Bristol Myers Squibb and Johnson & Johnson halted one of three Phase III trials of milvexian, a selective factor XIa inhibitor, after an interim analysis showed futility for the acute coronary syndrome indication. The decision closes a major development path aimed at delivering a next‑generation anticoagulant with potentially improved bleeding safety. Milvexian’s failure in the acute coronary syndrome trial is the latest setback for factor XIa programs seeking to displace existing anticoagulants. The result raises questions about the molecule’s efficacy in high‑intensity ischemic settings and will pressure developers to reassess other ongoing indications and trial designs. The outcome underscores clinical risk in advancing novel anticoagulants into broad cardiovascular indications. For BMS and J&J, the stoppage will force reprioritization of resources and may impact partner and investor confidence in the class until other studies report.