Cardiovascular · Clinical trials
Peripheral Artery Disease 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 peripheral artery disease — and why its trials are hard
Peripheral artery disease (PAD) is atherosclerotic narrowing of the arteries supplying the limbs, most often the legs, causing intermittent claudication, rest pain, impaired wound healing, and in advanced chronic limb-threatening ischemia, tissue loss and amputation. PAD is a marker of systemic atherosclerosis, so affected patients face elevated risk of myocardial infarction, stroke, and cardiovascular death alongside major adverse limb events. Management is built on aggressive risk-factor modification: high-intensity statins, smoking cessation, blood-pressure and glycemic control, and supervised exercise therapy for claudication. Antithrombotic therapy is central. Single antiplatelet therapy (aspirin or clopidogrel) is standard, while low-dose rivaroxaban added to aspirin (dual pathway inhibition) reduces both limb and cardiovascular events, validated in COMPASS and VOYAGER-PAD. Cilostazol improves walking distance for symptomatic claudication. Revascularization (endovascular or surgical) is reserved for lifestyle-limiting symptoms or limb threat. Drug therapy targets event prevention and symptom relief rather than reversing established atherosclerosis, and adherence to guideline-directed medical therapy remains persistently suboptimal in real-world PAD populations worldwide today.
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 |
|---|---|---|---|---|---|
| Rivaroxaban (low-dose 2.5 mg BID) plus aspirin (Xarelto) | 2018 (CAD/PAD indication); PAD post-revascularization added 2021 | Chronic symptomatic PAD; and after lower-extremity revascularization | COMPASS (NEJM 2017) and VOYAGER-PAD (NEJM 2020) | COMPASS: MACE composite; VOYAGER-PAD: composite of acute limb ischemia, major amputation of vascular etiology, MI, ischemic stroke, or CV death | VOYAGER-PAD: 3-year Kaplan-Meier event rate 17.3% vs 19.9% (HR 0.85, 95% CI 0.76-0.96, p=0.009); COMPASS PAD subgroup reduced MALE and MACE, with increased major bleeding |
| Cilostazol (Pletal) | 1999 | Symptomatic intermittent claudication (symptom relief) | Multiple placebo-controlled RCTs (pivotal registration trials) | Maximal and pain-free treadmill walking distance | Improved maximal walking distance by roughly 40-50% vs placebo; contraindicated in heart failure (PDE3 inhibitor class boxed warning) |
| Vorapaxar (Zontivity) | 2014 | Reduction of thrombotic CV events in patients with PAD or prior MI | TRA 2P-TIMI 50 (NEJM 2012) | Composite CV death, MI, or stroke | Reduced MACE (HR ~0.87) and reduced acute limb ischemia in the PAD subgroup, but increased moderate/severe bleeding including intracranial hemorrhage |
Where trials have failed
Drugs that missed their endpoint — and what contributed
The most instructive lessons in peripheral artery disease development come from programmes that failed the endpoint that mattered.
| Drug / trial | Endpoint outcome | What contributed |
|---|---|---|
| Ticagrelor — EUCLID (NEJM 2017) | Ticagrelor monotherapy was NOT superior to clopidogrel for the composite of CV death, MI, or ischemic stroke in symptomatic PAD (HR 1.02, p=0.65) | No incremental efficacy over clopidogrel with similar major bleeding; higher rate of dyspnea and study drug discontinuation, so it did not become a preferred PAD antiplatelet |
| Statin/ezetimibe and prostanoid limb-salvage agents (historical) — Various CLI prostanoid trials | Intravenous/oral prostanoids failed to consistently improve amputation-free survival in critical limb ischemia | Inconsistent efficacy, delivery/tolerability issues, and lack of durable limb-salvage benefit prevented broad regulatory adoption |
Choosing the right endpoint
Primary endpoints that matter in peripheral artery disease trials
- Major adverse limb events (MALE) — Acute limb ischemia and major amputation of vascular etiology; the limb-specific counterpart to MACE, key in VOYAGER-PAD
- MACE (CV death, MI, stroke) — Reflects PAD as systemic atherosclerosis; primary composite in COMPASS and vorapaxar/ticagrelor trials
- Maximal/pain-free walking distance — Treadmill-based functional endpoint for symptomatic claudication drugs such as cilostazol
- Amputation-free survival — Composite of survival free of major amputation; principal outcome in chronic limb-threatening ischemia trials
- Major bleeding — Key safety endpoint (ISTH/TIMI criteria) that offsets antithrombotic benefit in dual-pathway and PAR-1 antagonist regimens
How iNGENū runs peripheral artery disease 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
Peripheral Artery Disease clinical trials — FAQs
Is there a drug that reverses peripheral artery disease?
Why add low-dose rivaroxaban to aspirin?
Does cilostazol reduce heart attacks or death?
Ready to discuss your peripheral artery disease trial?
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