Granulocyte-Macrophage Stimulating Factor (GM-CSF) in Peripheral Arterial Disease

Granulocyte-Macrophage Stimulating Factor (GM-CSF) in Peripheral Arterial Disease: The GPAD-3 Study

Granulocyte-Macrophage Stimulating Factor (GM-CSF) in Peripheral Arterial Disease (NCT03304821) is a Phase 2 interventional studying Peripheral Artery Disease (PAD), sponsored by Emory University. RECRUITING as of the most recent ClinicalTrials.gov update. Talk to your doctor before contacting the trial site.

About This Trial

Peripheral artery disease (PAD) is a disease in which plaque builds up in the arteries that carry blood to the head, organs, and limbs. PAD usually occurs in the arteries in the legs, but can affect any arteries. Over time, plaque can harden and narrow the arteries which limits the flow of oxygen-rich blood to organs and other parts of the body. Blocked blood flow to the arteries can cause pain and numbness. The pain is usually worse with exercise and gets better with rest. PAD can raise the risk of getting an infection which could lead to tissue death and amputation. This study is investigating whether granulocyte-macrophage colony stimulating factor (GM-CSF) improves symptoms and blood flow in people with PAD. GM-CSF is a drug that is used to stimulate the bone marrow to release stem cells. Participants in the study will be randomly selected to receive GM-CSF or a placebo. After a four-week screening phase, participants will receive injections of GM-CSF or a placebo three times a week for three-weeks. Three months later, participants will again receive injections of GM-CSF or placebo three times a week for three-weeks. At six months, the study team will follow up to see if the group that received GM-CSF had more improvement than the group that received placebo.

What Stage of Research Is This?

