Study to Assess the Efficacy and Safety of CLBS12 in Patients with Critical Limb Ischemia (CLI)

Main ASO Study: This study will compare safety and efficacy of intramuscular transplantation of autologous CD34+ cells (CLBS12) plus standard of care (SOC) pharmacotherapy (cell treatment arm) versus SOC pharmacotherapy alone (e.g., antiplatelets, anticoagulants, and vasodilators including prostanoids) (control arm) in subjects with CLI categorized as Rutherford score 4 or 5 due to ASO aged 20 to 85 years and with no endovascular or surgical revascularization options. Subjects assigned to the cell treatment arm will continue SOC pharmacotherapy and will also receive subcutaneous injections of GRAN® 5 ug/kg/day for 5 days and undergo apheresis on the last day of GRAN® administration. Then each subject in the cell treatment arm will receive intramuscular injections of autologous CD34+ cells. Subjects assigned to the control arm will continue to receive SOC pharmacotherapy alone with the possibility of receiving cell treatment via the rescue option.

BD Substudy: A single arm substudy is included to assess the safety and efficacy of intramuscular transplantation of CLBS12 in patients (N=\~5) with CLI categorized as 4 or 5 Rutherford score due to BD aged 20 to 85 years. Subjects who give informed consent will be screened for eligibility within 28 days before registration. Subjects will continue SOC pharmacotherapy and will also receive subcutaneous injections of GRAN® 5 µg/kg/day for 5 days (Pretreatment Days 1 5) to mobilize CD34+ cells into the peripheral blood and undergo apheresis on pretreatment Day 5 to collect CD34+ cells. The choice of pharmacotherapy will be made by the investigators.

Each subject in a cell treatment arm will receive intramuscular injections of up to 1 × 10\^6 autologous CD34+ cells/kg/limb. All subjects will be evaluated for efficacy and safety assessments during approximately 12 months.

Efficacy assessments include CLI free status, AFS, PFS, ABI, TBI, SPP, TcPO2, ICD, VAS, and AQA.