The US FDA’s Center for Drug Evaluation and Research (CDER) has proposed withdrawing market approval of Tavneos (avacopan), a complement C5a receptor inhibitor marketed by ChemoCentryx, a wholly owned subsidiary of Amgen, for the treatment of severe active anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis in adults. The agency cited two grounds: that new information indicates the drug has not been shown effective for its approved use, and that the original application contained “untrue statements of material fact”.
Tavneos received FDA approval in October 2021 as an adjunct to glucocorticoids and other standard-of-care therapies in granulomatosis with polyangiitis and microscopic polyangiitis, rare diseases characterized by inflammation of small-to-medium-sized blood vessels. CDER’s proposal, which has been issued alongside a notice of opportunity for a hearing to ChemoCentryx and Amgen, marks one of the more consequential regulatory actions in the rare autoimmune disease space in recent years.
The agency stated that unblinded study personnel manipulated results from the pivotal clinical study supporting the original approval, altering the analysis so that the drug appeared effective when the original data did not support that conclusion. The applicant did not disclose the original analysis to the FDA, CDER said, in violation of agency regulations. This information only became known to CDER more than three years after the 2021 approval. CDER said it can no longer conclude that there is, or has ever been, a valid demonstration that Tavneos is effective for its approved use.
Separately, CDER identified cases of serious drug-induced liver injury associated with Tavneos, including cases involving vanishing bile duct syndrome, a condition characterized by progressive destruction of bile ducts in the liver. Some cases resulted in fatal outcomes. While hepatotoxicity had been identified as a known adverse reaction in premarket trials and included in product labeling, vanishing bile duct syndrome and fatal liver injury outcomes represent new safety concerns identified post-approval, the agency said in a March 31, 2026 drug safety communication.
Tavneos will remain on the market while the regulatory process proceeds. ChemoCentryx and Amgen may request a hearing before the FDA Commissioner, who would then determine whether to hold a public hearing and subsequently decide whether to withdraw approval. CDER recommended that healthcare professionals discuss the drug’s status and available treatment alternatives with patients in the interim.