20 People in Japan Died After Taking Amgen Drug -- WSJ

By Xavier Martinez

Twenty people in Japan who took Amgen's rare-disease drug Tavneos have died, and at least 22 developed a potentially fatal liver injury, according to Kissei Pharmaceutical, which sells the medicine in the country.

Kissei told doctors Friday to stop prescribing the drug to new patients.

The Japanese drugmaker said the 20 deaths occurred in people who had suffered a serious liver "impairment" and attributed 13 of the deaths to a condition, called vanishing bile duct syndrome, marked by the destruction of the ducts that carry bile out of the liver.

Kissei said causal links to Tavneos hadn't been confirmed in all 20 deaths. Amgen shares were down more than 2% late Friday.

An Amgen spokeswoman referred questions to CSL Vifor and Kissei, which licenses the drug in Japan from the American biotech. CSL, which licensed the drug to Kissei, said it "takes all matters of patient safety seriously" and committed to working with regulators.

"Kissei has begun providing information to healthcare professionals, urging them to refrain from using this drug for new patients and to carefully assess the continuation of treatment for existing patients, explaining the risks of liver dysfunction and alternative treatments to ensure patient safety," the company said.

Tavneos treats a group of rare autoimmune diseases that cause inflammation in small blood vessels. The U.S. Food and Drug Administration approved it in 2021.

The medicine went on sale in Japan in 2022, according to Kissei. Also that year, Amgen bought the drug's developer, ChemoCentryx, for $3.7 billion.

In January, the FDA asked Amgen to voluntarily pull the drug from the U.S. market, but Thousand Oaks, Calif.-based Amgen refused.

Then in March, the FDA said it had identified 76 global cases of serious liver injury linked to Tavneos, including eight deaths. Most were reported in Japan. Of the 76 global cases the FDA identified, seven involved the syndrome, and three of those patients died.

In late April, the FDA moved to formally begin withdrawal proceedings.

The FDA has also said that ChemoCentryx had included material misstatements in its original approval application.

Tavneos generated $119 million in sales in the first quarter for Amgen, up 32% from a year earlier, and accounting for less than 2% of the company's overall drug sales.

Amgen said in its quarterly earnings release in late April that the drug "demonstrates effectiveness and a favorable benefit-risk profile," and said that vanishing bile duct syndrome hadn't affected patients in the U.S.

Write to Xavier Martinez at xavier.martinez@wsj.com

(END) Dow Jones Newswires

May 15, 2026 15:37 ET (19:37 GMT)

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