YQ23 Study in Patients With Critical Limb Ischaemia

Inclusion Criteria: * Diagnosis of CLI (Rutherford Classification stage 4, 5 or 6) including at least one of the following: 1. resting ankle systolic pressure (either dorsalis pedis or posterior tibial artery) \<=70 mmHg in affected limb 2. resting toe systolic pressure \<=50 mmHg in affected limb 3. TcPO2 \<=30 mmHg * One of the following clinical presentations: 1. pain at rest 2. ischaemic ulcer, and/or focal gangrene for at least 2 weeks * Diagnosis of severe lower extremity peripheral artery occlusive disease as evidenced by either: 1. Documented significant stenosis (\>=75%) of \>=1 of the following arteries: superficial femoral, popliteal, and infra-popliteal arteries, as assessed by imaging test, or 2. ABI \<=0.80 or TBI \<=0.60 of the index leg (in the event of non-compressible ankle arteries) for patients without a prior history of limb revascularization on the index leg, or an ABI \<=0.85 or TBI \<=0.65 of the index leg (in the event of non-compressible ankle arteries) for patients with a prior history of limb revascularization on the index leg. * Contraceptive use 1. Male patients and their female spouses/partners who are of childbearing potential must agree to use a high effective contraception consisting of two forms of birth control detailed in the protocol during the treatment period and for at least 6 days after the dose of the study treatment and refrain from donating sperm during this period 2. A female patient is eligible if she is not pregnant, not breastfeeding, and at least on of the following conditions applies: (i) not a woman of childbearing potential (WOCBP), (ii) A WOCBP who agrees to follow the contraceptive guidance in the protocol during the treatment period and for at least 6 days after the dose of study treatment and refrain from donating ova during this period * Patient is capable of giving signed informed consent which includes compliance with the requirements and restrictions listed in the informed consent and the protocol Exclusion Criteria: * Patients who have undergone successful revascularisation on the index leg within 4 weeks of the qualifying event * Patients with estimated life expectancy \<12 months * Acute limb ischaemia due to thromboembolism within 2 weeks of the qualifying event * Recent myocardial infarction within 30 calendar days prior to signing informed consent * Recent stroke within 30 calendar days prior to signing informed consent * Known history of severe congestive heart failure as determined through review of medical history * Haemoglobin \<8 g/dL, albumin \<3 g/dL or other clinically significant abnormalities in the laboratory tests at screening * Unwilling to complete follow-up evaluation * Uncontrolled arterial hypertension with systolic blood pressure (SBP) \>180 mmHg and/or diastolic blood pressure (DBP) \>100 mmHg at screening * Patients with history of long QT syndrome or whose QTc (calculated according to Bazett formula QTc = QT/ √RR) \>470 ms at screening * Patients with severe left ventricular dysfunction of \<40% at screening * Patients with clinically significant abnormalities in ECG parameters (other than QTc) or in the physical examination at screening that might comprise patient safety * History of coagulopathy * Patients having significant renal impairment with estimated glomerular filtration rate (eGFR) \<30 mL/min/1.73 m2 as determined by the 4-variable Modification of Diet in Renal Disease (MDRD) equation at Screening, except those patients who are on continuous ambulatory peritoneal dialysis(CAPD) or hemodialysis (HD) * Significant liver impairment (abnormal Liver Function Tests \>3 x upper limit of normal) * Patients with active Hepatitis B infection (HBsAg positive and HBeAg positive) at screening * Patient with a positive test for Hepatitis C virus antibody (anti-HCV) at screening * Patient with known history of infection with human immunodeficiency virus (HIV) or any other active or chronic infection * Patients with evidence of uncontrolled hypo- or hyperthyroidism * History active malignancy (as determined through review of medical history), excluding local skin cancer (basal or squamous cell carcinoma) * Patients unable to provide informed consent * Known allergy to bovine products * Receipt of bovine haemoglobin-based oxygen carrier (HBOC) or other HBOC in the past * Use of an investigational drug or treatment within 12 months prior to signing informed consent; concurrent participation in any other investigational protocol * Pregnancy and breastfeeding, as well as unwillingness to use effective methods contraception for women of childbearing potential