Design of a potentially registrational study of sakigake-designated GCSF-Mobilized autologous CD34 cell (CLBS12) Therapy of no-option critical limb ischemia including arteriosclerosis obliterans and Buerger's Disease

Abstract

Background & Aim CLBS12 (autologous, mobilized peripheral blood derived selected CD34 cells) has previously been studied for the treatment of No-Option Critical Limb Ischemia (NOCLI) in Phase 1 and 2 studies in Japan and the United States. These studies demonstrated statistically significant improvement in key outcome measures including reduced Rutherford category, improved walking distance, reduction in pain, improvement in blood flow and tissue oxygenation, reduction in size and number of ulcers, and improved amputation-free survival. In one of the Japan studies, more than 80% of subjects treated with a single administration of CD34 cells became CLI-free and maintained this status through 4 years of observation. The promising results of these studies led to discussions with the PMDA regarding the design of a confirmatory study that, with a favorable outcome, could support registration of CLBS12 in Japan for NOCLI under the new regenerative medicine regulations. Methods, Results & Conclusion The study is a prospective, randomized clinical trial in subjects with arteriosclerosis obliterans (ASO; n=30) or Buerger's Disease (BD; n=5). All patients receive standard-of-care treatment (SOC). The study calls for randomization of 30 subjects with ASO to receive either CLBS12 or to continue with SOC alone. Additionally, 5 subjects with BD were to be allocated to a sub-study and receive CLBS12 while continuing SOC treatment. The primary endpoint for the study is ability to achieve a continuous CLI-free state. Other key measures include progression-free, amputation-free, and overall survival; Rutherford category; tissue oxygenation; blood flow; ulcer size, depth, and infection; pain; and quality-of-life. For preparation of CLBS12, subjects are mobilized with GCSF 5 µg/day for 5 days, then undergo apheresis to collect a mononuclear cell fraction. CD34 cells are separated using a magnetic separation method. CLBS12 is formulated as a cell suspension in proprietary media in a 10 mL volume for administration as a series of 20 intramuscular injections in one affected limb. The study was initiated in December 2017 and is expected to be completed in 2020. The BD sub-study has enrolled 6 subjects and half have achieved a continuous CLI-free state. Interim data from the trial will be presented.