In 2010, we completed a phase 1 to 2a clinical trial of pCMV-vegf165 in patients with chronic lower limb ischemia (stage 2a to 3 according to Fontaine classification modified by A. V. Pokrovsky) who were not suitable for reconstructive surgery or endovascular treatment. This study demonstrated the safety, feasibility, and short-term(3 months) efficacy of pCMV-vegf165 gene transfer,12,13which lead to conducting a phase 2b to 3 multicenter clinical trial. The study was conducted under the control of the Russian Ministry of Health and was completed in 2011. Patients enrolled in the study were subjected to a 6-month

We conducted a phase 2b/3 multicenter randomized controlled clinical trial of the intramuscular transfer of a plasmid DNA encoding vascular endothelial growth factor (VEGF) 165 with cytomegalovirus promotor (CMV) in patients with atherosclerotic lower limb ischemia. A total of 100 patients were enrolled in the study, that is, 75 patients were randomized into the test group and received 2 intramuscular injections of 1.2 mg of pCMV- vegf165, 14 days apart together with standard pharmacological treatment. In all, 25 patients were randomized into the control group and received standard treatment only. The following end points were evaluated within the first 6 months of the study and during a 1.5-year additional follow-up period: pain-free walking distance (PWD), ankle-brachial index (ABI), and blood flow velocity (BFV).

Inclusion Criteria:

• age more than 40 years;
• a history of stable claudication for at least 3 months;
• stage 2 to 3 chronic ischemia according to Fontaine classification (modified by A. V. Pokrovsky);
• presence of hemodynamically significant (stenosis >70% and/or occlusion) diffuse lesions of the interior and (or) posterior tibial arteries (distal lesion);
• voluntary informed consent signed and dated by the patient.

Exclusion Criteria:

• chronic lower limb ischemia of nonatherosclerotic genesis; stage 4 chronic ischemia according to Fontaine classification modified by A. V. Pokrovsky (ischemic ulcers and necrotic lesions);
• severe concomitant pathology with life expectancy <1 year;
• infectious diseases, history of cancer, or suspected malignancy;