US Judge Dean Ochiai has ordered Bristol-Myers Squibb (BMS) and Sanofi to pay over $834m to the state of Hawaii for illegally marketing their blood-thinning drug Plavix.

Ochiai said that the companies failed to properly warn non-white patients of health risks from Plavix and marketed the drug disclosing that it could have a reduced or no effect on some individuals, particularly of East Asian and Pacific Island ancestry.

Plavix is indicated to prevent strokes and heart attacks and requires activation through the enzymes in the body, which could vary depending on the genetics of the person, Reuters reported.

The news agency quoted Ochiai as saying that from 1998 to 2010 the companies engaged in unfair and deceptive business practices by not changing the drug’s label to warn doctors and patients despite knowing some of its risks.

Hawaii Attorney General Clare Connors, whose office took legal action against the companies in 2014, said the latest order “puts the pharmaceutical industry on notice that it will be held accountable for conduct that deceives the public and places profit above safety.”

BMS and Sanofi, in a joint statement, vowed to appeal, saying the decision was “unsupported by the law and at odds with the evidence at trial.”

The companies collaborated to produce Plavix and called the drug safe and effective.

Ochiai, who presided over a non-jury trial for four weeks, conducted online owing to the Covid-19 situation.

The judge ordered BMS and Sanofi to each pay $417m in penalties.

According to studies, around 14% of patients in China cannot metabolise the drug properly as compared with 4% of Black and 2% of white patients.

In 2010, the US Food and Drug Administration issued a new Plavix warning label to reflect that information.

The companies are facing a similar lawsuit over Plavix by the state of New Mexico.