19.
182 Td at 19,
83 Td. at 19-27.
84 Td. at 29.
'85 See id, at 30-31.
186 Tr, Jameson Report at 31-32.
87 Td. at 32.
35
his own opinion that is not the IARC’s opinion.'®* Dr. Jameson draws from the
TARC Monograph to reach his conclusion that glyphosate and GBHs cause NHL in
humans.!8?
Monsanto takes issue with Dr. Jameson’s opinions, focusing on his
concession that animal bioassay studies are used to determine if the chemical can
cause cancer in animals, not humans.'° Although animal bioassay studies focus on
animals, “[o]ther forms of evidence including toxicology, in vivo studies, in vitro
studies, animal studies, and case studies can be used together to show causation.”!9!
Although animal toxicology studies alone may be insufficient to establish general
causation, Dr. Jameson’s opinions about the animal toxicology studies are relevant
to the issue of general causation. Dr. Jameson’s opinions and conclusions in his
expert report meet the reliability requirement under Daubert. These opinions are
reliable because he utilized sound scientific methodologies in reaching his
conclusions and are therefore admissible.
E. Dr. Neugut
Dr. Neugut, M.D., Ph.D. is a practicing medical oncologist, a Professor of
Cancer Research and Professor of Medicine and Epidemiology at Columbia
188 Daubert Hearing Tr. 417:20-418:13.
189 Td. 418:22-419:4.
190 Def.’s Opening Br. at 22.
'91 Tymlinson I, 2013 WL 7084888, at *9.
36
University, and Associate Director for Population Sciences for the Herbert Irving
°2 His specialty is epidemiology. Dr. Neugut
Comprehensive Cancer Center.!
reviewed the relevant literature, and concluded that “epidemiologic and scientific
evidence currently available leads to the conclusion to a reasonable degree of
scientific certainty for most expert, objective, and reasonable viewers, myself
included, that the use of glyphosate in its various combinations can cause non-
Hodgkin lymphoma.”!” As to the epidemiology evidence, there is no dispute that
Dr. Neugut is qualified to render these opinions.'* The issue is whether his opinions
satisfy the reliability prong of the Daubert standard.
Dr. Neugut’s report reviewed various epidemiology studies that were broken
up by cohort studies, case-control studies, and meta-analyses and discussed their
results.!° The report next reviewed toxicity studies, looking at animal studies and
studies in human cells in vitro.'*
After this review, Dr. Neugut analyzed the
Bradford Hill criteria for causation and addressed each factor and whether the factors
weigh in favor that the association of glyphosate exposure and NHL is causal.'?’
The MDL Court explained there were significant inconsistencies between the
192 Dis,” Ex. 6, Expert Report of Dr. Alfred I. Neugut, MD, PhD in Support of General Causation
on Behalf of Plaintiffs at 2 [hereinafter Dr. Neugut Report].
3 Td. at 23.
194 See Def.’s Opening Br. Monsanto argues that Dr. Neugut is not qualified to render opinions
on rodent bioassay data or mechanistic data. See id. at 22, n.42 and 42, n.71.
195 Dr, Neugut Report at 11-17.
196 Td. at 17-20.
'97 Td. at 20-22.
37
testimony he offered at his deposition and at the Daubert hearing.'°8 According to
the MDL Court, the problems with Dr. Neugut’s testimony “were far more apparent
in the courtroom” than how they are reflected in the written transcript.!”? Although
Dr. Neugut is qualified to testify about the epidemiology evidence, his misstatements
during his testimony cast into doubt the reliability of his opinions. Similar to the
MDL Court, this Court finds that given the inconsistencies in Dr. Neugut’s
testimony, his opinions do not satisfy the Daubert standard for reliability.?°°
Plaintiffs failed to demonstrate by a preponderance of the evidence that Dr. Neugut’s
opinions are reliable. Therefore, Dr. Neugut’s opinions are inadmissible under
D.R.E. 702 and Daubert.
