Avacopan (Tavneos), a first-in-class oral C5aR1 antagonist discovered at ChemoCentryx, faces an uncertain commercial future after the FDA requested the drug’s withdrawal from the market. The molecule was acquired by Amgen after ChemoCentryx’s $3.7 billion deal. The development raises the prospect of accelerated regulatory steps affecting supply, labeling, and future access for patients treated for ANCA-associated vasculitis. In the meantime, clinicians are likely to monitor for interim guidance and alternatives as regulatory review unfolds. The case will be read as a stress test for complement-framed immunomodulators at the post-approval stage, especially where benefit-risk decisions depend on evolving safety or efficacy evidence.