Amgen moved to defend Tavneos after the FDA signaled possible withdrawal, according to MedCity News. The rare-disease drug, developed by ChemoCentryx and approved for treating a form of vasculitis, is facing heightened scrutiny tied to allegations that trial data were manipulated, with FDA concerns framed around potential safety risks. Amgen says it has asked for an independent review, aiming to establish that the evidence supports continued approval. The dispute centers on how regulators assess integrity of clinical-trial materials and what remediation or additional review is required when fraud-related litigation intersects with regulatory decision-making. For biotech investors and developers, the case is a reminder that post-approval oversight can accelerate when external legal action and regulator concerns converge—creating a direct path to label changes, additional submissions, or withdrawal processes.