The COCOA-PAD II Trial

COCOA Flavanols to Improve Walking Performance in PAD: the COCOA-PAD II Trial

The COCOA-PAD II Trial (NCT04794530) is a Phase 3 interventional studying Peripheral Artery Disease, sponsored by Northwestern University. RECRUITING as of the most recent ClinicalTrials.gov update. Talk to your doctor before contacting the trial site.

About This Trial

Among people with peripheral artery disease (PAD) age 55 and older, the investigators will test the hypothesis that PAD participants randomized to cocoa flavanols will have greater improvement or less decline in six-minute walk distance at six-month follow-up, compared to those randomized to placebo. The study will randomize 190 participants with PAD age 55 and older to one of two groups for six months: cocoa flavanols vs placebo. Our primary outcome is change in six-minute walk distance at six-month follow-up. Secondary outcomes are Actigraph-measured physical activity, brachial artery flow-mediated dilation (FMD), gastrocnemius muscle biopsy measures of endothelial nitric oxide synthase (eNOS) and phosphorylated eNOS, gastrocnemius muscle perfusion (measured by magnetic resonance imaging (MRI)) and gastrocnemius muscle characteristics (measured by muscle biopsy). To achieve the specific aims, the study will randomize 190 participants age 55 and older with PAD to one of two groups: cocoa flavanols vs placebo. Participants will be followed for six months.

What Stage of Research Is This?

Phase 3 trials confirm efficacy and safety in large patient groups (often 300–3,000+) and form the evidence base for an FDA approval submission. For Peripheral Artery Disease, Phase 3 studies typically randomize participants between the investigational treatment and either a placebo or current standard of care. A successful Phase 3 result is the threshold most treatments need to clear before regulatory approval.

This trial is currently recruiting participants. The sponsor has registered the study with ClinicalTrials.gov as actively enrolling, which means new applicants who meet the eligibility criteria can be considered for screening. Trial status can change between updates — confirm current recruiting status with the study contact before traveling for a screening visit.

Target enrollment of 190 participants puts this in the typical range for a Phase 2-style efficacy study or a moderate Phase 3 trial in a focused Peripheral Artery Disease subpopulation. At this scale, the study has enough statistical power to detect a clear treatment effect but is not the largest cohort in the field.

Who May Be Eligible (Plain English)

Who May Qualify: 1. Age 55 and older 2. Presence of peripheral artery disease (PAD). PAD will be defined as either: 1. An ABI \<= 0.90 at baseline. 2. Vascular lab evidence of PAD (such as a toe brachial pressure \< 0.70 or an ankle brachial index less than or equal to 0.90), or angiographic evidence of PAD defined as at least 70% stenosis of an artery supplying the lower extremities. 3. An ABI of \>0.90 and \<=1.00 who experience a a 20% or greater drop in ABI in either leg after the heel-rise test will also be included. Who Should NOT Join This Trial: 1. Above- or below-knee amputation 2. Critical limb ischemia 3. Wheelchair confinement or requiring a walker to ambulate 4. Walking is limited by a symptom other than PAD 5. Current foot ulcer on bottom of foot 6. Failure to successfully complete the one-week study run-in 7. Planned major surgery, coronary or leg revascularization during the next eight months 8. Major surgery, coronary or leg revascularization or major cardiovascular event in the previous three months 9. Major medical illness including lung disease requiring oxygen, Parkinson's disease, a life-threatening illness with life expectancy less than eight months, or cancer requiring treatment in the previous two years. \[NOTE: potential participants may still qualify if they have had treatment for an early stage cancer in the past two years and the prognosis is excellent. Participants who require oxygen only at night may still qualify.\] 10. Mini-Mental Status Examination (MMSE) score \< 23 11. Allergy to the study intervention 12. Potential participants who have taken cocoa supplements in previous three months, are unwilling to avoid taking cocoa flavanol supplements, or are consuming dark chocolate regularly (i.e. approximately 1.5 ounces of dark chocolate more than three times per week, or more than 4.5 ounces per week). 13. Non-English speaking ...See full criteria on ClinicalTrials.gov Always talk to your doctor about whether this trial is right for you.

These are translations of the protocol\'s inclusion and exclusion criteria, simplified for patients and caregivers. The original clinical text appears below. Eligibility is ultimately confirmed by the trial site\'s screening process — this summary is a starting point for a conversation with your doctor, not a final determination.

