Efficacy and Safety of Intra-Arterial Albumin as Adjunct to Mechanical Thrombectomy in Acute Ischemic Stroke: A Multicenter, Prospective, Open-Label, Endpoint-Blinded, Randomized Controlled Clinical Trial (AMASS2)

Stroke remains a predominant global public health challenge, ranking as the third leading cause of death and the fourth leading contributor to disability-adjusted life years (DALYs). According to the Global Burden of Disease Study 2021, there are approximately 93.8 million prevalent stroke cases and 11.9 million new cases worldwide. China bears one of the heaviest burdens, with over 2 million new cases annually. Acute ischemic stroke (AIS), caused by acute cerebrovascular occlusion, accounts for 80% of all strokes. Approximately 30% of AIS cases result from large vessel occlusion (LVO), which typically carries a poor prognosis due to the extensive area of infarction . Research indicates that early recanalization significantly improves clinical outcomes. Currently, intravenous thrombolysis (IVT) and mechanical thrombectomy (MT) are the standard treatments for achieving recanalization . For LVO-related AIS, MT has become the preferred clinical approach due to its extended therapeutic window and superior recanalization rates . However, despite successful recanalization in over 70% of patients, nearly 50% fail to achieve functional independence at 90 days, and mortality remains above 15% . Therefore, enhancing long-term functional outcomes in post-MT patients is a critical unmet clinical need. Human albumin is the most abundant protein in plasma. Beyond maintaining colloid osmotic pressure, it also possesses multiple biological effects, including anti-inflammatory, anti-platelet aggregation, antioxidant, and endothelial protective properties. We conducted a Phase I clinical trial (AMASS-1) for patients post-mechanical thrombectomy, administering human albumin via the internal carotid artery. The results showed that intra-arterial infusion of 20% human albumin at a dose of 0.60 g/kg was safe, with no significant differences in serious adverse reactions such as mortality [Albumin group (6.7%) vs Control group (6.7%), P > 0.05] and symptomatic intracranial hemorrhage [Albumin group (6.7%) vs Control group (13.3%), P > 0.05] compared to the control group. In summary, albumin adjunctive therapy demonstrates good safety and potential neuroprotective effects in patients after mechanical thrombectomy. To further systematically evaluate its efficacy and safety, we plan to conduct a Phase II clinical trial of mechanical thrombectomy combined with intra-arterial albumin infusion for acute ischemic stroke. This is a multicenter, prospective, open-label, endpoint-blinded, randomized controlled trial designed to evaluate the efficacy and safety of intra-arterial infusion of 20% human serum albumin combined with mechanical thrombectomy versus mechanical thrombectomy alone in patients with acute ischemic stroke due to anterior circulation large vessel occlusion who have achieved recanalization after mechanical thrombectomy. A total of 306 patients are planned to be enrolled and randomly assigned in a 1:1 ratio using a dynamic minimization method to two groups: the Albumin Group (0.6 g/kg 20% human serum albumin plus Mechanical Thrombectomy) and the Control Group (Mechanical Thrombectomy alone). The primary efficacy objective of this study is to evaluate whether immediate intra-arterial infusion of 20% human albumin (0.6 g/kg) via the internal carotid artery following successful recanalization (eTICI ≥2b) improves clinical outcomes in patients with acute anterior circulation large vessel occlusion stroke, compared with mechanical thrombectomy alone. The study also aims to evaluate the safety and feasibility of immediate intra-arterial infusion of 20% human albumin (0.6 g/kg) via the internal carotid artery in patients with acute anterior circulation large vessel occlusion stroke who have achieved successful recanalization (eTICI ≥2b) following standard mechanical thrombectomy.