Amgen is seeking an independent review to defend Tavneos (avacopan) as the FDA weighs potential withdrawal of the rare disease drug. The dispute is tied to FDA concerns about safety and alleged manipulation of clinical trial data, framed against a backdrop of securities fraud litigation involving ChemoCentryx, the company that originally developed Tavneos. For Tavneos, the regulatory posture creates uncertainty around continued market access and the stability of commitments made by payers and providers. For other rare disease sponsors, the case is a reminder that post-approval compliance and data integrity controversies can translate into label-level consequences. Amgen’s next steps will likely center on addressing the FDA’s evidentiary concerns and presenting supporting analyses that can withstand scrutiny under formal regulatory review.