SAN FRANCISCO (CN) – In a bid to discredit a Columbia University cancer expert who says Monsanto’s Roundup weed killer is carcinogenic, lawyers for the agrichemical giant accused him on Wednesday of lying under oath about the purported link between Roundup and cancer, in a contentious California jury trial over whether the weed killer caused a Bay Area man’s deadly lymphoma.
Several times on cross-examination, Alfred Neugut, a professor of medical oncology and cancer epidemiology, answered questions posed to him on the stand differently than he had in depositions taken in 2017 and 2018. The discrepancies prompted Monsanto attorney George Lombardi to imply that Neugut was lying, and agitated retorts from Neugut, including yelling at Lombardi to stop “misquoting” him.
“Did you get asked that question under oath and give a different answer?” the Winston & Strawn attorney repeatedly asked Neugut before a 16-person jury in San Francisco County Superior Court.
Although U.S. and European regulators have concluded that glyphosate, the active ingredient in Roundup, is safe, the World Health Organization’s International Agency for Research on Cancer (IARC) classified it in 2015 as a probable human carcinogen, prompting a wave of lawsuits against Monsanto in the U.S., including plaintiff DeWayne Johnson’s.
Johnson sued in 2016 after he was diagnosed with a cutaneous form of non-Hodgkin lymphoma called mycosis fungoides that caused cancerous lesions to develop over most of his body. He says he developed symptoms after he was twice drenched in Roundup while spraying it in schoolyards for his job as a groundskeeper for the school district in Benicia, 40 miles east of San Francisco.
He also claims Monsanto has known for decades that Roundup is carcinogenic but didn’t disclose it for fear of disrupting its $6.6 billion global business.
Glyphosate is the most widely used agrichemical in history. Monsanto introduced it in 1974, and its use exploded in 1996 after Monsanto began selling “Roundup-ready” seeds engineered to resist the weed killer. More than 2.6 billion pounds of the chemical was spread on U.S. farmlands and yards between 1992 and 2012, according to the U.S. Geological Survey.
Monsanto earns $1.9 billion a year from Roundup and $10.2 billion from “seeds and genomics,” most of that category being Roundup-ready seeds.
Neugut is one of several experts who have concluded along with IARC that glyphosate causes non-Hodgkin lymphoma. But Monsanto points out regulators have repeatedly said glyphosate is not a human carcinogen, and has sought throughout the trial to discredit experts who side with IARC.
Monsanto’s Lombardi used the same strategy Wednesday, revealing that Neugut has a consulting contract for a different case with the Miller Firm – the law firm representing Johnson – and that he concluded glyphosate causes non-Hodgkin lymphoma without reviewing all of the epidemiological studies on glyphosate exposure.
More crucial to Lombardi’s strategy, however, was noting that six of Neugut’s answers Wednesday differed from those given in his deposition, presumably to boost Johnson’s chances of winning the case.
One of the questions involved the statistical significance of data: “You would not label an [glyphosate] exposure as being associated with an outcome unless there was a finding of increased [cancer] risk that it is statistically significant?” Lombardi asked.
“If we’re looking at a multiplicity of studies and [the exposures] are all positive…I’d say that statement is not necessarily accurate,” Neugut replied, adding, “The concept of statistical significance is becoming more flexible.”
But in an August 2017 deposition, Neugut replied “that’s correct” to the same question, according to Lombardi.
Neugut explained that his August 2017 answer pertained to a single study. For multiple studies, he said Wednesday, “that would not be my feeling.”
Earlier in the day, Neugut also testified about a 2018 update to the ongoing Agricultural Health Study, a cohort study published by the National Cancer Institute of more than 57,000 licensed pesticide applicators from Iowa and North Carolina.
Study participants were first surveyed between 1993 and 1997, and were asked about their use of 50 pesticides, including glyphosate. Sixty-three percent of participants completed a follow-up interview five years later about their pesticide use, and cancer outcomes were assessed.
The study reported no statistically significant association between glyphosate use and non-Hodgkin lymphoma.
Because 40 percent of the participants dropped out, however, researchers estimated their cancer outcomes using a statistical tool called imputation based on the answers of the 60 percent who responded.
According to Johnson’s lawyers, imputation biased the study to show no causal link between glyphosate exposure and non-Hodgkin lymphoma, and even that glyphosate exposure protects against the disease.
Neugut similarly criticized the Agricultural Health Study’s research methods, particularly the use of imputation given the fact that glyphosate use rose nearly tenfold after 1996. The increase in use rendered the data gathered before then “totally useless” for the purposes of imputation, he said.
Sensitivity analyses the study’s authors ran to check their imputation showed a 17 percent discrepancy, which, he said, caused the elevated cancer-risk ratio to disappear.
“You use imputation when you’ve got a screwed-up study with poor follow-up,” he said. “Unfortunately, this is a case of measuring s— with a gold scale, where it turns out the results just don’t turn out to be what they should be because there are so many problems.”
On redirect, Brent Wisner, an attorney with Baum, Hedlund Aristei & Goldman representing Johnson, said a nine-person study within the Agricultural Health Study found a statistically significant association between glyphosate exposure and T-cell lymphoma, the same type of cancer Johnson has.
But Lombardi countered that the study in question was a 20-year lag study, meaning it took 20 years for study participants to show symptoms of the disease.
In opening statements last week, Lombardi argued that Johnson’s lymphoma could not have been caused by glyphosate because he used Roundup for just two years before developing symptoms.
When Wisner asked if the study actually meant that it took 20 years to see the disease in the study, Neugut said he didn’t know. He instead cautioned against using the Agricultural Health Study to evaluate a potential link between glyphosate and cancer, calling the 20-year result a “throwaway.”
“We shouldn’t be using this study at all,” he said. “It has so many potential flaws.”
Testimony continues Friday.