Evaluation of the Efficacy and Safety of Injectable RGL-2102 in Patients with Severe Lower Limb Ischemia: a Randomized, Double-Blind, Parallel-Group Phase ? Clinical Trial

INTERVENTION: Arm 1:RGL‐2102 for Injection, Multiple Doses;Arm 2:RGL‐2102 for Injection, multiple doses; followed by normal saline, multiple doses; CONDITION: Lower limb ischemic disease PRIMARY OUTCOME: Change in pain score from baseline to Day 180;Change in ulcer area from baseline to Day 180; SECONDARY OUTCOME: Safety; INCLUSION CRITERIA: 1. Male or female subjects aged >=20 and <=80 years on the day of signing the informed consent form; 2. Patients diagnosed with arteriosclerosis obliterans (ASO) or thromboangiitis obliterans (TAO) based on digital subtraction angiography (DSA) or computed tomographic arteriography (CTA), combined with medical history and clinical manifestations, with Rutherford classification Grade 4 (with rest pain) or Grade 5 (with ulceration), and meeting all of the following criteria (if both lower limbs have ischemia, the investigator shall select one limb as the study limb after evaluation): 1) Ankle systolic pressure <=70 mmHg, or ABI <=0.5, or TcPO2 <30 mmHg; 2) Ischemic rest pain or ulceration lasting for more than 2 weeks; 3) Severe stenosis (>=70%) or occlusion of infrapopliteal arteries, with or without superficial femoral or popliteal artery involvement, confirmed by DSA or CTA within 3 months prior to randomization; 3. NRS score of rest pain in the stud