No Clinical Benefit of Intramuscular Delivery of Bone Marrow-derived Mononuclear Cells in Nonreconstructable Peripheral Arterial Disease

Abstract

Prospects for no-option, end-stage peripheral artery disease (PAD) patients remain poor. Although results from open and semiblinded studies fuel hope for cell-based strategies in no-option patients, so far conclusions from the available placebo-controlled studies are not supportive. With the intention to end the remaining controversy with regard to cell therapy for PAD we conducted a confirmatory, double-blinded randomized placebo-controlled phase 3 trial. This randomized controlled trial was registered (NCT00539266). Inclusion criteria included stable or progressive disabling PAD, no imminent need for amputation, absent accepted options for revascularization. Diabetic disease was an exclusion criterion. Bone marrow (500-700 mL) was harvested and bone marrow-derived mononuclear cells were concentrated to 40 mL. Concentrated cells or placebo (diluted blood) were intramuscularly injected at 40 locations of the calf muscle. Fifty-four patients (mean (sd) age 58.2 (14.2) yrs, 58% males) were randomized. Twenty-eight patients received BM-MNCs, 26 placebo. Baseline criteria were similar in the 2 groups. No significant differences were observed for the primary (number of amputations, (pain free) walking distance) and secondary outcome parameters (ankle brachial index, pain scores, quality of life (SF-36)). This fully blinded replication trial of autologous BM-MNC fails to confirm a benefit for cell therapy in no-option PAD patients, consequently BM-MNC therapy should not be offered as a clinical treatment. Apparent contrasting conclusions from open and controlled studies underscore the importance of a controlled trial design in evaluating cell-based interventions in PAD.