Drug Regulatory Bodies Advise Market Withdrawal of Tavneos Following Findings of Data Tampering
The drug regulatory bodies of the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA) have advised the removal of Tavneos (avacopan) from the market. This recommendation comes after the findings of an independent investigation conducted earlier this year, which revealed that ChemoCentryx staff, the drug’s original developers, manipulated data from the phase 3 trial to inaccurately enhance its efficacy. As a result, the credibility of the research has been compromised, prompting the New England Journal of Medicine to retract the trial report.
Avacopan, a small molecule inhibitor indicated for vasculitis—a condition marked by inflammation that restricts blood flow—was developed by ChemoCentryx. The FDA granted approval for the drug in October 2021, followed by EU authorization in January 2022. In October 2022, Amgen acquired ChemoCentryx for $3.7 billion.
Following these developments, ChemoCentryx shareholders initiated a lawsuit alleging securities fraud, which led to an independent investigation. In May 2025, the FDA revealed findings of data manipulation in the clinical trial, indicating that the drug was portrayed as effective despite initial analyses pointing to the contrary.
The report disclosed modifications in the trial outcomes for nine subjects, with results for five avacopan patients altered after the first blinded analysis. ChemoCentryx staff acknowledged that these changes made the study statistically significant, misleadingly indicating the effectiveness of avacopan.
Additionally, the FDA has raised safety concerns regarding Tavneos, noting instances of severe liver-related adverse events that were more serious than those identified during clinical trials. A notably high incidence of serious liver-related cases has been observed in Japan, leading Amgen to propose potential explanations such as genetic variations, different treatments, or inconsistencies in monitoring.
In light of these concerns, the FDA’s Centre for Drug Evaluation and Research has recommended the withdrawal of avacopan from the market. Similarly, the EMA’s Committee for Medicinal Products for Human Use (CHMP) has determined that the drug’s benefits no longer outweigh its risks and has advised its removal from the EU market, pending approval from the European Commission.
In Japan, Kissei Pharmaceutical, the entity marketing avacopan, suggested a temporary pause in new prescriptions yet later came to an agreement with regulators to maintain approval with strengthened safety warnings and routine liver function assessments.
The retraction of the trial report by the New England Journal of Medicine highlights discrepancies with appropriate research practices. Amgen has reiterated its dedication to scientific integrity and the peer-review mechanism. The company is conducting an independent assessment of the original trial data by the Duke Clinical Institute in the US and intends to present the findings at an FDA hearing by the end of July.