Twenty deaths in Japan have prompted Kissei Pharmaceutical to call for an end to new prescriptions of Amgen's Tavneos drug. The recommendation follows careful review of safety data collected since the drug became available.
On May 15, 2026, Kissei issued a safety notice. The Japanese company told doctors to stop prescribing Tavneos to new patients and to review all current treatments because of the risk of severe liver damage. This step was taken after internal analysis showed a clear pattern of adverse events.
Twenty fatal cases of serious liver injury occurred among approximately 8,500 patients treated with Tavneos since its June 2022 launch in Japan. At least 22 additional patients suffered serious liver injury, including vanishing bile duct syndrome. These outcomes have raised questions about ongoing use in certain patient groups.
The action increases global regulatory pressure on the drug. The FDA issued a liver injury warning in March 2026. The agency proposed withdrawing U.S. approval in April 2026. Similar reviews are now underway in other regions where the medicine is marketed.
Amgen confirmed the Japanese findings. "Kissei, which owns the rights to TAVNEOS in Japan, reported 20 fatal cases of serious liver injury, from over 8,500 patients who have been treated with TAVNEOS in Japan," the company stated.
Reuters reported the Kissei safety notice that detailed the 20 deaths and liver injuries linked to Tavneos. The Wall Street Journal described the 20 deaths and 22 liver injury cases that led Kissei to urge a halt on new prescriptions. Kyodo News covered Kissei's direct recommendation that doctors refrain from prescribing Tavneos to new patients. Health authorities continue to monitor the situation closely and may issue further guidance soon.
