The FDA has asked Amgen to withdraw Tavneos (avacopan) from the US market while revisiting data‑adjudication issues from the drug’s pivotal trial; Amgen has publicly refused and said it will engage with the agency. BioCentury reporting flagged interpretation of primary endpoint re‑adjudication and past trial data handling as drivers of the FDA’s request. The standoff creates immediate commercial uncertainty for a previously approved complement inhibitor and underscores intensifying regulatory scrutiny of trial‑level data integrity.