O2L-001, an innovative thrombolytic to evacuate intracerebral haematoma.

Abstract

Intracerebral haemorrhage is an unmet medical need affecting more than 3 million people every year worldwide and leading to the formation of an intracerebral haematoma. 2022 updated guidelines for the management of intracerebral haemorrhage patients recognize that minimally invasive approaches for evacuation of supratentorial intracerebral haemorrhage have demonstrated reductions in mortality compared with medical management alone. However improvement of functional outcome with a procedure involving thrombolytic therapy was neutral in the last large Phase 3 clinical trial and requires a more effective and safer thrombolytic agent than those available on the market. Here, we demonstrated that O2L-001 allowing the extended-release of W253R/R275S rtPA, a new rtPA variant named OptPA, offers an improved efficacy for haematoma evacuation as well as the best safety. OptPA was produced in chinese hamster ovary cell line before purification, nanoprecipitation using the NANOp2Lysis® technological platform followed by suspension in a solution of 17% poloxamer 407 to obtain O2L-001. Plasmin generation assays were performed to demonstrate O2L-001 safety. Ex vivo haematoma models using human blood were used to show O2L-001 thrombolysis properties and efficacy. For the best translational significance, a clinical size haematoma was used in order to ensure catheter placement and to allow thrombolytic agent deliverance into the core of the haematoma through a minimally invasive procedure. The capacity of OptPA to convert plasminogen into plasmin is strongly decreased compared to rtPA, reducing potential bleeding events. However, a clot lysis assay shows that OptPA had the same fibrinolytic activity than rtPA. Interestingly, we demonstrated that long term exposure to thrombolytic agent were essential to achieve high thrombolysis efficacy. Indeed, 24 hours continuous exposure to 0.1 µg/mL rtPA had similar efficacy than repeated short exposure to 30 µg/mL rtPA. This finding led to the development of O2L-001 allowing the extended release of OptPA in the first 6 h after injection. An ex vivo model using human blood was used to demonstrate O2L-001 efficacy. Interestingly, unlike rtPA, O2L-001 is able to induce the complete lyse of 5 ml haematoma. On clinical size haematomas (obtain from 30 ml of human blood), a single injection of O2L-001 at 1 mg/ml into the core of the haematoma led to an increase of thrombolysis of 44% when compared to rtPA. Altogether these results demonstrate that O2L-001 is a new hope for haematoma evacuation and the treatment of intracerebral haemorrhage patients.