Bristol Myers Squibb & Johnson & Johnson Halt Phase 3 Librexia ACS Trial After Interim Review

Bristol Myers Squibb & Johnson & Johnson Halt Phase 3 Librexia ACS Trial After Interim Review

By, Admin 17 November 2025

Bristol Myers Squibb (BMS) and Johnson & Johnson have jointly decided to stop the Phase 3 Librexia ACS trial, which evaluated milvexian—an investigational Factor XIa inhibitor—as an add-on therapy to standard antiplatelet treatment for patients recovering from acute coronary syndrome (ACS).

The decision follows a pre-planned interim analysis by the Independent Data Monitoring Committee (IDMC). The committee concluded the trial was unlikely to meet its primary efficacy endpoint, prompting sponsors to discontinue the study.

No New Safety Issues Identified

Despite the lack of efficacy in this ACS setting, the IDMC confirmed:

  • No new safety concerns related to milvexian
  • A safety profile consistent with earlier Phase 2 findings

This allows other ongoing trials in the Librexia program to continue without changes.

What Happens to the Other Librexia Trials?

The Librexia program includes three major Phase 3 studies:

1. Librexia AF (Atrial Fibrillation)

  • Evaluates milvexian vs. apixaban
  • Focuses on preventing stroke and systemic embolism
  • Continues as planned
  • Topline data expected in 2026

2. Librexia STROKE (Secondary Stroke Prevention)

  • Tests milvexian in addition to antiplatelet therapy
  • Targets patients with recent ischemic stroke or high-risk TIA
  • Continues as scheduled
  • Results also expected in 2026

3. Librexia ACS (Acute Coronary Syndrome)

  • The discontinued study
  • Aimed to measure reductions in major adverse cardiovascular events (MACE)
  • Interim review showed efficacy unlikely to be achieved

Why This Matters: The Challenge of Treating ACS

ACS remains one of the world’s most pressing cardiovascular emergencies:

  • 7+ million people diagnosed globally each year
  • Risk of recurrent events remains >5% in the first year
  • Combining anticoagulants with antiplatelets is often avoided due to bleeding risk

Milvexian—if successful—could offer a safer, next-generation anticoagulant option.
Although the ACS trial fell short, experts still see promise in its mechanism.

Scientific Leaders Affirm Confidence in Milvexian

BMS Perspective

Dr. Roland Chen of Bristol Myers Squibb emphasized strong confidence in the AF and SSP programs:

Milvexian still has the potential to redefine anticoagulation without significantly increasing bleeding risk.

He noted key differences between the ACS study and the ongoing trials, including patient types, endpoints, disease pathology, and background therapies.

Academic Perspective

Dr. Robert A. Harrington of Weill Cornell Medicine highlighted:

Treating ACS is complex, but the absence of new safety issues supports continued exploration of FXIa inhibition.

About Milvexian

Milvexian is:

  • An oral, highly selective Factor XIa inhibitor
  • Designed to prevent harmful clotting while preserving normal clotting (haemostasis)
  • Part of one of the largest FXIa development programs to date
  • Still investigational and not approved in any country

If successful, it may advance treatment for a broad range of thrombotic conditions.

Inside the Librexia Phase 3 Program

The Librexia programme, led by Johnson & Johnson with BMS, covers 50,000+ patients across three major trials.

1. Librexia ACS (Discontinued)

  • Adults ≥18 years within 7 days of ACS
  • On antiplatelet therapy
  • Primary endpoint: MACE reduction
  • Reason for halt: Low likelihood of achieving endpoint

2. Librexia AF

  • Adults ≥18 with atrial fibrillation
  • Compares milvexian to apixaban
  • Primary endpoint: stroke + systemic embolism

3. Librexia STROKE

  • Adults ≥40 with recent ischemic stroke or high-risk TIA
  • Adding milvexian to antiplatelet therapy
  • Primary endpoint: time to ischemic stroke

Commitment to Advancing Thrombosis Research

Both BMS and Johnson & Johnson reaffirm their goal to:

  • Address unmet needs in thrombosis
  • Overcome limitations of current therapies
  • Advance FXIa inhibitors as safer anticoagulant options

Bristol Myers Squibb reiterated its mission to develop innovative medicines that help patients overcome serious diseases.

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