SAN FRANCISCO (Legal Newsline) - Bayer AG has asked the judge overseeing multidistrict litigation over Roundup herbicide to disqualify several plaintiff experts who consistently blame non-Hodgkin's lymphoma on Roundup when being paid to testify in court, despite numerous other risk factors that could have triggered the disease.
Two of the experts are oncologists who have acknowledged they have never told a patient in their clinical practice that they contracted the cancer from exposure to Roundup.
“While quick to rule in Roundup in every case, these experts refuse to also rule in known NHL risk factors,” Bayer’s Monsanto unit complains in a filing with U.S. District Judge Vince Chhabria in California. Judge Chhabria previously allowed plaintiff experts to testify that Roundup causes cancer, despite the U.S. government’s position that it does not, saying their evidence “barely inched over the line.”
Bayer is facing an eruption of litigation after plaintiffs won multimillion-dollar verdicts in state and federal court, which prompted plaintiff lawyers to advertise heavily for 100,000 more clients who claim they got non-Hodgkin's lymphoma from using Roundup. It moved to disqualify the experts before a series of bellwether trials scheduled to test plaintiff theories even though the company has offered some $11 billion to settle most of the existing cases against it.
The active ingredient in Roundup, glyphosate, is one of the most commonly used industrial chemicals and non-Hodgkin's lymphoma is a common cancer that occurs more frequently as people age, so the number of claims can only be expected to increase unless Monsanto can break the evidentiary chain between Roundup and cancer. The U.S. Environmental Protection Agency says glyphosate is safe, as do most other national regulators, and Monsanto is prohibited by law from placing a cancer warning on the product.
Plaintiff experts rely mostly on a 2015 finding by the World Health Organization’s International Agency for Research on Cancer that glyphosate is a probable carcinogen. Chris Portier, now a plaintiff expert himself, was non-voting chairman of the committee that made the finding despite strong epidemiological evidence involving tens of thousands of agricultural workers that glyphosate doesn’t cause abnormal rates of cancer.
Armed with the IARC finding, medical experts then can offer their opinion to the jury that glyphosate caused a specific plaintiff’s cancer. They describe the process as “differential etiology,” a variation on differential diagnosis, the standard process by which doctors determine a disease by ruling in or out explanations for the patient’s symptoms.
With “differential etiology,” plaintiff experts use a similar reasoning process to rule in or rule out the cause of a disease in order to meet the civil legal threshold of more probable than not. Few physicians would claim to use differential etiology in their practice, however, since the exact cause of a disease can rarely be known with certainty.
“The differential `etiology’ is a `legal construct’ that is not used in actual medical practice and has no support in published medical literature,” Bayer said, describing it as “courtroom advocacy in a lab coat.”
The company sought to disqualify Dr. Barry Boyd, Dr. Lauren Pinter-Brown and Dr. Ron Schiff, all oncologists. Bayer says Drs. Boyd and Schiff consistently attributed NHL to Roundup in the plaintiff files they examine, despite numerous risk factors more closely associated with the disease include age and other cancers.
Dr. Pinter-Brown also consistently blames Roundup while acknowledging most cases of NHL have no known cause, undercutting her opinion it was more likely than not the cause of disease in the cases she has been hired to review. Dr. Schiff has testified that 80% of patients he treated with NHL did not have a known cause for the disease and he never told any patients glyphosate caused their cancer until after he retired from the practice of medicine and became a full-time plaintiff expert. In a deposition, the doctor said he came to recognize the risks of glyphosate after reading the 2015 IARC report.
“Dr. Schiff’s inability to offer any rational explanation for the striking contrast between his testimony that eighty percent of the patients he treated had no known cause for their NHL and his conclusion that Roundup was the cause of every Plaintiffs’ NHL thus far—apart from the obvious outcome-driven one—renders his testimony unreliable and inadmissible,” Bayer argues.
The company also listed several plaintiffs with known risk factors for NHL and other cancers who seek money because they used Roundup. One man claims he was exposed to glyphosate operating a lawn-care business but has a family history of cancer, including a mother who died of NHL, and he previously blamed his NHL on exposure to chemicals in his drinking water in an unrelated class action. Another plaintiff was a pack-a-day smoker for 43 years with a strong family history of cancer.
“The bottom line for these witnesses is that Roundup will always be the cause of every plaintiff’s NHL as long as the plaintiff was exposed to some amount of Roundup at some point in their life—regardless of the plaintiff’s individual medical history and risk factors,” Monsanto said. It is still seeking to disqualify experts who testified in previous trials and called these newly identified experts as “nakedly outcome-driven.”