By Jacob Bunge and Sara Randazzo

The California Supreme Court declined to hear an appeal by Bayer AG seeking to reverse a jury verdict that the company's Roundup herbicide caused a groundskeeper's cancer, leaving the company with few remaining options to avoid paying a $20.4 million judgment.

The German drug and agriculture conglomerate had challenged a 2018 verdict in California state court that found the company's Roundup products posed a danger to users like plaintiff Dewayne "Lee" Johnson, and that the company failed to warn consumers of potential health risks. It was the first of three jury decisions in favor of Roundup-using plaintiffs, helping build a wave of lawsuits and eventually leading Bayer to strike a $10.9 billion settlement deal with tens of thousands of plaintiffs in July.

Bayer didn't admit to any wrongdoing as part of the July settlement and will continue to sell Roundup. The herbicide is the world's most widely used, sprayed on residential gardens and on tens of millions of acres of crops genetically engineered to withstand it.

Bayer acquired Monsanto, Roundup's maker, in a $63 billion deal that closed weeks before the jury ruled in favor of Mr. Johnson, a former school groundskeeper. The company has maintained that Roundup is safe, citing regulatory reviews by the U.S. Environmental Protection Agency and other authorities.

The company has said it would continue to challenge the three jury verdicts as it implements the broader settlement. On Friday, a federal appeals court will hear arguments in Bayer's challenge to a jury verdict in favor of Edwin Hardeman, a Northern California resident who claimed his yearslong Roundup use led to his non-Hodgkin lymphoma.

In July, a California appeals court ruled against Bayer's appeal in the Johnson case, though damages were reduced to $20.4 million from an already reduced $78.5 million. In denying to review that decision Thursday, the California Supreme Court didn't weigh in on the merits of the case. California's highest court accepts only a fraction of appellate requests.

"The time has come for Monsanto to end its baseless appeals and pay Mr. Johnson the money it owes him," said a spokesman for the Miller Firm, which represented Mr. Johnson in the case.

A Bayer spokesman said the company was disappointed the California court didn't take up the appeal and was considering its legal options.

The company could try to appeal the case to the U.S. Supreme Court, but only if a question of federal law is at stake.

Write to Jacob Bunge at jacob.bunge@wsj.com and Sara Randazzo at sara.randazzo@wsj.com

(END) Dow Jones Newswires

10-22-20 1404ET