FDA Seeks to Withdraw Tavneos Approval as Amgen Pushes Back

A narrow vote by an FDA advisory committee in 2021 is now colliding with a federal effort to undo it. The US Food and Drug Administration wants Tavneos, a $220,000-a-year drug for a rare form of vasculitis, off the market. Five years after approval, the agency says the evidence behind that approval was compromised. Pulling the drug, it turns out, is not a simple matter of flipping a switch.

What did the FDA find wrong with Tavneos's approval?

The FDA approved Tavneos on October 7, 2021, after an advisory committee voted narrowly to recommend it, according to Undark Magazine's reporting via Ars Technica. At the time, one committee member said the drug's effect was "just not well verified" by the underlying study, which had been run by ChemoCentryx, the California biotech that developed it. An investor lawsuit later surfaced evidence the FDA now cites as proof that ChemoCentryx employees manipulated data in that pivotal trial. In April 2026, the agency issued a letter proposing withdrawal, pointing to reports of serious — in some cases fatal — liver injury and arguing the drug no longer has "substantial evidence" of effectiveness, per the FDA letter described in the same report.

How much money is riding on the outcome?

Two figures frame the stakes. Tavneos carries a list price of $220,000 per year, according to Drugs.com, cited in the Ars Technica account. And in fiscal year 2025, sales of the drug reached nearly half a billion dollars, the report states, a figure recorded well after the data-manipulation evidence had emerged in litigation. Amgen, which is one of the world's largest pharmaceutical companies, acquired ChemoCentryx a year after approval, in 2022. That acquisition means Amgen — not the company that ran the disputed trial — is now the one defending the drug's place on the market.

Why can't the FDA just withdraw the drug?

Withdrawing an approved drug in the United States is not an administrative formality; it is a contested regulatory process, and Amgen is contesting it. In July 2026, Amgen submitted a 104-page document to the FDA arguing that "the totality of the evidence supports the continued availability of TAVNEOS," according to the company's filing as described in the Ars Technica report. The company's position is that whatever ChemoCentryx did with its data, the drug's clinical effect is real. That dispute — over whether flawed data handling by the original trial sponsor invalidates a drug's efficacy case entirely, or whether other evidence can stand on its own — is the crux of why the FDA's April letter has not translated into an immediate market exit.

How have regulators outside the US responded?

Other regulators have moved faster. This summer, Tavneos was taken off the market in the European Union, the report notes, and the United Kingdom has announced it will remove the product from its market as well. The New England Journal of Medicine also retracted the paper describing the original clinical trial this summer — a separate but related repudiation of the data that underpinned the 2021 approval. The US has not followed those jurisdictions in actually removing the drug; it remains available to patients while the FDA's withdrawal proposal and Amgen's rebuttal are worked through.

What is happening with the investor lawsuit?

The data-manipulation evidence did not originate with FDA inspectors — it surfaced through a long-running investor lawsuit against ChemoCentryx. A court hearing was expected to proceed by Zoom on October 29, 2026, to consider a proposed $69 million settlement in that case, according to the Ars Technica account. That settlement, if approved, resolves the financial claims of investors who argued they were misled about the trial. It does not resolve the separate, slower-moving question the FDA is wrestling with: whether patients currently taking Tavneos, and the physicians who prescribe it for symptom remission in a disease that often damages the kidneys and lungs, should still have access to it. Some patients and academic experts, the report notes, continue to view the drug as an efficacious alternative to long-term steroid use, which carries its own well-documented side effects. That clinical argument — not just the data-integrity dispute — is likely to shape how long Tavneos stays on US pharmacy shelves while the agency's withdrawal process plays out.