Bristol Myers Squibb and Johnson & Johnson Face Setback in Anticoagulant Development

Bristol Myers Squibb (BMS) and Johnson & Johnson (J&J) have announced the discontinuation of a pivotal Phase III trial for their investigational anticoagulant milvexian in acute coronary syndrome (ACS), marking a significant setback in the development of next-generation blood thinners.

Milvexian Trial Halted Early

The Librexia ACS trial, which was studying the oral factor XIa inhibitor milvexian for treating ACS, has been stopped prematurely after a preplanned interim analysis revealed the drug was unlikely to meet its primary endpoint. The study, designed to enroll 16,000 patients, was evaluating milvexian's efficacy in preventing major adverse cardiovascular events when added to standard antiplatelet therapies.

Robert A. Harrington, dean of Weill Cornell Medicine and Librexia program chair, commented on the findings, stating they "confirmed the complexity of treating ACS and the need to further advance knowledge of the disease."

Implications for BMS and J&J

The failure in ACS represents a significant blow to BMS and J&J's ambitions for milvexian, which was being developed as a potentially safer alternative to widely used anticoagulants like Eliquis and Xarelto. The setback has immediate financial implications, with BMS shares dropping 3.4% to approximately $47 in Friday morning trading.

Despite this setback, the companies remain committed to the development of milvexian in other indications. Two other Phase III trials testing the molecule in atrial fibrillation and secondary stroke prevention are continuing, with topline data expected in 2026. These ongoing studies represent substantial market opportunities, with BMS previously estimating the addressable patient population for secondary stroke prevention at approximately 1.3 million across the US and EU, and an even larger potential in atrial fibrillation with around 14 million patients.

Broader Industry Impact

The failure of milvexian in ACS adds to a series of setbacks for factor XIa inhibitors, a class of drugs that has attracted significant interest from pharmaceutical companies. This development may have implications for other companies pursuing similar therapies, including Novartis and Regeneron, which have invested heavily in this area.

For BMS, this represents another recent negative readout in a year that has seen late-stage stumbles across various therapeutic areas, including cancer and mental health conditions. The company is particularly keen on finding a successor to Eliquis, its best-selling drug, which is facing patent expiration.

While the ACS market opportunity is now likely closed for milvexian, BMS and J&J continue to view the drug as having "multibillion-dollar potential" based on its ongoing trials in atrial fibrillation and stroke prevention. The pharmaceutical industry will be closely watching the results of these studies, expected in 2026, to gauge the future of factor XIa inhibitors in anticoagulation therapy.