FDA is alerting patients and health care professionals about serious postmarketing cases, including fatal cases, of drug-induced liver injury (DILI) associated with Tavneos (avacopan). Some cases involved vanishing bile duct syndrome (VBDS), which is characterized by progressive destruction and disappearance of the bile ducts in the liver. This condition can slow or stop the flow of bile and may lead to permanent liver damage. VBDS is often accompanied by the yellowing of skin or eyes (jaundice), itchiness, and tiredness.