F. Dr. Nabhan
Dr. Nabhan is a hematologist and medical oncologist “with a specialty in the
diagnosis and management of patients with all types of lymphoma, including non-
Hodgkin (NHL).””°! During the Daubert hearing, Dr. Nabhan reiterated that he was
not an epidemiologist.” He is a clinician, who has incorporated epidemiology and
'8 See In re Roundup Litig., 2018 WL 3368534, at *30 “However, Dr. Neugut’s testimony at the
Daubert hearing was of a much lower quality.”).
199 Id. (identifying problems with Dr. Neugut’s testimony).
200 See id, at *30-31 (identifying a few examples of the problems with Dr. Neugut’s testimony that
undermined its reliability).
20! Pls.’ Ex. 8, Expert Report of Dr. Nabhan in Support of General Causation on Behalf of Plaintiffs
at 1 [hereinafter Dr. Nabhan Report].
202 Daubert Hearing Tr. at 805:1-4, 818:24-819:3.
38
toxicology into his work and studies.” Dr. Nabhan testified that he relied heavily
on the IARC in formulating his opinion.”™
His report looked at mechanistic and animal studies of glyphosate, finding
that based on animal data there is “carcinogenic potential for glyphosate.” Dr.
Nabhan assessed epidemiological studies to examine the carcinogenic risk of
glyphosate in humans.” Next, he considered meta-analyses on the associations
between glyphosate and NHL.” He also examined systematic reviews, including
the IARC Monograph.” Lastly, Dr. Nabhan conducted an analysis of the Bradford-
Hill criteria.2°? He concludes that the “weight of the scientific evidence supports
causality between Roundup/glyphosate exposure and NHL.”?!°
It is not necessary to require a medical doctor to be an epidemiologist in order
to testify about epidemiological studies,”’’ and this Court agrees that Dr. Nabhan
does not have to be an epidemiologist to render his opinion about epidemiological
studies. The problem with Dr. Nabhan’s opinion is that he relies heavily and
203 Dr. Nabhan Report at 3-4.
204 Daubert Hearing Tr. at 844:16-18.
205 Dr. Nabhan Report at 8.
208 Td. at 11-15.
207 Td. at 15-16.
208 Td. at 16-18.
209 Td. at 19-21.
210 Dr. Nabhan Report at 22.
211 See In re Roundup Litig., 2018 WL 3368534, at *33; In re Mirena IUD Products Liability
Litigation, 169 F. Supp. 3d 396, 426 (S.D.N.Y. 2016) (“Moreover, medical doctors do not need to
be epidemiologists in order to testify regarding epidemiological studies.”).
39
uncritically on IARC’s conclusions. At the Daubert hearing, Dr. Nabhan
demonstrated a strong reliance on IARC and its conclusions regarding glyphosate
exposure and NHL.”!* The IARC alone does not suffice. Unlike other experts, Dr.
Nabhan has not employed appropriate methodologies to reach reliable conclusions
regarding that glyphosate can cause NHL for purposes of general causation.?!3 The
Court finds that Plaintiffs fail to establish the reliability of Dr. Nabhan’s opinions
under Daubert; thus, Dr. Nabhan’s opinions are inadmissible under D.R.E. 702.
In sum, Plaintiffs have met their burden by a preponderance of the evidence
that the expert opinions of Drs. Ritz, Weisenburger, Portier, and Jameson are
admissible. Plaintiffs’ have failed to meet their burden as to Drs. Neugut and
Nabhan. Therefore, Defendant Monsanto Company’s Daubert Motion is
GRANTED, in part, and DENIED, in part, as outlined.
V. MONSANTO’S MOTION FOR SUMMARY JUDGMENT
A. Motion for Summary Judgment Standard
Delaware Superior Court Civil Rule 56 mandates the granting of summary
judgment where the moving party demonstrates that “there is no genuine issues as
to any material fact and that the moving party is entitled to judgment as a matter of
212 See In re Roundup Litig., 2018 WL 3368534, at *33-34; Daubert Hearing Tr. at 850:7-21
(discussing that the IARC report is “very convincing”).
