Interleukin-6 Receptor Inhibition for Symptomatic Intracranial Atherosclerosis

Inclusion Criteria:

• Male or non-pregnant women with acute stroke symptoms aged over 18 years.

• Patients having an ischemic stroke or a TIA prior to randomization (Patients havingan acute ischemic stroke within 72 hours with NIHSS score≤5 at baseline, or patientshaving a TIA within 72 hours with Oxfordshire Community Stroke Project on the basisof age, blood pressure, clinical features, and duration of TIA symptoms (ABCD2)score≥4 at baseline).

• The entry event is attributed to symptomatic atherosclerosis (50-99%) in anintracranial qualifying artery (intracranial carotid artery (C4-7), middle cerebralartery (M1), intracranial vertebral artery or basilar artery) confirmed by CT, MRangiography, or digital subtraction angiography.

• Informed consent obtained from patients or their legal representatives.

• Willing to be followed up as required by the clinical study protocol.

Exclusion Criteria:

• Thrombolytic therapy or thrombectomy within 24 hours prior to enrollment.

• Pre-stroke mRS score ≥ 2.

• Combined or previous intracranial hemorrhage: hemorrhagic stroke, epidural hematoma,subdural hematoma, intraventricular hemorrhage, subarachnoid hemorrhage, etc.

• Any of the following unequivocal cardiac source of embolism: chronic or paroxysmalatrial fibrillation, sinus node dysfunction, mitral stenosis, prosthetic heartvalves, endocarditis, left ventricular mural thrombus or valvular vegetation,myocardial infarction within three months, dilated cardiomyopathy, spontaneousechogenic defects in the left atrium or an ejection fraction of less than 30%.

• Intracranial arterial stenosis due to arterial dissection, Moya Moya disease; herpeszoster, varicella zoster or other viral vasculopathy; neurosyphilis; radiationinduced vasculopathy; fibromuscular dysplasia; sickle cell disease;neurofibromatosis; post-partum angiopathy; suspected vasospastic process, suspectedrecanalized embolus; any known vasculitic disease.

• Extracranial stenosis ≥50%, subclavian arterial stenosis≥50% or subclavian stealsyndrome.

• Previous interventions for intracranial arterial stenosis.

• Concurrent intracranial tumors, intracranial aneurysms or arteriovenousmalformations

• Neutrophil < 2×10 9/L.

• Platelet < 100×10 9/L.

• Serum alanine aminotransferase (ALT) or aspartate aminotransferase (AST) levelsgreater than 1.5 times the upper limit of normal.

• Active infections including localized.

• Evidence of HIV or hepatitis B positivity.

• Positive tuberculosis-related tests.

• Concurrent peptic ulcer, diverticulitis or inflammatory bowel disease.

• Concurrent malignant tumors, recent bone marrow transplant or recent organtransplant.

• Systolic blood pressure ≥ 180 mmHg or diastolic blood pressure ≥ 110 mmHg despiteblood pressure control.

• Known allergy to tocilizumab or excipients.

• Use of immunosuppressive drugs or systemic use of antibiotics.

• Received any live or live attenuated vaccine within 4 weeks prior to enrollment orplan to receive a live or live attenuated vaccine during the study.

• History of demyelination or presence of neurological symptoms suggestive ofdemyelination.

• Previously existing neurological or psychiatric disorders that could potentiallyconfuse neurological function assessment.

• An expected survival less than 90 days.

• Participation in another interventional clinical study.

• Patients unsuitable for enrollment in the clinical trial according to investigatorsdecision making.