Avacopan Drug Withdrawal
European Medicines Agency Recommends Withdrawing Avacopan Due to Reported Fatal Liver Damage
The European Medicines Agency (EMA) recommended on June 26, 2026 that avacopan — sold as Tavneos — be pulled from the market across the European Union. The drug, used to treat two rare autoimmune diseases, has been linked to 76 cases of serious liver injury worldwide and at least 8 deaths, according to EMA and FDA findings. The move follows a nearly identical decision by the U.S. Food and Drug Administration in April 2026.
At the heart of the crisis is not only a safety scandal, but a data fraud. The pivotal clinical trial that won the drug its approval was found to have been manipulated after unblinding — a fundamental breach of scientific protocol. On June 29, the New England Journal of Medicine retracted the original 2021 study that made avacopan famous.
Trial Data Was Manipulated After Results Were Unblinded
Avacopan was developed to treat two rare forms of vasculitis — GPA and MPA — where the immune system attacks small blood vessels, damaging organs like the kidneys. It was praised as a "steroid-sparing" alternative, letting patients avoid the harsh long-term effects of high-dose prednisone. The FDA approved it in 2021 based on the ADVOCATE study, published in the New England Journal of Medicine.
But the trial's lead authors later discovered that company personnel had "readjudicated" — that is, re-evaluated — the outcomes of nine patients after the trial was unblinded and the database was locked. This is a major violation. The goal was to tip the results in the drug's favor after an early analysis in November 2019 failed to show superiority over steroids. The NEJM retracted the paper on June 29, 2026 at the authors' own request, according to Endpoints News.
Liver Damage and Deaths Triggered the Safety Alarm
Separate from the data fraud, real-world use of the drug revealed a dangerous pattern. The FDA identified 76 cases of drug-induced liver injury with a "reasonable evidence of a causal association" to avacopan. Seven of those cases involved Vanishing Bile Duct Syndrome (VBDS) — a rare condition where the bile ducts are progressively destroyed — and three of those patients died. The median time from first dose to liver injury was just 46 days, according to an FDA safety communication issued March 31, 2026.
In Japan, 20 deaths were reported among patients taking the drug, though manufacturer Amgen disputes a direct causal link in those cases, according to Endpoints News. The EMA concluded that the risks are no longer acceptable, especially now that the benefit data — built on a manipulated trial — can no longer be trusted. "The benefits are no longer proven to outweigh the risks," the agency stated.
Amgen's $3.7 Billion Bet on Tavneos Collapses
Amgen bought ChemoCentryx — the original developer of avacopan — for $3.7 billion in August 2022, largely to get Tavneos. The drug generated $459 million in sales in 2025 alone. That revenue stream is now expected to vanish in the EU and, eventually, in the U.S. market too, according to Endpoints News. Amgen has requested a formal hearing with the FDA to fight the U.S. withdrawal.
CSL Vifor, which sold the drug in Europe, said it would comply. Dr. Bill Mezzanotte, head of R&D at CSL, said: "While we are disappointed in the outcome... we will respect the outcome of the regulatory process and are committed to implementing it in full." Amgen, meanwhile, insists real-world data from over 8,000 patients proves the drug works and that liver risks are "manageable."
What Happens Now for Patients Already on the Drug
The EMA says no new patients should start Tavneos immediately. Patients already taking it must not stop abruptly — sudden withdrawal can be dangerous for people with severe vasculitis. Instead, they should contact their doctor to plan a switch to alternatives, such as corticosteroids or rituximab, a different type of immunosuppressant.
For patients who have recently stopped the drug, the EMA recommends liver function tests every two weeks for the first three months, then every four weeks for up to six months after stopping. Patient groups like Vasculitis International say the withdrawal leaves a serious gap in care for a life-threatening disease, but acknowledge the regulatory decision. Legal analysts expect class-action suits from patients who suffered liver damage, as well as shareholder claims against Amgen over its $3.7 billion acquisition, according to Reuters.
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