Original Eligibility Criteria

View original clinical language

Inclusion Criteria: 1. Age 55 and older 2. Presence of peripheral artery disease (PAD). PAD will be defined as either: 1. An ABI \<= 0.90 at baseline. 2. Vascular lab evidence of PAD (such as a toe brachial pressure \< 0.70 or an ankle brachial index less than or equal to 0.90), or angiographic evidence of PAD defined as at least 70% stenosis of an artery supplying the lower extremities. 3. An ABI of \>0.90 and \<=1.00 who experience a a 20% or greater drop in ABI in either leg after the heel-rise test will also be included. Exclusion Criteria: 1. Above- or below-knee amputation 2. Critical limb ischemia 3. Wheelchair confinement or requiring a walker to ambulate 4. Walking is limited by a symptom other than PAD 5. Current foot ulcer on bottom of foot 6. Failure to successfully complete the one-week study run-in 7. Planned major surgery, coronary or leg revascularization during the next eight months 8. Major surgery, coronary or leg revascularization or major cardiovascular event in the previous three months 9. Major medical illness including lung disease requiring oxygen, Parkinson's disease, a life-threatening illness with life expectancy less than eight months, or cancer requiring treatment in the previous two years. \[NOTE: potential participants may still qualify if they have had treatment for an early stage cancer in the past two years and the prognosis is excellent. Participants who require oxygen only at night may still qualify.\] 10. Mini-Mental Status Examination (MMSE) score \< 23 11. Allergy to the study intervention 12. Potential participants who have taken cocoa supplements in previous three months, are unwilling to avoid taking cocoa flavanol supplements, or are consuming dark chocolate regularly (i.e. approximately 1.5 ounces of dark chocolate more than three times per week, or more than 4.5 ounces per week). 13. Non-English speaking 14. Participation in or completion of a clinical trial in the previous three months. \[NOTE: after completing a stem cell or gene therapy intervention, participants will become eligible after the final study follow-up visit of the stem cell or gene therapy study so long as at least six months have passed since the final intervention administration. After completing a supplement or drug therapy (other than stem cell or gene therapy), participants will be eligible after the final study follow-up visit as long as at least three months have passed since the final intervention of the trial.\] 15. Visual impairment that limits walking ability 16. Six-minute walk distance of \<500 feet or \>1600 feet. 17. Participation in a supervised treadmill exercise program in previous three months 18. Unable to tolerate caffeine 19. In addition to the above criteria, investigator discretion will be used to determine if the trial is unsafe or not a good fit for the potential participant

Treatments Being Tested

DRUG

cocoa flavanols

The cocoa flavanols intervention is manufactured by Mars Inc. Participants randomized to cocoa flavanols will take two capsules daily of cocoa flavanols. The two capsules of cocoa flavanols will contain approximately 500 mg of cocoa flavanols and appoximately 80 mg of (-)-epicatechin.

DRUG

placebo

The placebo intervention will be manufactured by Mars Inc. and will appear identical to the cocoa flavanols intervention. Participants will take two capsules daily of placebo. The placebo will be a cellulose based capsule and will not contain cocoa flavanols or (-)-epicatechin.

Locations (3)

Trial sites listed on ClinicalTrials.gov for this study. Site activation status can vary — confirm with the specific site before traveling for a screening visit.

Northwestern University

Chicago, Illinois, United States

University of Chicago

Chicago, Illinois, United States

University of Minnesota

Minneapolis, Minnesota, United States

How to Talk to Your Doctor About This Trial

Bring the printable summary of this trial — including the NCT ID (NCT04794530), the sponsor (Northwestern University), and the key eligibility criteria — to your next appointment. Your doctor can review the inclusion and exclusion criteria against your medical history, lab values, and current treatments to assess whether you are likely to qualify. They can also help you weigh whether trial participation makes sense alongside your existing care plan.

Useful questions to walk through together: What does the trial protocol require beyond standard care? How long is the active treatment phase, and how long is follow-up? Are there study visits at sites I can reach? Who pays for the trial-specific procedures, and who pays for standard-of-care portions? See our 25 questions to ask about clinical trials guide for a more complete checklist.

Authoritative Sources

The official record for this trial lives on ClinicalTrials.gov — the federal registry maintained by the National Library of Medicine at NIH. For background on how this trial fits into the FDA approval pathway, see the FDA drug approval process. For oncology-specific guidance for patients considering trials, the National Cancer Institute publishes patient-oriented overviews. International trial registries are aggregated by the WHO ICTRP.

Frequently Asked Questions

What is the NCT04794530 clinical trial studying?

Who can participate in NCT04794530?

Eligibility for this trial depends on the specific inclusion and exclusion criteria set by the sponsor. The plain-English summary above translates the most important criteria into accessible language; the official clinical text is preserved in the collapsible section underneath. Whether you fit any specific trial is a medical decision your doctor needs to confirm — bring the trial information to your treating physician for a full review against your medical history.

How do I contact the trial site for NCT04794530?

Contact information registered with ClinicalTrials.gov is shown in the sidebar of this page. Before reaching out, confirm with your treating physician that this trial is appropriate for your situation. The trial site will then walk you through the screening process to determine final eligibility.

Is participating in a clinical trial safe?

Clinical trials in the United States are regulated by the FDA and overseen by Institutional Review Boards (IRBs) that review the protocol for safety. Risk varies by trial — Phase 1 studies test new treatments in humans for the first time, while Phase 3 trials use treatments that have already passed earlier safety screening. The informed consent document for any specific trial details the known risks and what to expect. Discuss those risks with your physician before deciding whether to participate.

Where can I verify the data on this page?

Every detail on this page comes directly from the ClinicalTrials.gov API. Click "View on ClinicalTrials.gov" in the sidebar to see the official, unmodified record. The federal record is always authoritative; this page is a structured presentation with a plain-English eligibility translation. For background on how clinical trials are regulated, see the FDA drug approval process documentation.

How This Page Is Built

Every field on this page is pulled directly from the ClinicalTrials.gov API v2 — no estimates, no proxies. The plain-English eligibility translation is generated from the original protocol text and reviewed for fidelity to the underlying clinical criteria. The original clinical text remains visible in the collapsible section above so users and clinicians can verify the translation. Read the full methodology for the data pipeline and known limitations.

Source: ClinicalTrials.gov API v2 record for NCT04794530. Maintained by the National Library of Medicine at NIH. Public domain. Cite as: "TrialFinderData. NCT04794530. Data: ClinicalTrials.gov."

Medical disclaimer: This page is informational, not medical advice. Talk to your doctor about whether a clinical trial is right for you.

Last updated 2026-05-08 · Data from ClinicalTrials.gov.