SAN FRANCISCO (CN) - Attorneys for a California man claiming Monsanto's Roundup weed killer gave him lymphoma and a prominent oncologist testifying on the agrochemical company's behalf sparred in a San Francisco courtroom Monday over the seemingly murky causes of the disease, on the last full day of trial testimony before a federal jury decides if the popular herbicide is carcinogenic.
Plaintiff Edwin Hardeman alleges he developed non-Hodgkin lymphoma from using Roundup for nearly three decades on his sprawling Northern California property. But on Monday, City of Hope hematologist and oncologist Alexandra Levine testified that Hepatitis C was the likely culprit behind Hardeman's illness.
An expert in lymphoma and Hodgkin's disease at City of Hope, a cancer treatment center in Duarte outside Los Angeles, Levine explained to the six-person jury that cancer is caused by "an accident or error," called a mutation, in a cell's DNA, and that Hepatitis C can cause such accidents or errors. Hardeman's medical records indicate he had an active Hepatitis C infection for 39 years, Levine said, "allowing a real opportunity for an accident to occur."
Hepatitis C "is unusual and different in the sense that it has the ability to get into our DNA and cause all kinds of accidents," she said. "It can cause accidents all over the place in our DNA. It's a very different virus."
Hardeman's attorneys have sought throughout the two-week trial to discredit the idea that Hepatitis C caused Hardeman's diffuse large B-Cell lymphoma, a type of non-Hodgkin lymphoma. They point out that his treating physicians at Kaiser Permanente in 2005 declared him cured of Hepatitis C after undergoing antiviral therapy, and that he didn't test positive for Hepatitis B - to which he had been exposed and developed antibodies but not a full-blown infection - during six rounds of chemotherapy in 2015.
They contend that if inactive Hepatitis B cells had remained in Hardeman's body, he would have tested positive for the virus during chemotherapy, when his immune system would have been too weak to fight off a reactivated infection.
But Levine said Monday that curing hepatitis doesn't cure the mutations it leaves behind that can grow into cancer.
"The presence or absence of Hepatitis C in the body wouldn't matter once the accident was there," Levine said, later adding that this mechanism by which the virus enters a cell, produces mutations, then exits the cell following treatment, is known in research circles as a "hit-and-run."
"The accident is there; it doesn't need the Hepatitis C anymore," she said.
Researchers have yet to prove that a hit-and-run mechanism also operates for Hepatitis B, but "theoretically," it should, Levine said. Based on this, she said, Hardeman's Hepatitis B was also a likely driver of his non-Hodgkin lymphoma.
Plaintiff's attorney Jennifer Moore assailed Levine's conclusion.
"What is your evidence that there are hit-and-run cells for Hepatitis B?" Moore asked her on cross-examination.
"The hit-and-run mechanism has not been published for Hepatitis B," Levine replied.
"So you don't have any evidence that Hepatitis B is a hit-and-run?" Moore asked.
"I can't say that; for Hepatitis C, certainly," Levine answered.
Later, to support her conclusions about the causes of Hardeman's illness, Levine pointed to studies showing that patients with antibodies to Hepatitis B have an increased risk for developing diffuse Large B-Cell lymphoma.
"What's your evidence to support that theory?" Moore likewise asked.
The exchange highlighting Levine's apparent dearth of evidence about Hardeman appeared to damage her credibility to the jury. But during a recess outside the jury's presence, Monsanto attorney Brian Stekloff, of Wilkinson Walsh Eskovitz, said Moore's last question had "opened the door" to letting Levine testify about BCL6 - a mutation associated with Hepatitis C that was observed in Hardeman's tumor pathology.
Presiding U.S. District Judge Vince Chhabria denied Monsanto's two previous requests to admit evidence regarding BCL6 after the company's attorneys failed to disclose it before trial. But the judge relented Monday, adding that the testimony would allow Levine to "clear up the impression about the lack of evidence she has" about Hardeman's illness.
On redirect, Levine testified that there is an association between Hepatitis C and the BCL6 mutation, that Hardeman tested positive for the mutation and that antiviral therapy would not cure the mutation.
"He had an active infection for 39 years and it could easily have mutated during those 39 years, and once that mutation is there, it did not matter if he had live virus in the blood," Levine said. "It did not matter."
Closing arguments in the first phase of the trial are set for Tuesday. If the jury finds that Roundup caused Hardeman's cancer, trial will proceed on Wednesday to a second phase to determine Monsanto's liability and damages.
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