The U.S. Food and Drug Administration identified 76 cases of drug‑induced liver injury that were reasonably linked to Amgen’s rare‑disease therapy Tavneos, a treatment for severe active anti‑neutrophil cytoplasmic autoantibody (ANCA)‑associated vasculitis. 74 of the cases had serious outcomes, including 54 hospitalizations and eight deaths, underscoring the seriousness of the safety signal.
The warning follows an earlier FDA request in January 2026 for Amgen to voluntarily withdraw Tavneos from the U.S. market because of methodological concerns about a clinical trial and hepatotoxicity risks. Amgen declined the request, and the European Medicines Agency has begun a review of the drug’s data integrity. Amgen has also asked the FDA to add vanishing bile duct syndrome (VBDS) to the label in 2024, a request that remains pending. Despite the heightened scrutiny, Amgen’s leadership has reiterated confidence in Tavneos’s benefit‑risk profile, citing robust clinical data and real‑world evidence.
Tavneos has been a strong growth driver for Amgen’s rare‑disease portfolio. In 2025 the drug generated $459 million in sales, a 62% year‑over‑year increase. The fourth quarter of 2024 saw $81 million in sales, an 84% jump, and U.S. sales for the first nine months of 2025 reached $301 million, up 49% from the same period a year earlier. The FDA warning could lead to reduced prescribing, patient hesitancy, and a potential decline in sales and brand reputation.
The warning adds to regulatory scrutiny that already includes the January 2026 withdrawal request and the EMA review. Tavneos is the only FDA‑approved, targeted oral treatment for GPA and MPA, and its first‑in‑class status makes it a key product for Amgen’s rare‑disease strategy. The safety signal may prompt clinicians to exercise greater caution, potentially impacting market share and the company’s ability to sustain its rapid growth in this segment.
Tavneos was approved by the FDA in October 2021 and was developed by ChemoCentryx, which Amgen acquired in October 2022. The drug is an oral small‑molecule inhibitor of the C5a receptor, blocking the pro‑inflammatory complement fragment C5a. Hepatotoxicity is a known, infrequent risk that was included in the original label, and the current warning highlights serious post‑marketing cases, including fatal outcomes and VBDS.
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