The European Medicines Agency (EMA) has recommended that marketing authorisation for Tavneos (avacopan) be revoked due to a question mark over the integrity of clinical data used to support its initial approval.
The guidance comes after the agency’s human medicines committee (CHMP) conducted a review to assess new information relating to the Phase III Advocate study, which served as the primary data package for Tavneos’ marketing authorisation in 2022.
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Tavenos was developed by US biopharma ChemoCentryx, which was later acquired by Amgen for $3.7bn in 2022. Amgen took on US rights for the drug, while European commercialisation is handled by CSL Vifor.
The therapy is indicated for the treatment of adults with severe, active granulomatosis with polyangiitis (GPA) or microscopic polyangiitis (MPA), two rare inflammatory conditions of the blood vessels.
As per the Advocate trial, the drug was found to be as effective as high-dose corticosteroids in inducing remission and better at maintaining long-term remission rates.
However, the integrity of those findings is now in question. After reviewing all available data and new information on how the study data were handled, the CHMP concluded that the Advocate study was conducted in breach of good clinical practice (GCP) principles.
The EMA stated that: “Study data provided at the time was misleading and could no longer be relied upon for demonstrating Tavneos’ effectiveness.”
This, the agency added, means the medicine’s benefits are no longer proven to outweigh its risks. Given that post-marketing data and further analysis of the study are insufficient to prove this, the CHMP recommended that Tavneos’ marketing authorisation be revoked. As part of this, the committee advised that no new patients should start treatment with the drug, and that existing patients should be switched to suitable alternatives.
The decision follows a similar move by the US Food and Drug Administration (FDA) in April 2026. The agency’s Center for Drug Evaluation and Research (CDER) proposed withdrawing the drug from the market after deeming that personnel had manipulated the results of the pivotal clinical study, so the drug looked effective when the original analysis did not support that conclusion. The CDER was also concerned about Tavneos’ safety, highlighting drug-induced liver injury in some patients.
CSL Vifor’s head of R&D Bill Mezzanotte said in a statement: “While we are disappointed in the outcome of the Article 20 procedure, we will respect the outcome of the regulatory process and are committed to implementing it in full…Patient care remains our highest priority, and we are working closely with regulatory authorities, healthcare professionals and patient organisations to ensure a compliant and appropriate treatment transition, along with ongoing support for patients.”
The review comes after 20 deaths were reported in Japan earlier this year among patients prescribed Tavneos. Fatalities involved severe liver complications like vanishing bile duct syndrome. In a March 2026 safety alert, the FDA noted 76 cases of liver injury in its own review.
In a statement in May 2026, Amgen said that the Japanese regulatory notification “lacked important context.”
The pharma company stated: “These figures include cases for which a causal relationship with the product could not be determined. There have been no known deaths in the US linked to serious liver injury, including vanishing bile duct syndrome (VBDS), in the more than 8,000 patients in the US treated with Tavneos.”
Amgen has recruited a research firm to independently review Tavneos’ data package, as it seeks to prove the drug’s benefits before a hearing with the FDA.
