The FDA has proposed withdrawing Amgen’s Tavneos (avacopan), alleging “untrue statements” were included in the approval application for the C5a receptor antagonist. The notice would unwind the regulatory basis for the drug’s approval unless resolved through subsequent processes. The action arrives after earlier FDA scrutiny of trial data and compounds uncertainty for clinicians managing patients with vasculitis who rely on an approved option. Amgen’s 2022 acquisition of Chemocentryx placed Tavneos at the center of the company’s rare autoimmune strategy. For Amgen and the broader market, the dispute highlights ongoing risk around data integrity during approval and post-approval surveillance—particularly when regulator claims point to materially altered submissions.