213 See In re Roundup Litig., 2018 WL 3368534, at *32-33 (holding that Monsanto’s motion to
exclude Dr. Nabhan’s testimony was granted because he did not provide “a reliable basis for
concluding that glyphosate can cause NHL as a general matter”).
40
law.”2!4 If the moving party satisfies its initial burden, the non-moving party must
sufficiently establish the “existence of one or more genuine issues of material
fact.”2!5 Summary judgment will not be granted if there is a material fact in dispute
or if “it seems desirable to inquire thoroughly into [the facts] in order to clarify the
application of the law to the circumstances.””!° “All facts and reasonable inferences
must be considered in a light most favorable to the non-moving party.”?
B. Monsanto’s Motion for Summary Judgment Analysis
Monsanto argues that it is entitled to summary judgment because Plaintiffs
failed to present admissible expert testimony under Daubert to prove general
causation.
Toxic tort cases, such as here, require the plaintiffs to prove general causation.
This must be satisfied by presenting expert testimony because the issue of general
causation is outside the knowledge of lay jurors. If plaintiffs do not provide proof of
general causation, then they are unable to establish an essential element of their case
and summary judgment should be granted in favor of the defendant. Because
Plaintiffs have provided expert opinions that are admissible under Daubert to prove
214 Super. Ct. Civ. R. 56(c).
215 Quality Elec. Co., Inc. v. E. States Const. Serv., Inc., 663 A.2d 488, 1995 WL 379125, at *3-4
(Del. 1995). See also Rule 56(e); Moore v. Sizemore, 405 A.2d 679, 681 (Del. 1979).
216 Ebersole v. Lowengrub, 180 A.2d 467, 469-70 (Del. 1962).
217 Nutt v. A.C. & S. Co., Inc., 517 A.2d 690, 692 (Del. Super. 1986) (citing Mechell v. Palmer,
343 A.2d 620, 621 (Del. 1975); Allstate Auto Leasing Co. v. Caldwell, 394 A.2d 748, 752 (Del.
Super. 1978)).
41
general causation, Monsanto is not entitled to summary judgment.
VI. PLAINTIFF’S DAUBERT MOTION TO STRIKE
Plaintiffs also seek to exclude certain opinions of four of Monsanto’s experts,
including Drs. Goodman, Foster, Rider, and Mucci. They argue that these experts’
opinions fail to meet the Daubert standard because they are based on unsound
methodologies and are unreliable.
A. Dr. Goodman
Dr. Goodman is a Professor in the Department of Pharmacology and
Toxicology at Michigan State University and is board certified in toxicology.?!® Dr.
Goodman reviewed scientific literature regarding glyphosate and its potential
genotoxicity, and concluded that GBFs, glyphosate and AMPA “should be regarded
as non-genotoxic materials.”!°
Plaintiffs contend that Dr. Goodman’s opinions are inadmissible because he
discounted two human in vivo studies and his opinions are based on results-driven
methodology.””° Similar arguments were raised in the MDL case and that Court
found that his method and analysis were not so flawed as to require exclusion, and
therefore his opinions were admissible.22!
*18 Pls.’ Ex. 82, Glyphosate: Review and Interpretation of Key Aspects of the Scientific Literature
Concerning Genotoxicity and Oxidative Stress Data by Jay I. Goodman at 1 [hereinafter Dr.
Goodman Report].
219 Td. at 3.
220 Bis,” Answering Br. at 63-70.
221 See Inre Roundup Litig., 2018 WL 3368534, at *34.
42
This Court agrees with the well-reasoned finding of the MDL Court.” The
methodology utilized by Dr. Goodman meets the Daubert reliability requirement
because it has been tested, published, peer-reviewed, and is generally accepted in
the scientific community.”7? Monsanto has met its burden that Dr. Goodman’s
testimony is admissible.
