This is a multicenter, randomized, double-blind, placebo-controlled Phase III clinical study designed to evaluate the efficacy of recombinant human tissue-type plasminogen activator variant (rhTNK-tPA) (0.25 mg/kg, maximum dose 25 mg) compared with placebo in patients with acute large vessel occlusive stroke who present within 4.5 to 24 hours of symptom onset. The study plans to enroll patients with acute large vessel occlusive stroke who present within 4.5 to 24 hours of symptom onset (including wake-up strokes and strokes without witnesses). A centralized 1:1 randomization will be adopted, and eligible participants will be randomly assigned to two groups: the experimental group will receive rhTNK-tPA at a dose of 0.25 mg/kg, while the placebo group will receive rhTNK-tPA placebo.

This multicenter, randomized, double-blind, placebo-controlled Phase III clinical study aims to evaluate the efficacy of recombinant human tissue-type plasminogen activator variant (rhTNK-tPA) (0.25 mg/kg, maximum dose 25 mg) compared with placebo in patients with acute large vessel occlusive stroke who present within 4.5 to 24 hours of symptom onset. The study initially planned to enroll 890 patients, who would be randomly assigned to the experimental group (rhTNK-tPA group) or the control group (placebo group) at a 1:1 ratio. After an unblinded sample size re-estimation during the interim analysis, the maximum sample size could be adjusted to 1,300 patients.

Key characteristics of the primary study population include: age ≥ 18 years; time from symptom onset to treatment ranging from 4.5 hours to 24 hours; occlusion of the internal carotid artery, M1 or M2 segment of the middle cerebral artery confirmed by computed tomography angiography (CTA)/magnetic resonance angiography (MRA), which is the responsible vessel for the signs and symptoms of acute ischemic stroke; modified Rankin Scale (mRS) score ≤ 1 before symptom onset; baseline National Institutes of Health Stroke Scale (NIHSS) score ≥ 6; and presence of target mismatch on computed tomography perfusion (CTP) or magnetic resonance imaging (MRI) combined with magnetic resonance perfusion (MRP) (ischemic core volume < 70 mL, mismatch ratio ≥ 1.8, and mismatch volume ≥ 15 mL). Patients with a known allergy to rhTNK-tPA and those with contraindications to thrombolysis were excluded.

The entire study duration is approximately 90 days, including the screening period, treatment period, and follow-up period. The primary study endpoint is the proportion of participants with a modified Rankin Scale (mRS) score of 0-1 at the 90-day follow-up.

Inclusion Criteria:

1. Aged ≥ 18 years, regardless of gender;
2. Time from symptom onset to treatment is 4.5 - 24 hours(Including the boundary values.), including patients with wake-up stroke or stroke without witnesses; the time of symptom onset is defined as the "last known normal time";
3. Modified Rankin Scale (mRS) score ≤ 1 before stroke onset;
4. Baseline National Institutes of Health Stroke Scale (NIHSS) score ≥ 6;
5. Neuroimaging findings: occlusion of the internal carotid artery (ICA), M1 or M2 segment of the middle cerebral artery (MCA) confirmed by computed tomography angiography (CTA)/magnetic resonance angiography (MRA), which is the responsible vessel for the signs and symptoms of acute ischemic stroke; presence of target mismatch on computed tomography perfusion (CTP) or magnetic resonance imaging (MRI) + magnetic resonance perfusion (MRP) (ischemic core volume < 70 mL, mismatch ratio ≥ 1.8, mismatch volume ≥ 15 mL);
6. Voluntary signing of the informed consent form by the participant or their legal guardian.

Exclusion Criteria:

1. Patients with known allergy to recombinant human tissue plasminogen activator (rhTNK-tPA);
2. Patients with an expected life expectancy of less than 1 year;
3. Patients with rapidly improving symptoms (which may indicate spontaneous recanalization), as determined by the investigator;
4. Patients with a score of > 2 on Item 1a (Level of Consciousness) of the National Institutes of Health Stroke Scale (NIHSS), or those who had a seizure at stroke onset, or had hemiplegia after seizure, or had other neurological/psychiatric disorders that rendered them unable or unwilling to cooperate;
5. Severe and persistent hypertension uncontrolled by medication ;
6. Blood glucose < 2.8 mmol/L or > 22.2 mmol/L;
7. Active internal bleeding with a high risk of hemorrhage;
8. Any known coagulation disorder;
9. Known platelet function defect or platelet count less than 100×10⁹/L;