Critical limb ischemia is characterized by impairment of blood flow to the legs and feet caused by blockage of the arteries.

In a 21-patient Phase 1/2 clinical trial, ALD-301 was well-tolerated, and we believe the trial data provided initial evidence of improved blood flow and improved clinical status within the ALD-301 treatment group. For example, at 12 weeks after treatment, four of the 11 patients treated in the ALD-301 treatment group experienced an improvement in the Rutherford category, which is a well-accepted clinical categorization for the extent of critical limb ischemia, to the degree that they were no longer classified as having critical limb ischemia. Critical limb ischemia patients with no revascularization options, such as those who participated in this trial, rarely experience improvements in Rutherford category. In addition, at 24 weeks after treatment, ten of the 11 patients in the ALD-301 treatment group were alive and had not required amputation of their affected limbs. Typically, up to 35% of critical limb ischemia patients with no revascularization options require an amputation within six months.