Japan's biggest drug maker, Takeda Pharmaceutical, said it would fight a huge US$6 billion damages order imposed by a US jury following a trial over the safety of its Actos diabetes medicine.
The company said it "respectfully disagrees" with the judgment awarded in the southern state of Louisiana on Monday, which also ordered the firm's co-defendant, US drugs firm Eli Lilly, to pay US$3 billion in damages.
Takeda's Tokyo-listed shares slumped 5.16 per cent to 4,572 yen (HK$344) yesterday after the court decision.
The issue at the trial, which began in February, was whether the drug could be blamed for bladder cancer in a plaintiff who was taking the medicine and whether the firm knew about those risks. Other US cases over the drug are still pending.
"Takeda respectfully disagrees with the verdict and we intend to vigorously challenge this outcome through all available legal means, including possible post-trial motions and an appeal," Kenneth Greisman, senior vice-president and general counsel for Takeda's US unit, said.
"We believe the evidence did not support a finding that Actos caused [the plaintiff's] bladder cancer. We also believe we demonstrated that Takeda acted responsibly with regard to Actos."
While Takeda rang up about half its US$15 billion sales in Japan in the last fiscal year, North America and Europe are also major markets.
Eli Lilly had partnered Takeda in helping to market the drug in the United States.
Actos - a prescription medication launched in 2010 to improve blood sugar control in adults with type 2 diabetes - had been a promising drug for Takeda, which was recently forced to cancel development of another diabetes treatment due to safety concerns.
The US Food and Drug Administration in 2011 issued a safety alert, warning about the possibility of an increased bladder cancer risk with long-term use. The drug is banned in France and Germany.
The US judgment comes a week after former GlaxoSmithKline executive Christophe Weber was installed as Takeda's chief operating officer, one of the few foreign-born managers to sit in the top ranks of a Japanese firm.