U.S. FDA and EU’s EMA Move to Pull Avacopan After Liver Safety Alarms
Nikhil Prasad Fact checked by:Thailand Medical News Team Feb 07, 2026 2 hours, 32 minutes ago
Medical News:
Drug Regulators on Both Sides of the Atlantic Raise Serious Concerns
Regulatory pressure is mounting against avacopan, marketed as Tavneos, after both the U.S. Food and Drug Administration and the European Medicines Agency signaled that the drug’s future on the market is in jeopardy. The oral therapy, approved for the treatment of anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis, is now under intense scrutiny due to unresolved concerns over liver toxicity and questions surrounding the integrity of pivotal clinical trial data. These developments have sent shockwaves through the medical community and raised uncertainty for patients relying on the drug.
Mounting regulatory pressure threatens the future of a once promising vasculitis therapy amid liver safety fears
Background Of Avacopan and Its Approval Pathway
Avacopan was originally developed by ChemoCentryx and later acquired by Amgen in 2022. The drug acts as a complement 5a receptor inhibitor, targeting excessive immune activation that drives inflammation in granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA). These rare autoimmune diseases can lead to severe organ damage, particularly of the kidneys, and may become fatal if not effectively managed. Tavneos received FDA approval in 2021 and European Union approval in 2022 as an add-on therapy to standard immunosuppressive treatments such as rituximab or cyclophosphamide.
ADVOCATE Trial Findings Under the Microscope
Regulatory approvals were largely based on results from the Phase III ADVOCATE trial involving 331 adult patients. The study compared avacopan with a prednisone taper regimen, both alongside standard immunosuppressive therapy. At 26 weeks, remission rates were similar between groups, meeting non-inferiority criteria. At 52 weeks, sustained remission appeared higher in the avacopan group. However, regulators later questioned whether these benefits could truly be attributed to avacopan, given that many patients also received glucocorticoids during the study, potentially confounding the results.
Data Integrity and Subgroup Analysis Concerns
The FDA highlighted issues related to the re-adjudication of primary endpoint data in nine patients, raising alarms about trial processes. Subgroup analyses further complicated interpretation, showing superiority primarily among patients receiving rituximab who may not have been on standard maintenance therapy. Regulators warned that these patients might have been undertreated, making the comparative benefit of avacopan less clinically meaningful than initially believed.
Hepatotoxicity Risks Take Center Stage
Beyond efficacy doubts, liver safety has emerged as a critical issue. Serious liver-related adverse events occurred more frequently in patients receiving avacopan compared to prednisone in the ADVOCATE trial. Although hepatotoxicity is already listed as a known risk on the drug label, regulators now question whether the overall benefit-risk balance remains acceptable. Allegations from a U.S. lawsuit claim that early warnings about potential severe liver injury were minimized during development, intensifying regulatory c
oncerns. This
Medical News report notes that the EMA has launched a full reassessment to determine whether Tavneos’ approval should be maintained, amended, suspended, or revoked.
What This Means for Patients and Clinicians
Amgen has stated it does not currently plan to withdraw the drug and maintains confidence in its safety and effectiveness, while cooperating with ongoing regulatory reviews. However, both U.S. and European regulators have made it clear that patient safety will drive final decisions. For clinicians and patients, the situation underscores the importance of vigilant liver monitoring and reassessment of treatment strategies should avacopan’s availability change.
The unfolding regulatory actions highlight how unresolved safety signals and trial ambiguities can reshape the fate of a drug even years after approval, potentially redefining standards for rare autoimmune disease therapies worldwide.
References:
https://www.ema.europa.eu/en/news/ema-starts-review-tavneos-medicine-rare-autoimmune-diseases-gpa-mpa
https://static.blbglaw.com/docs/March%2028%2C%202022%20-%20Amended%20Consolidated%20Class%20Action%20Complaint.pdf
https://www.amgen.com/tavneos-prescribers
https://www.accessdata.fda.gov/drugsatfda_docs/label/2024/214487Orig1s004lbl.pdf
https://www.accessdata.fda.gov/drugsatfda_docs/nda/2021/214487Orig1s000AdminCorres.pdf
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