The FDA proposed withdrawing Tavneos from the US market in April, citing data manipulation by ChemoCentryx employees and reports of serious liver injuries. The drug, which treats ANCA-associated vasculitis, was approved in October 2021 based on a narrowly voted advisory committee recommendation, despite concerns about study design quality.
ChemoCentryx, the California biotech company that developed Tavneos, was acquired by Amgen for nearly $4 billion one year after approval. Tavneos generated sales of nearly half a billion dollars in fiscal year 2025 at a cost of $220,000 per year.
The New England Journal of Medicine retracted the clinical trial paper this summer. The European Union removed the drug from the market, and the United Kingdom announced it will do the same. A court hearing scheduled for October 29 is expected to address a proposed $69 million settlement in a long-running investor lawsuit that uncovered the data manipulation allegations.
Amgen has defended the drug, submitting a 104-page document to the FDA stating that evidence supports Tavneos remaining on the market. Some patients and academic experts, including epidemiologist Eric Roberts at the University of California, San Francisco, also believe the drug is an important treatment option that could reduce reliance on steroids, which carry severe side effects.
The case highlights the FDA's difficulty regulating drugs with uncertain efficacy and raises questions about safeguards when small companies conduct pivotal trials with significant financial stakes in a single drug's success.