B. _ Dr. Foster
Dr. Foster is a toxicologist who engages in research and conducts animal
studies in the field.22* He concluded, upon review of animal studies, that “within a
reasonable degree of scientific certainty, glyphosate is not a rodent carcinogen.”””°
Dr. Foster is qualified to offer his opinions based on his experience and training in
toxicology. Plaintiffs seek to exclude his opinions arguing that they are not based
on sound methodology.” Plaintiffs raise issues with Dr. Foster’s method of
comparing what are known as the Lankas study and the Atkinson and Suresh
studies.?’
Similar to Plaintiffs experts, Dr. Foster reviewed the relevant literature and
222 See In re Roundup Litig., 2018 WL 3368534, at *34 (“Although he reaches different
conclusions about what the weight of the mechanistic evidence shows, his analysis is not so flawed
or one-sided that his opinions need be excluded.”).
223 See Tumlinson I, 2013 WL 7084888, at *2 (citing Daubert I, 509 U.S. at 593-94).
224 Dis.’ Ex. 65, Expert Witness Report of Warren G. Foster, Ph.D. FCAHS at 3 [hereinafter Dr.
Foster Report].
225 Id. at 29.
226 Dis.’ Answering Br. at 70-74.
227 See id. at 70-72. Plaintiffs also raise concern that the Atkinson and Suresh studies do not
examine all of the treated animals. Jd. at 72.
43
evaluated the various studies. Although Dr. Foster had a different interpretation of
the same studies relied upon by Plaintiffs, this does not render his opinions
inadmissible.?28
Dr. Foster’s opinions are scientifically reliable because his
methodology is rooted in science.*”? Monsanto has demonstrated that Dr. Foster’s
opinions are reliable under Daubert, and therefore are admissible under D.R.E. 702.
C. Drs. Rider and Mucei
As to Drs. Rider and Mucci, Plaintiffs requested at oral argument that if they
are going to testify at trial that their testimony be limited to epidemiology. Plaintiffs
move to strike both of these doctors’ opinions because they did not use reliable
methodology.” Both experts reviewed the relevant epidemiology studies, like the
other experts, and reached their own conclusions. Dr. Rider concluded that “the
epidemiologic evidence does not provide a basis sufficient to opine that glyphosate-
based herbicides are causally related to NHL.”*3! Dr. Mucci opines “to a reasonable
degree of scientific certainty, that the epidemiological evidence does not provide a
scientific basis to support a causal relationship between exposure to glyphosate-
based herbicides and the risk of NHL.”222
8 See In re Asbestos Litig., 911 A.2d at 1201 (“When a trial court determines that an expert’s
testimony is reliable, this does not mean that contradictory expert testimony by default is
unreliable.”).
229 See Bowen, 906 A.2d at 794 (citing Daubert I, 509 U.S. at 590).
230 Pls.” Answering Br. at 74.
31 Pls.’ Ex. 93, Expert Report of Jennifer R. Rider, ScD at 47 [hereinafter Dr. Rider Report].
232 Pls.’ Ex. 94, Expert Report of Lorelei A. Mucci, ScD, MPH at 71 [hereinafter Dr. Mucci
Report].
44
Drs. Rider and Mucci provide opinions on epidemiology, and they utilized
reliable methods to reach their conclusions about the epidemiology evidence. Drs.
Rider and Mucci used sufficiently reliable methods under Daubert to reach their
respective conclusions on the epidemiological evidence, and their opinions will be
limited to that evidence.
Monsanto has established the admissibility of their experts’ opinions by a
preponderance of the evidence. Therefore, Plaintiff's Daubert Motion to Strike
Certain Opinions of Defendant’s Expert Witnesses is DENIED.
VII. CONCLUSION
For the reasons stated above, Monsanto’s Daubert Motion is GRANTED, in
part, and DENIED, in part, and its Motion for Summary Judgment is DENIED.
Plaintiffs’ Daubert Motion to Strike Certain Opinions of Defendant’s Expert
Witnesses is DENIED.
IT IS SO ORDERED.
43 udgé Vivian L. Medinjiis
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