SAN FRANCISCO (Legal Newsline) - Experts once called "shaky" by the federal judge hearing thousands of Roundup cases can continue to testify, as the latest wave of plaintiffs make their way through a multidistrict litigation proceeding.
The methods of many researchers were up for debate in the MDL, overseen by San Francisco judge Vince Chhabria. Monsanto, now under the ownership of Bayer, last year hoped recent changes to evidence standards would result in a group of plaintiff experts being unable to testify.
It was in August that Monsanto began seeking to disqualify experts once deemed admissible by Chhabria. They are general-causation experts whose opinions apply to all cases.
Monsanto was pointing at Rule 702 and its recent amendment to Federal Rules of Evidence targeting so-called "junk science." It went into effect in 2023, and though Bayer says it has a winning record in the many trials that have gone on around the country, losses result in eye-popping verdicts.
One Philadelphia jury awarded $2.25 billion, later reduced to $400 million while Bayer appeals. In 2018 in the San Francisco MDL, Chhabria wrote there were "significant problems" with plaintiffs' general-causation experts, and that their admissibility was "a very close question."
Chhabria pointed at three cases as reasons for ultimately allowing the testimony, but Rule 702 should have prodded him the other way, Monsanto said.
"Indeed, the amendments directly implicate the Court's (2018) analysis..." Monsanto wrote. "For example, the Court recognized that the opinion of one of Plaintiffs' experts, Dr. (Christopher) Portier, was 'far from unassailable' given the 'legitimate concerns about the reliability of the data' that he relied on
"Despite this, the Court deemed his opinion admissible, stating that Monsanto could 'cross-examine Dr. Portier on the apparent weaknesses in his analysis, and there is little reason to think that a jury will not understand those weaknesses.'"
Chhabria, though, said in September his previous rulings did not need to be reconsidered, no matter the new standards of Rule 702.
"Those rulings will continue to serve as the guideposts for decision in future motions to exclude general causation or specific causation experts," he wrote.
Among the experts Monsanto wanted excluded were Portier, saying his opinion can only be presented if Portier demonstrates his testimony is based on sufficient facts, is the product of reliable principles and methods and reflects a reliable application of the principles and methods to the facts of the case.
Portier was the chairman on the International Agency for Research on Cancer, which kickstarted litigation in 2015 when it became the only group to find glyphosate, the active ingredient in Roundup, is a probable carcinogen.
He left the IARC to work as an expert for plaintiff lawyers. Last year, Chhabria tossed a "meta-analysis" published in 2019 by toxicology professor Dr. Luoping Zhang because it cherry-picked data to come to the conclusion Roundup causes Non-Hodgkins lymphoma.
Portier and three others were criticized by Monsanto as being similarly out-of-touch in not recognizing research that has been published since 2019 - "These experts have no disclosed new expert reports in years."
"Rather than provide reports from these experts that take the latest science into consideration, Plaintiffs' Wave VII Rule 26 disclosures have simply incorporated by reference these experts' prior reports," Monsanto added. "But such outdated reports cannot be reliable, as this Court has held."
And other experts continue to rely on the since-tossed analysis of Zhang, Monsanto said. One such person is Dr. Kristan Aronson, who in 2023 was involved in a St. Louis case when it was discovered she only formed an opinion when approached by plaintiffs lawyers with the IARC study.
The judge hearing the case granted a directed verdict to Monsanto. A separate motion to exclude her testimony in the San Francisco MDL feared, among other things, she would compare Bayer and Monsanto to the tobacco, lead or asbestos industries.
"(T)his testimony would be unfairly prejudicial: this opinion is simply an attempt to score points with the jury by [incorrectly] painting Monsanto as a general bad actor who exerted undue influence on its own regulators," Monsanto wrote.
There are more than 4,400 cases in the MDL, even after Monsanto settled 100,000 others for about $11 billion. There are probably 50,000 more Roundup cases in state courts, the company says.
Late last year, the Federal Court of Australia closed all Roundup cases after a court found the weight of scientific evidence did not support a link between glyphosate and NHL. It was the first final Roundup judgment outside of the U.S. on that issue.
Bayer, as of Jan. 3, had won 15 of the last 22 trials. The cases of plaintiffs in Wave VIII of the litigation are proceeding, leading to a new round of expert disqualification issues being preserved for possible appeals.
Chhabria did exclude some testimony, including from Zhang, from other Wave VII experts after declaring his previous decisions would guide his future ones. He told the sides on Jan. 14 that when preparing their new disqualification motions for Wave VIII, "they should carefully review the Court's recent Wave 7 orders."
"If a party is considering filing a motion that covers an issue addressed in a previous order, they should clearly note in their motion that the issue is being raised for preservation purposes only," he added.
On Feb. 10, motions to exclude the general causation experts, including Portier, were denied again, as they were filed for preservation purposes only.