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Milvexian with Antiplatelet Therapy after Acute Coronary Syndrome Event
Key result
Milvexian shows no benefit over placebo for major cardiovascular events after recent ACS.
- HR 1.05
- 95% CI 0.91-1.21
- P=0.50
- n=14,194
Why the trial?
Adding an anticoagulant to antiplatelet therapy after acute coronary syndrome reduces ischaemic events but has been limited by bleeding. Factor XIa inhibition promises antithrombotic protection with less bleeding, and LIBREXIA ACS asked whether milvexian delivers that benefit after a recent ACS.
Does milvexian reduce the risk of cardiovascular death, myocardial infarction, or ischemic stroke in patients with a recent acute coronary syndrome event?
Population
14,194 patients within 7 days of an acute coronary syndrome event
Comparison
Milvexian 25 mg twice daily vs matched placebo, added to standard antiplatelets
Design
Phase 3 randomized placebo-controlled trial; terminated early for futility
Follow-up
Median 12.2 months
Authors
Discussion
Key questions
No takes yet. Share an insight, caveat, or question.
Where experts stand
Experts uniformly read LIBREXIA ACS as a clear null result for factor XIa inhibition after ACS, with no one arguing the finding is practice-changing, though some note the mechanism may still hold promise in other settings.
Clinicians agree that milvexian failed to reduce ischemic events on top of antiplatelet therapy and that the trial was appropriately stopped for futility. The safety profile was reassuring, with no increase in serious bleeding, but that is not enough to salvage the efficacy story in ACS. The live question is whether higher doses or different patient populations (such as atrial fibrillation or secondary stroke prevention) can still vindicate factor XIa inhibition as a therapeutic strategy.
Agreement
Multiple clinicians emphasize that milvexian was safe, with no increase in serious bleeding, but delivered no efficacy benefit in the post-ACS setting. They describe a clear null result and note the trial was stopped early for futility.
5 clinicians say this directly
What they’re arguing about
supportiveneutralcautiouscritical
Counts are expert takes we classified by axis. Tap a row to see the takes behind its count.
Still unclear
Whether factor XIa inhibition will prove effective at higher doses or in different populations remains open. Ongoing milvexian trials in atrial fibrillation and secondary stroke prevention use a different dose and different background therapy, and experts have not yet weighed in on how much this ACS failure should temper expectations for those programs.
Key expert perspectives
Patients stay at high ischemic risk after ACS and factor XIa inhibition did not close that gap
Damluji contextualizes the trial by noting that recurrent ischemic risk persists despite dual antiplatelet therapy, high-intensity statins, and current-generation stents. He shared a clinical-practice summary of the null result and its market implications for factor XIa inhibitors.
The factor XIa hypothesis did not deliver efficacy in this setting
Gouda framed the trial's rationale as testing whether factor XIa inhibition could add efficacy without more bleeding after ACS. After results, he concluded directly that the factor XIa hypothesis did not deliver efficacy here, citing the HR of 1.05 with a median exposure of 10 months.
The factor XIa hypothesis falls short after ACS but the unmet need remains
Galluzzo frames the result as a definitive failure of the factor XIa hypothesis in the ACS setting. Milvexian added to antiplatelet therapy did not reduce CV death, MI, or ischaemic stroke and did not increase BARC 3c/5 bleeding. He highlights that the unmet need for residual risk reduction after ACS persists.
Distilled from their postX post
Implication
Milvexian adds no ischemic benefit after ACS; safety supports continued evaluation in ongoing atrial fibrillation and stroke prevention trials.
Key Points
- To evaluate the efficacy and safety of adding the oral factor XIa inhibitor milvexian to standard antiplatelet therapy in patients with a recent acute coronary syndrome event.
- Phase 3, randomized, placebo-controlled trial (NCT05754957) enrolling 14,194 patients within 7 days after an acute coronary syndrome event.
- Patients were assigned in a 1:1 ratio to receive oral milvexian (25 mg twice daily, n=7,094) or matched placebo (n=7,100) on top of standard antiplatelet therapy, with a median follow-up of 12.2 months.
- The primary efficacy outcome (cardiovascular death, myocardial infarction, or ischemic stroke) occurred in 384 patients (5.4%) in the milvexian group and 365 patients (5.1%) in the placebo group (HR, 1.05; 95% CI, 0.91 to 1.21; P=0.50), leading to early trial termination for futility.
- Principal safety endpoint of BARC type 3c or 5 bleeding occurred in 23 patients (0.3%) in the milvexian group and 22 patients (0.3%) in the placebo group (P=0.88).
Evidence details
What drove the result?
| Outcome | Milvexian | Placebo |
|---|---|---|
| CV death, MI, or ischemic stroke | 384 (5.4%) | 365 (5.1%) |
| HR 1.05 (95% CI 0.91-1.21); P=0.50 - trial stopped for futility at interim | ||
Limitations & tradeoffs
Safety
BARC 3c or 5 bleeding (intracranial/fatal) 23/7094 (0.3%) vs 22/7100 (0.3%); P=0.88.
Statistical certainty
terminated for futility at a planned interim based on 556 adjudicated events.
Design limitations
median follow-up of 12.2 months is relatively short, and only one dose (25 mg twice daily) was evaluated.
Structured PICO
Does milvexian reduce the risk of cardiovascular death, myocardial infarction, or ischemic stroke in patients with a recent acute coronary syndrome event?
P
Population
14,194 patients with a recent acute coronary syndrome event, followed for a median of 12.2 months.
I
Intervention
Oral milvexian (25 mg twice daily) added to standard antiplatelet therapy
C
Comparator
Matched placebo added to standard antiplatelet therapy
O
Outcome
Composite of cardiovascular death, myocardial infarction, or ischemic stroke as evaluated in a time-to-event analysiscomposite
Main Result
Hazard Ratio: 1.05 (95% CI 0.91–1.21)
Absolute Event Rate: 5.4% vs 5.1%
p-value: p=0.50
In patients with recent acute coronary syndrome, adding the factor XIa inhibitor milvexian to standard antiplatelet therapy did not reduce ischemic events, leading to early termination for futility.
Coverage & sources
Journal, society, and media accounts. Useful signal, not independent expert judgment.
Cite This Study
Gibson et al. (2026) conducted an RCT in Acute coronary syndrome (n=14,194). Milvexian vs. Placebo was evaluated on Composite of cardiovascular death, myocardial infarction, or ischemic stroke (HR 1.05, 95% CI 0.91-1.21, p=0.50). Milvexian added to standard antiplatelet therapy did not decrease the risk of cardiovascular death, myocardial infarction, or ischemic stroke compared with placebo (HR 1.05; 95% CI 0.91-1.21; P=0.50).