Pharmacological characterization and neuroprotective efficacy of ZHB103, a novel long-acting rhKLK1

Exogenous plasma kallikrein 1 (KLK1) supplementation is hypothesized to have both immediate and long-lasting actions that may improve outcomes following acute ischemic stroke. ZHB103, a polyethylene glycol (PEG)-modified long-acting recombinant human KLK1 (LA-rhKLK1), has been developed as a candidate for exogenous KLK1 supplementation in stroke patients and for the prevention of stroke. In pharmacokinetic and toxicokinetic studies, ZHB103 exhibited high bioavailability, a prolonged half-life (T_1/2) and no treatment-related adverse effects after intramuscular injection in Sprague-Dawley rats and cynomolgus monkeys. Single-dose or once-weekly administration of ZHB103 demonstrated both short-term and long-term protective effects against ischemic stroke in oxygen-glucose deprivation/reoxygenation models, H₂O₂-induced oxidative stress models and experimental stroke models. Compared with rKLK1 (the proprotein of ZHB103, a short-acting non-PEGylated recombinant KLK1), Sanbexin (Edaravone and Dexborneol concentrated solution for injection) or HUK (human urinary kallidinogenase, a form of tissue kallikrein 1 from urine), ZHB103 promoted cell proliferation, inhibited apoptosis, reduced inflammatory factor levels in the acute stage of stroke models and improved cognitive function recovery during the later recovery stage via a significantly prolonged duration of B2 receptor (B2R)-mediated signaling pathway (eNOS-Akt-ERK1/2-CREB-Bcl-2) activation. The introduction of B2R inhibitor HOE-140 further confirmed, both in vitro and in vivo that ZHB103 exerts its efficacy in stroke treatment through upregulation of B2R and activation of its downstream eNOS signaling pathway. These results suggest that the administration frequency of ZHB103 may be reduced to once weekly, demonstrating the advantages of PEG-conjugation strategy in improving patient compliance among stroke patients in clinical practice.