Bristol-Myers Squibb Co. and Sanofi fought back against an $8 billion lawsuit filed by Hawaii over marketing of their blockbuster blood-thinning drug Plavix, arguing in a counter-suit that the state is trampling on their free-speech rights by demanding unnecessary warning labels.

Hawaii claims the companies misleadingly marketed Plavix and failed to properly warn consumers in the state about its risks. The case is set for trial before a state-court jury in Honolulu in April, according to lawyers involved in the case. Bristol-Myers and Sanofi argue that should be put on hold while their constitutional claims are reviewed.

“Hawaii’s lawsuit to extract civil penalties from the companies is an effort to compel speech,” lawyers for Bristol-Myers and Sanofi said in the suit, filed Tuesday in federal court in Honolulu.

Krishna Jayaram, a spokesman for Hawaii Attorney General Clare Conners, didn’t immediately return a call for comment.

Hawaii and New Mexico, which has also sued over the drug’s marketing, contend the drugmakers didn’t disclose that the blood thinner, which generated $6.6 billion in sales in 2011, isn’t effective on as much as 30% of users. Many of the people who found it ineffective are of Asian or Pacific-Island decent.

These users don’t properly metabolize the drug due to a genetic trait, the states allege. The drugmakers dispute that claim in their countersuit, saying “Plaix works as well if not better for patients of Asian decent” than other blood thinners.

According to Hawaii’s suit, rather than preventing heart attacks or strokes, Plavix puts those users at risk for gastrointestinal bleeding. The state claims the companies should have informed consumers that a simple genetic test could tell if the drug would be effective, a move the drugmakers also reject as violating their free-speech rights.

Defending Plavix

The companies have been battling Plavix suits for more than a decade, convincing a federal judge in New Jersey in 2018 to dismiss the scientific basis for the suits as unreliable.

Bristol-Myers and Sanofi agreed last year to pay West Virginia a combined $3.2 million to settle its Plavix marketing suit. Sanofi agreed to resolve a similar case by Mississippi for more than $2.6 million.

Bristol-Myers also persuaded the U.S. Supreme Court in 2017 to throw out a Plavix case that sought to combine the claims of more than 80 California residents with those of nearly 600 plaintiffs from about three dozen states on procedural grounds.

In the Hawaii case, the drugmakers want a federal judge to find the state is unfairly punishing them for not agreeing to put what they call an unnecessary warning on Plavix voluntarily. In 2010, federal regulators forced them to strengthen the drug’s warnings. But some medical experts said the move was premature based on studies of the drug’s effectiveness and safety at the time.

“The prospect of this massive liability for making truthful statements about their products and for failing to make untruthful statements has a chilling effect on speech not only of these companies, but of other pharmaceutical manufacturers as well,” Bristol-Myers and Sanofi said in the complaint.

The case is Bristol-Myers Squibb Co. v. Conners, 20-cv-00010, U.S. District Court, District of Hawaii (Honolulu).