Phase 2 trials evaluate whether a treatment actually works against Peripheral Artery Disease (PAD) and continue monitoring side effects. Phase 2 enrolls larger groups (typically 100–300 patients) and produces the first real efficacy signal. A successful Phase 2 readout is what unlocks the much larger Phase 3 confirmatory trials needed for FDA 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 176 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 (PAD) 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: - Female subjects must be (a) post-menopausal, (b) surgically sterile or (c) use adequate birth control and have a negative pregnancy test within 3 days prior to administration of study drug and should not be breastfeeding. - Documented symptomatic PAD - Clinically stable (at least 2 months prior to enrollment) history of intermittent claudication or walking impairment (Rutherford Class II) with no change in symptom severity in the 2 months prior to screening. - On statin therapy for previous 3 months prior to enrollment, unless statin intolerant. - Peak Walking Time (PWT) between 1 and 12 minutes on a standardized Gardner treadmill protocol or modified Gardner protocol or less than 12 minutes on a modified Bruce protocol in case PWT on Gardner protocol is more than 12 minutes. - A Doppler-derived ankle-brachial index (ABI) of \< 0.90 in the symptomatic limb after 10 minutes of rest at screening. For subjects with an ABI of \>1.3 (non-compressible arteries) a Toe-Brachial Index (TBI) of \< 0.70 must be obtained for subject qualification, or if ABI is \> 0.9 to 1.0 , and a reduction of 20% in ABI measured within 1 minute of treadmill testing. - On appropriate and stable medical therapy for atherosclerosis for at least 2 months prior to enrollment. - Able to give willing to sign a consent form. - Diabetics with a dilated eye exam excluding proliferative retinopathy in the previous 12 months prior to enrollment. Who Should NOT Join This Trial: - Recent or current active infections (treated with antibiotics) - Recent (6 months prior to randomization) or current active cancer undergoing treatment - Recent (3 months prior to randomization) change in statin or cilostazol therapy - Critical limb ischemia either chronic (Rutherford Class \>II) or acute ischemia manifested by rest pain, ulceration, or gangrene - Recent (3 months prior to randomization) lower extremity vascular surgery, angioplasty or lumbar sympathectomy ...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: * Female subjects must be (a) post-menopausal, (b) surgically sterile or (c) use adequate birth control and have a negative pregnancy test within 3 days prior to administration of study drug and should not be breastfeeding. * Documented symptomatic PAD * Clinically stable (at least 2 months prior to enrollment) history of intermittent claudication or walking impairment (Rutherford Class II) with no change in symptom severity in the 2 months prior to screening. * On statin therapy for previous 3 months prior to enrollment, unless statin intolerant. * Peak Walking Time (PWT) between 1 and 12 minutes on a standardized Gardner treadmill protocol or modified Gardner protocol or less than 12 minutes on a modified Bruce protocol in case PWT on Gardner protocol is more than 12 minutes. * A Doppler-derived ankle-brachial index (ABI) of \< 0.90 in the symptomatic limb after 10 minutes of rest at screening. For subjects with an ABI of \>1.3 (non-compressible arteries) a Toe-Brachial Index (TBI) of \< 0.70 must be obtained for subject qualification, or if ABI is \> 0.9 to 1.0 , and a reduction of 20% in ABI measured within 1 minute of treadmill testing. * On appropriate and stable medical therapy for atherosclerosis for at least 2 months prior to enrollment. * Able to give informed consent. * Diabetics with a dilated eye exam excluding proliferative retinopathy in the previous 12 months prior to enrollment. Exclusion Criteria: * Recent or current active infections (treated with antibiotics) * Recent (6 months prior to randomization) or current active cancer undergoing treatment * Recent (3 months prior to randomization) change in statin or cilostazol therapy * Critical limb ischemia either chronic (Rutherford Class \>II) or acute ischemia manifested by rest pain, ulceration, or gangrene * Recent (3 months prior to randomization) lower extremity vascular surgery, angioplasty or lumbar sympathectomy * Planned participation in a structured exercise treatment protocol in the future or within period of study * Prior myeloid malignancy * Recent (3 months prior to randomization) Unstable angina, myocardial infarction, transient ischemic attack (TIA), stroke or revascularization * Severe heart failure (Class III or IV) or heart muscle disease * Limitation on exercise for symptoms other than intermittent claudication such as arthritis or dyspnea * Below- or above-knee amputation; wheelchair confinement * Use of a walking aid other than a cane * Walking impairment for reasons other than PAD e.g. Parkinson's disease * Uncontrolled diabetes mellitus (defined as HbA1c \> 10.0) * Chronic renal disease (creatinine of \>2.5 mg/dl) or hepatic disease (\> 3 X elevations in aspartate aminotransferase (AST) and alanine aminotransferase (ALT)) * White blood cell count \< 3k/cmm * Hemoglobin (HGB) \< 10g/dL * Blood Pressure Systolic \>180 and/or Diastolic \>100 * Taking Immunosuppressant drugs * Ophthalmologic conditions associated with a neo-vascular response * Alcohol or drug abuse, or any other disease process that, in the opinion of the PI, will interfere with the ability of the patient to participate in the study * Inability to attend study visits

Treatments Being Tested

DRUG

GM-CSF

Participants will self-administer 500 μg/day of GM-CSF, subcutaneously, three times per week (Monday, Wednesday, Friday) for three weeks. After three months the participants will receive a second administration of 500 μg/day of subcutaneous GM-CSF, three times per week for another 3 weeks and then will be followed for another 3 months.

DRUG

Placebo

Participants will self-administer 500 μg/day of a placebo, subcutaneously, three times per week (Monday, Wednesday, Friday) for three weeks. After three months the participants will receive a second administration of 500 μg/day of a placebo administered subcutaneously, three times per week for another 3 weeks and then will be followed for another 3 months.

Locations (1)

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.

Emory University Hospital

Atlanta, Georgia, United States

How to Talk to Your Doctor About This Trial

Bring the printable summary of this trial — including the NCT ID (NCT03304821), the sponsor (Emory 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 NCT03304821 clinical trial studying?

Who can participate in NCT03304821?

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 NCT03304821?

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 NCT03304821. Maintained by the National Library of Medicine at NIH. Public domain. Cite as: "TrialFinderData. NCT03304821. 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.