Regulators on both sides of the Atlantic are pushing for the withdrawal of the rare disease treatment that accounted for just 1% of Amgen’s 2025 revenue. Nevertheless, Amgen continues to defend the medicine, which was acquired in the $3.7 billion buyout of ChemoCentryx.
The pressure on Amgen’s Tavneos is ratcheting up ahead of a potential hearing about the future of the drug. Since the FDA proposed withdrawing approval in April, a journal has retracted a key paper on the rare disease drug, the European Medicines Agency has recommended revoking authorization and Amgen’s Japanese partner has reportedly urged doctors not to start patients on the medicine. Yet Amgen continues to defend a product that accounted for 1% of revenues last year.
Amgen acquired Tavneos in 2022 through the $3.7 billion takeover of ChemoCentryx, less than a year after the FDA approved the drug to treat a rare autoimmune disorder called ANCA-associated vasculitis. In January, Amgen refused the FDA’s request to withdraw the drug over concerns about ChemoCentryx’s pivotal trial. Three months later, the FDA formally proposed withdrawing approval.
The biotech has called on the FDA to grant a hearing on the proposed withdrawal. A few weeks later, the New England Journal of Medicine retracted a paper about ChemoCentryx’s pivotal clinical trial of Tavneos that had supported the drug’s approval and reimbursement decisions. Still, Amgen continues to oppose the FDA’s plans to withdraw the drug.
Amgen “takes scientific integrity seriously and respects the role of journals in upholding the peer review process,” a spokesperson for the biotech told BioSpace via email. The NEJM concluded that an aspect of the data analysis was “inconsistent with proper research conduct.” Specifically, endpoint assessments for nine patients were readjudicated after all the clinical trial data had been collected and the database locked. This aligns with the FDA’s concerns, but Amgen argues that the evidence still shows that the benefits of Tavneos outweigh the risks.
“In February 2026, Amgen proactively initiated an independent, fully blinded re-adjudication of the primary endpoint results from the ADVOCATE study conducted by the Duke Clinical Research Institute,” the spokesperson said. “Those results will be shared with the FDA as part of our hearing submission due by July 29 and submitted for publication.”
Amgen has opted to defend Tavneos after spending “several months collecting Phase 3 data both pre- and post-database lock, real-world data and pharmacovigilance data,” Guggenheim Securities said in a note to investors in June.
The impact of withdrawal
Amgen is defending a product that, by its own admission, is relatively insignificant from a commercial perspective. Tavneos is “a very small product in our portfolio relative to the other things we have going on,” Amgen CEO Robert Bradway said on the company’s fourth-quarter earnings call in February. Sales of Tavneos hit $459 million last year. The U.S. accounted for 92% of the product’s sales.
Tavneos is, however, one of the fastest-growing medicines in Amgen’s portfolio. Sales jumped 62% last year and rose 32% in the first quarter of 2026. Analysts predicted further growth, at least before doubts about the future of Tavneos intensified. Sales of the drug could reach $1.1 billion by 2034, RBC Capital Markets said in a note to investors in April. InflaRx, a potential rival to Amgen, has quoted a $1.3 billion peak sales figure.
The forecasts suggest that, if Amgen can resolve the current challenges, Tavneos can support the growth of its rare disease franchise, which includes a blockbuster gout drug, Krystexxa, that could face biosimilar competition in the coming years. RBC analysts predict that Krystexxa sales will start to fall after 2029. Still, Tavneos is a supporting player, not a star drug.
“Tavneos is not large enough to materially alter Amgen’s consolidated growth outlook,” BMO Capital Markets analysts said in a note to investors. The NEJM retraction was therefore “an incremental negative rather than a thesis-changing event.”
Guggenheim Securities analysts significantly reduced their long-term sales forecasts for Tavneos in May to reflect the new developments. But the financial implications of withdrawing Tavneos extend beyond the loss of a small but growing revenue stream. Intangible assets related to the drug had a carrying value of $2.4 billion at the end of March, $2.3 billion of which was tied to the U.S. market. Changes to estimated Tavneos cash flows could hurt Amgen’s ability to recover value tied to the acquisition of ChemoCentryx, the company told investors.
Withdrawing the medicine would also affect patients, of course. Responding to the FDA’s withdrawal proposal, the Eosinophilic & Rare Disease Cooperative urged the agency to keep Tavneos on the market. Withdrawing the drug “would cause serious, lasting harm” to people with ANCA vasculitis, the patient advocacy group told the FDA. Another patient group, the Vasculitis Foundation, told the FDA that alternatives to Tavneos have serious risks.
The FDA’s powers
The FDA has the power to order the withdrawal of drugs, but the process can take years and is rarely used. In May, the FDA seemingly ended the 23-year wait for a conclusion to one withdrawal saga, only to delay implementation of its decision by three months “to consider issues raised by interested parties.” If implemented, the FDA decision will make it unlawful to sell certain women’s health drugs.
Attempts to withdraw products with accelerated approvals after failed confirmatory trials also involve a protracted process. The agency reached a final decision on Covis Pharma’s Makena in April 2023, three years and one advisory committee after proposing to withdraw accelerated approval of the drug for preventing premature births.
The next steps in the Amgen case will depend on the FDA’s assessment of the 67 comments submitted in response to the agency’s call for public feedback. The FDA closed the docket on June 29, but Amgen has until July 29 to submit additional materials, BMO analysts said.
