Cardiovascular · Clinical trials
Acute Coronary Syndrome Clinical Trials
Approved therapies, the pivotal-trial endpoints they were judged on, the magnitude of benefit — and the drugs that failed their endpoints, and why.
Indication overview
About acute coronary syndrome — and why its trials are hard
Acute coronary syndrome (ACS) spans unstable angina, non-ST-elevation myocardial infarction (NSTEMI) and ST-elevation myocardial infarction (STEMI), caused by acute coronary plaque rupture or erosion with thrombosis and abrupt reduction in myocardial blood flow. Management is time-critical, centered on rapid reperfusion (primary PCI for STEMI, early invasive strategy for high-risk NSTEMI), potent antithrombotic therapy and secondary prevention. Dual antiplatelet therapy (DAPT) with aspirin plus a P2Y12 inhibitor is foundational: ticagrelor demonstrated superiority to clopidogrel in PLATO, and prasugrel showed benefit in TRITON-TIMI 38 (at a cost of bleeding). Anticoagulation with heparin or bivalirudin supports the acute phase. High-intensity statins are initiated early, and post-ACS trials (IMPROVE-IT, ODYSSEY OUTCOMES) support aggressive LDL lowering with ezetimibe and PCSK9 inhibitors. The ACS antithrombotic field is defined by the ischemia-versus-bleeding tradeoff: several agents that reduced ischemic events, such as the PAR-1 antagonist vorapaxar and earlier oral factor inhibitors, caused excess bleeding that constrained or defeated their use, underscoring the narrow margin of intensified antithrombotic therapy.
Approved therapies & pivotal evidence
What's been approved — and by how much it moved the endpoint
| Drug (brand) | Approved | Setting | Pivotal trial | Primary endpoint | Magnitude of benefit |
|---|---|---|---|---|---|
| Ticagrelor (Brilinta/Brilique) | 2011 | DAPT with aspirin in ACS | PLATO | Composite of CV death, MI or stroke at 12 months | HR 0.84 (9.8% vs 11.7%) vs clopidogrel; reduced CV and all-cause mortality without increasing overall major bleeding |
| Prasugrel (Effient) | 2009 | DAPT with aspirin in ACS managed with PCI | TRITON-TIMI 38 | Composite of CV death, nonfatal MI or nonfatal stroke | HR 0.81 vs clopidogrel; ischemic benefit offset by increased major (including fatal) bleeding |
| Clopidogrel (Plavix) | 1997 | DAPT with aspirin in ACS | CURE | Composite of CV death, MI or stroke | ~20% relative risk reduction (HR ~0.80) vs aspirin alone in NSTE-ACS, with increased major bleeding |
| Alirocumab (Praluent) | 2015 | Lipid lowering after recent ACS | ODYSSEY OUTCOMES | Composite CHD death, nonfatal MI, ischemic stroke, unstable angina | HR 0.85 vs placebo on top of statin in patients 1-12 months post-ACS |
| Ezetimibe (Zetia) | 2002 | Add-on lipid lowering post-ACS | IMPROVE-IT | Composite CV death, MI, stroke, UA, revascularization | HR 0.936 added to simvastatin; first proof a non-statin LDL-lowering agent reduces post-ACS events |
Where trials have failed
Drugs that missed their endpoint — and what contributed
The most instructive lessons in acute coronary syndrome development come from programmes that failed the endpoint that mattered.
| Drug / trial | Endpoint outcome | What contributed |
|---|---|---|
| Vorapaxar — TRACER | Did not significantly reduce the broad primary composite in NSTE-ACS and increased major and intracranial bleeding | PAR-1 (thrombin receptor) antagonism added to standard antiplatelets produced excess bleeding, especially intracranial hemorrhage, offsetting ischemic benefit |
| Cangrelor — CHAMPION-PCI / CHAMPION-PLATFORM | Both initial trials missed their primary efficacy endpoints and were stopped/neutral | Endpoint definition of periprocedural MI was contentious; only later CHAMPION-PHOENIX with a revised endpoint succeeded, enabling approval |
| Otamixaban — TAO | Failed to reduce ischemic events versus heparin plus eptifibatide and increased bleeding in NSTE-ACS | Intravenous direct factor Xa inhibitor offered no efficacy advantage while raising bleeding, ending its development |
Choosing the right endpoint
Primary endpoints that matter in acute coronary syndrome trials
- Composite CV death, MI or stroke — Standard ischemic primary endpoint in ACS antiplatelet trials such as PLATO and TRITON-TIMI 38
- Major bleeding (TIMI/PLATO/GUSTO) — The counterbalancing safety endpoint; defines the net clinical benefit of intensified antithrombotics
- All-cause and CV mortality — Ticagrelor uniquely reduced mortality in PLATO, a key differentiator among P2Y12 inhibitors
- Net clinical benefit (efficacy vs bleeding) — Composite weighing ischemic prevention against bleeding harm; central to interpreting vorapaxar and prasugrel
How iNGENū runs acute coronary syndrome trials
Physician-led design, built for FDA submission
Endpoint & biomarker strategy
Board-certified specialists design endpoints and patient selection aligned to current FDA guidance for this indication.
FDA-ready data
Built to ICH-GCP and 21 CFR 312.120, with direct FDA submission — data accepted by the FDA, EMA and MHRA.
Faster, lower-cost delivery
~4-week ethics via the TGA CTN scheme, up to 43.5% R&D rebate, and 80–90% below US CRO cost.
Request a fixed-milestone proposal and a tailored endpoint & feasibility summary for this indication.
Frequently asked questions
Acute Coronary Syndrome clinical trials — FAQs
Which P2Y12 inhibitor is preferred after ACS?
Why did vorapaxar struggle in ACS?
How soon should lipid therapy start after ACS?
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