A US judge has confirmed a previous cancer ruling against Bayer AG unit Monsanto over its Roundup herbicide, drivingthe German chemical company’s shares down 7%, reports Reuters.

In a ruling on 22 October, San Francisco Superior Court of California judge Suzanne Bolanos said she would slash the damages awarded to ex-groundskeeper Dewayne Johnson to US$39M from the US$289M initially awarded in August.

Bayer, which completed its US$63bn acquisition of Monsanto in June, said that the decision to reduce the damages was a step in the right direction, but it would still file an appeal with the California Court of Appeal, because the verdict was not supported by the evidence presented at the trial, Reuters said.

On 10 August, a jury in California found that Monsanto’s glyphosate-based weed-killers, including RoundUp and Ranger Pro, had caused Johnson’s cancer and that the company failed to warn consumers about the risks.

Monsanto, which denies the allegations, had asked the Bolanos to set aside the entire original US$289M verdict or order a new trial on the punitive damages portion, Reuters said.

Bolanos then issued a tentative ruling on 10 October saying she was considering ordering a new trial on punitive damages, saying Johnson had failed to meet his burden of producing clear and convincing evidence of malice or oppression by Monsanto, a requirement for allowing a jury to award punitive damages.

Following that tentative ruling, at least five of the jurors who delivered the 10 August verdict sent letters to the judge, urging her to uphold their decision.

Johnson’s case was the first to go on trial over allegations of glyphosate causing cancer but Bayer is facing more than 8,700 similar cases from plaintiffs in the USA, with cases set to start in February. Investors fear a wave of costly ligitation against Monsanto, the US seed and pesticide giant that also produces GM seeds such as soyabeans and corn.

Lawyers for Johnson said they were still reviewing whether to accept the reduced award or retry the punitive damages portion.

Reuters wrote that if Johnson accepted the reduced damages, the final verdict would order Monsanto to pay a total of US$78M, split equally between compensatory and punitive damages. Bolanos said California’s constitution did not permit a higher amount of punitive damages.

Bayer said decades of scientific studies and real-world use had shown glyphosate to be safe for human use.

The US Environmental Protection Agency found in 2017 that glyphosate was not likely to cause cancer in humans, contradicting a 2015 World Health Organization report that classified glyphosate as “probably carcinogenic to humans.”

Johnson’s case, filed in 2016, was fast-tracked for trial due to the severity of his non-Hodgkin’s lymphoma, a cancer of the lymph system that he alleged was caused by years of glyphosate exposure, Reuters wrote.