This trial aims to investigate the use of a proprietary mesenchymal stem cell product in the treatment of advanced peripheral arterial disease. The trial is being conducted in 15 centres in 12 US states and four centres in Germany by a biotech company Pluristem Ltd. Pluristem has developed a proprietary product called PLX PAD composed of mesenchymal stem cells obtained from human placenta. The trial expects to enrol 150 patients suffering from peripheral artery disease with intermittent claudication by December 2015. Participants will be randomly divided to one of four groups. The first group will receive two low-dose injections of the cells. The second will receive two high-dose injections of the cells. The third group will receive one injection of high-dose cells and one placebo injection. The final group will receive two placebo. Participants will be monitored for complications and improvements in their condition. Pluristem Ltd is conducting a similar global trial for Critical Limb Ischaemia resulting from advanced peripheral arterial disease.