Kissei Ordered to Warn over Vasculitis Drug after Fatalities

From Jiji

May 21 2026

TOKYO – Japan’s health ministry on Thursday ordered Kissei Pharmaceutical Co. to add a warning to the package insert of Tavneos, a drug for vasculitis, or blood vessel inflammation, after the deaths of 20 patients who took the medicine. 
   To alert medical staff, the Japanese drugmaker was ordered to stipulate the fact that patients have died after developing liver dysfunction following the use of the prescription drug.
   Tavneos, developed by a U.S. drugmaker, was approved by the ministry and launched in Japan in June 2022, with its package insert citing liver dysfunction as a possible serious side effect.
   The drug is estimated to have been administered to 12,000 to 13,000 patients in Japan. All 20 dead patients developed liver dysfunction, and 210 similar side effect reports have been made, including suspected cases.
   The ministry has already warned against newly administering the drug to patients.