FDA Seeks Withdrawal of Tavneos Amid Data Manipulation Allegations
The agency argues the rare‑disease drug lacks solid evidence after uncovering manipulated trial data.
FDA’s New Withdrawal Proposal
The U.S. Food and Drug Administration released a briefing in May 2021 on an experimental therapy for a rare autoimmune vasculitis that can damage kidneys and lungs. After a narrow advisory committee vote, the agency approved the drug, marketed as Tavneos, on October 7, 2021.
In April of this year, the FDA sent a letter proposing that Tavneos be withdrawn from the U.S. market. The regulator cited reports of serious, sometimes fatal, liver injury and argued the drug no longer has “substantial evidence” of efficacy.
Origins of the Controversy
The pivotal trial was conducted by California biotech ChemoCentryx. The FDA later concluded that employees at ChemoCentryx manipulated data submitted for approval. While the study showed slightly higher remission rates after one year, the agency said the trial design was suboptimal, making the results hard to interpret. An advisory committee member described the effect as “just not well verified by this study.”
Despite these concerns, many patients and physicians saw potential in a drug that could reduce reliance on high‑dose steroids, which are effective but cause severe side effects.
Commercial Impact and Legal Battles
One year after approval, Amgen acquired ChemoCentryx. Tavneos now costs $220,000 per year, according to Drugs.com, and generated nearly half a billion dollars in sales in fiscal year 2025.
A long‑running investor lawsuit uncovered the alleged data manipulation. This summer, the New England Journal of Medicine retracted a paper describing the trial, and the European Union removed the product from its market. The United Kingdom announced a similar removal. A court hearing scheduled for October 29 will consider a proposed $69 million settlement.
Amgen’s Defense and Expert Opinions
Amgen submitted a 104‑page document to the FDA in July, asserting that “the totality of the evidence supports the continued availability of TAVNEOS.” The company maintains that, regardless of the data handling issues, the drug works as advertised.
Some experts agree. Eric Roberts, an epidemiologist at the University of California, San Francisco, co‑authored an independent registry study and called Tavneos “an efficacious medication.”
Broader Regulatory Implications
Regulators are grappling with how to manage drugs approved on limited or questionable evidence. Reshma Ramachandran, a physician and co‑director of the Yale Collaboration for Regulatory Rigor, Integrity, and Transparency, warned that without more rigorous studies, “we’re just going to be living in uncertainty in terms of whether or not these drugs actually work.”
The Tavneos saga raises questions about safeguards for drug approvals, especially when a small company conducts the pivotal trial and stands to gain enormously from a single product.
Patient Perspective
Chloe Cusanowa, a 20‑year‑old diagnosed with ANCA‑associated vasculitis in December, described the disease’s rapid progression and the harsh side effects of steroids, including weight gain, mood swings, insomnia and nightmares. She and other patients hope Tavneos could lessen or replace steroid use.
