Update on clinical trials evaluating the effect of biologic therapy in patients with critical limb ischemia.

Critical limb ischemia (CLI) represents the most severe degree of peripheral arterial disease and is associated with significant morbidity and mortality. In patients with CLI who do not have revascularization options, major amputation is required within 1 year in as many as 40% of patients. Biologic therapies, which include gene therapy and cellular therapy, offer the potential to promote wound healing and prevent amputation in patients who otherwise have poor options for revascularization. Several recent phase 2 trials have shown acceptable safety and suggest that these biological therapies have the potential to improve outcomes in patients with "no-option" CLI. Phase 3 trials are now in progress. This report summarizes the recent results of, and future plans for, gene and cellular therapy clinical trials in patients with CLI.