Effective treatment of chronic lower limb ischemia is one of the most challenging issues confronting vascular surgeons. There are a number of choices available to the vascular surgeon. Open or endovascular revascularization is the treatment of choice when applicable. Current pharmacological therapies play an auxiliary role and cannot prevent disease progression. Therefore, new methods of treatment are needed. 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). The pCMV-vegf165 therapy appeared to be significantly more effective than standard treatment. The PWD increased in the test group by 110.4%, 167.2%, and 190.8% at 6 months, 1 year, and 2 years after treatment, respectively. The pCMV-vegf165 intramuscular transfer caused a statistically significant increase in ABI and BFV. There were no positive results in the control group. Thus, pCMV-vegf165 intramuscular gene transfer is an effective method of treatment of moderate to severe claudication due to chronic lower limb ischemia.

The effective treatment of chronic lower limb ischemia is one of the most challenging issues confronting vascular surgeons. Current pharmacological therapies play an auxiliary role and cannot prevent disease progression, and new treatment methods are needed. pl-VEGF165, a gene therapy drug, was approved in Russia for the treatment of atherosclerotic peripheral arterial disease (PAD) after clinical studies in 2011. The study drug is an original gene construction in which pl-VEGF165 1.2 mg is the active substance.

Background: The effective treatment of chronic lower limb ischemia is one of the most challenging issues confronting vascular surgeons. Current pharmacological therapies play an auxiliary role and cannot prevent disease progression, and new treatment methods are needed. In 2011, a plasmid VEGF65-gene therapy drug was approved in Russia for the treatment of chronic lower limb ischemia ( ClinicalTrials.gov identifier: NCT03068585). The objective of this follow-up study was to evaluate the long-term safety and efficacy of gene therapy in patients with limb ischemia of atherosclerotic genesis. Aims: To evaluate the long-term safety and efficacy of the therapeutic angiogenesis, 36 patients in the treatment group (pl- VEGF165) and 12 patients in the control group participated in a 5-year follow-up study. Planned examinations were carried out annually for 5 years after pl- VEGF165 administration. Results: Differences in the frequency of major cardiovascular events (pl- VEGF165 5/36 versus control 2/12; p = 0.85), malignancies (pl- VEGF165 1/36 versus control 0/12; p = 0.38) and impaired vision (there was none in either group) over the 5-year follow-up period did not achieve statistical significance. The target limb salvage was 95% ( n = 36) and 67% ( n = 12) in the pl- VEGF165 and control groups, respectively. The pain-free walking distance value increased by 288% from 105.7 ± 16.5 m to 384 ± 39 m in the treatment group by the end of the fifth year, with a peak of 410.6 ± 86.1 m achieved by the end of the third year. The ankle-brachial index (ABI) increased from 0.47 ± 0.01 to 0.56 ± 0.02 by the end of the first year, with a subsequent slight decrease to 0.51 ± 0.02 by the fifth year. The maximum increment of transcutaneous oximetry test (tcoO₂) by 36%, from 66.6 ± 3.7 mm Hg to 90.7 ± 4.9 mm Hg, was observed by the end of the second year. Conclusion: The therapeutic effect of angiogenesis induction by gene therapy persists for 5 years.

Bone grafts are medical devices that are in high demand in clinical practice for substitution of bone defects and recovery of atrophic bone regions. Based on the analysis of the modern groups of bone grafts, the particularities of their composition, the mechanisms of their biological effects, and their therapeutic indications, applicable classification was proposed that separates the bone substitutes into “ordinary” and “activated.” The main differential criterion is the presence of biologically active components in the material that are standardized by qualitative and quantitative parameters: growth factors, cells, or gene constructions encoding growth factors. The pronounced osteoinductive and (or) osteogenic properties of activated osteoplastic materials allow drawing upon their efficacy in the substitution of large bone defects.

Bone grafting and reconstruction are still challenging in clinical practice because of the limitations of bone autografts and the drawbacks of currently approved bone substitutes. We thus developed a gene-activated bone substitute based on octacalcium phosphate and naked plasmid DNA carrying the vascular endothelial growth factor gene. This advanced combined therapy medicinal product had no cytotoxic effects in vitro, slightly decreased bone marrow mesenchymal stromal cell (MSC) doubling time, and was characterized by a prolonged level of gene construct delivery in vivo in a luciferase bioimaging assay. In the model of critically sized cranial bone defects in rabbits, the gene-activated matrix increased bone tissue formation through angiogenesis induction. After preclinical studies, we conducted an open-label non-randomized clinical trial (NCT03076138). The primary study outcome was the proportion of patients with newly formed bone tissue within the surgical area as measured by computed tomography within 6 months after surgery. The main secondary outcomes included frequencies of adverse events (AEs) and serious adverse events (SAEs) as well as the surgical failure rate. After completing the clinical trial, the patients had dental implants placed in the bone grafting area, and trephine biopsy samples were collected. In total, 20 patients with alveolar ridge atrophy (n = 16) and jaw bone defects (n = 4) were enrolled in the study. There were no AEs or SAEs during the clinical trial or the follow-up period (30 months). In all patients, newly formed tissues with a bone density of 908.13 ± 114.40 HU were detected within the zone of bone grafting. There were no significant differences between the subgroups of patients with atrophy and bone defects: 915.28 ± 125.85 and 879.56 ± 48.36 HU, respectively (p = 0.60). Histological analysis showed that the bone grafting area comprised newly formed bone tissue with some fragments of the gene-activated bone substitute partially resorbed and integrated with bone, without fibrous tissue in between. The preclinical data and clinical trial results proved the feasibility, safety, and efficacy of the investigated material for jaw bone grafting, allowing us to bring the world's first gene-activated bone substitute from bench to bedside.