Amgen has submitted a comprehensive data and analyses package to the FDA as it fights to keep its rare-disease drug Tavneos on the U.S. market.
The submission, filed on July 23, directly contests the FDA’s April 2026 proposal to withdraw Tavneos, which alleged the original approval application contained untrue statements of material fact.
“Amgen strongly disagrees with the FDA’s proposal to withdraw Tavneos from the U.S. market,” the company said in a statement issued Friday.
The package includes more than 70 real-world studies involving over 2,200 patients, which Amgen says supports the drug’s effectiveness and safety profile.
The FDA’s withdrawal proposal cited new information indicating that unblinded study personnel manipulated results of the pivotal Phase III ADVOCATE trial to make the drug appear effective when the original analysis did not support that conclusion.
In response, Amgen said it proactively initiated an independent, fully blinded re-adjudication of the primary endpoint results from the ADVOCATE study, conducted by the Duke Clinical Research Institute.
“Those results will be shared with the FDA as part of our hearing submission due by July 29 and submitted for publication,” an Amgen spokesperson said.
On safety, the FDA reported that between Tavneos’ approval and October 2024, 76 cases of drug-induced liver injury with reasonable evidence of a causal association were reported to its adverse event reporting system.
Nearly all those cases resulted in serious outcomes, including hospitalisation in 54 patients and death in eight, according to the FDA’s own figures.
Amgen acknowledged post-marketing cases of serious hepatic injury, including vanishing bile duct syndrome with fatal outcomes, predominantly in Japanese patients aged 65 and older.
The company said updated hepatotoxicity warnings became effective May 29, 2026, and that its safety database analysis supports liver monitoring as a risk mitigation measure rather than grounds for market withdrawal.
Since the FDA proposed the withdrawal in April, a journal retracted a key paper on the drug, the European Medicines Agency recommended revoking its authorisation, and Amgen’s Japanese partner reportedly urged doctors not to start new patients on the medicine.
ChemoCentryx, Amgen’s wholly owned subsidiary and the NDA holder, may formally request a hearing under the applicable regulatory framework before any final withdrawal decision is made.
The FDA Commissioner will then determine whether a genuine and substantial issue of fact exists to warrant a full public hearing, with Tavneos remaining commercially available in the U.S. in the meantime.
Tavneos generated sales of $462 million last year, a 62% increase versus 2024, but first-quarter sales fell to $119 million, representing a 22% sequential decline amid the mounting regulatory pressure.
Amgen acquired Tavneos in 2022 through its $3.7 billion takeover of ChemoCentryx, less than a year after the FDA approved the drug to treat ANCA-associated vasculitis, a rare autoimmune disorder that can lead to organ failure and is often fatal without treatment.