The U.S. Food and Drug Administration’s Center for Drug Evaluation and Research issued a formal proposal on April 27, 2026 to withdraw approval of Amgen’s drug Tavneos (avacopan), a treatment for the rare autoimmune disease pauci‑immune glomerulonephritis. The proposal cites a lack of proven effectiveness, allegations that Amgen misrepresented data in the original approval application, and new safety concerns, including 76 reported cases of drug‑induced liver injury, seven instances of vanishing bile duct syndrome, and eight deaths.
Tavneos generated $71 million in U.S. sales in the second quarter of 2024 and $459 million for the full year 2025, a 65% year‑over‑year increase in U.S. sales. The drug is projected to reach $600 million in 2026 and could account for roughly 1.2% of Amgen’s total revenue in 2025, underscoring its role as a key growth engine in the company’s rare‑disease portfolio.
Amgen has stated it does not plan to voluntarily withdraw Tavneos and remains confident in its safety and effectiveness. “We remain confident in TAVNEOS as a safe and effective medicine, supported by years of clinical data and real‑world evidence. Our perspective on the benefit‑risk profile of TAVNEOS differs from the Agency’s. We will evaluate next steps and respond to the FDA, while keeping patient needs and support at the forefront,” the company said. Executive VP James Bradner added, “We were surprised by this. But after review, Amgen is certain that Tavneos is effective and has a favorable benefit‑risk profile.” A February 3 release reiterated that Amgen was not aware of any issues with the underlying patient data from the ChemoCentryx trial and that its review of clinical findings and real‑world evidence supports the drug’s effectiveness.
The FDA’s withdrawal proposal initiates a formal process that will notify Amgen, provide an opportunity for a hearing, and allow for written appeals. If the FDA’s concerns are upheld, the drug would be removed from the market, eliminating a significant revenue stream and potentially exposing Amgen to heightened regulatory scrutiny and reputational damage. The outcome could also influence the company’s broader rare‑disease strategy, as Tavneos was part of the $3.7 billion acquisition of ChemoCentryx in 2022 and was approved in October 2021.
The event highlights the risks inherent in Amgen’s rare‑disease expansion strategy. While the company’s portfolio has driven growth, the Tavneos case underscores the importance of rigorous data integrity and safety monitoring. A withdrawal would not only reduce Amgen’s revenue but could also prompt closer examination of other products in the portfolio, affecting investor confidence and the company’s competitive positioning in the rare‑disease market.
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