SDF1 Plasmid Treatment for Patients With Peripheral Artery Disease

Major Inclusion Criteria: * Age ≥18 * Currently receiving standard of care wound treatment (\>2 weeks) for chronic wounds or gangrene including as indicated: debridement, pressure offloading, infection control, and/or maintenance of a moist wound environment. * Diagnosis of advanced PAD with tissue loss (ulceration and/or dry gangrene) on the foot of the index leg with an ulcer size of at least 0.5 cm2 and \<25 cm2. Index wounds on the heel must be \<10 cm2 that cannot be probed to bone, have exposed bone or osteomyelitis. * Post revascularization intervention inclusion criteria include an attempt at open bypass grafting or endovascular intervention of a popliteal/infrapopliteal lesion(s) on the same leg that has tissue loss without significant improvement in TBI post intervention. The following will be accepted as demonstrating a lack of post intervention toe brachial index (TBI) improvement: * TBI ≤ 0.51or; * Toe pressure ≤50 mmHg with flat or dampened wave forms or; * Skin Perfusion pressure ≤40 mmHg at mid foot level or; * TcPO2 ≤40 mmHg * Subjects willing to forgo treatment with hyperbaric oxygen, nerve stimulation or sympathectomy for the treatment of advanced PAD from time of consent to 6 months following the initial injection of study drug Major Exclusion Criteria: * Previous major amputation of the leg to be treated or planned major amputation or transmetatarsal amputation within the first month following enrollment. * Only a short segment superficial femoral artery lesion - consistent with Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC II) A or B category, and no infrapopliteal disease * Staged or planned intervention in the index leg within 30 days after the index procedure * Acute limb-threatening ischemia, trauma, known non-atherosclerotic vascular disease * Non-salvageable limb defined as major tissue loss and an unsalvageable foot; * Wounds that have decreased in size by \>50% between the Screening visit and Day 0. * If patient has active infection of the index limb that is being treated, and, in the opinion of treating physician, will not lead to an amputation within the next 3 months, the patient can be enrolled. * Inability to safely perform a revascularization procedure due to uncontrolled diabetes or other medical condition. * Presence of any other condition that, in the opinion of the investigator, might compromise any aspect of the trial