The FDA proposed withdrawing Amgen’s Tavneos, alleging “untrue statements of material fact” in the approval application for avacopan. The action would target a C5aR antagonist approved in 2021 after Amgen’s buyout of ChemoCentryx for about $3.7 billion. The proposal extends a pattern of heightened regulator scrutiny over the evidentiary record supporting approvals, particularly when post-approval analyses raise questions about trial conduct or data integrity. Amgen has not indicated acceptance of the agency’s position in the reporting. For the immunology market, any final withdrawal would reverberate through payer coverage decisions and could force providers to transition patients off a currently approved option.