Impact of poly-arginine peptides R18D and R18 on alteplase and tenecteplase thrombolysis in vitro, and neuroprotective stability to proteolysis.

The poly-arginine peptides R18D and R18 represent novel potential neuroprotective treatments for acute ischaemic stroke. Here we examined whether R18D and R18 had any significant effects on the thrombolytic activity of alteplase (tPA) and tenecteplase (TNK) on clots formed from whole blood in an in vitro thrombolysis plate assay. R18D and R18 were examined at concentrations of 0.25, 0.5, 1, 2, 4, 8 and 16 µM during the 1-h thrombolytic assay. We also included the well-characterised neuroprotective NA-1 peptide as a control. R18D, R18 and NA-1 all reduced tPA or TNK percentage clot lysis by 0-9.35%, 0-3.44% and 0-4.8%, respectively. R18D, R18 and NA-1 had a modest and variable effect on the lag time, increasing the time to the commencement of thrombolysis by 0-9.9 min, 0-5.53 min and 0-7.16 min, respectively. Lastly, R18 and NA-1 appeared to increase the maximal activity of the thrombolysis reaction. In addition, the in vitro anti-excitotoxic neuroprotective efficacy of R18D and R18 was not affected by pre-incubation for 1-2 h or overnight with tPA or TNK, whereas only R18D retained high anti-excitotoxic neuroprotective efficacy when pre-incubated in a synthetic trypsin (TrypLE Express). The present in vitro findings suggest that neither R18D or R18 when co-administered with the thrombolytic inducing agents tPA or TNK are likely to have a significant impact when used clinically during clot thrombolysis and confirm the superior proteolytic stability of the R18D peptide.

Tenecteplase for Acute Ischemic Stroke: Current Evidence and Practical Considerations.

Tenecteplase offers pharmacological advantages over alteplase, and growing evidence supports its consideration for the treatment of patients with acute ischemic stroke. Its ease of administration as a single bolus makes it a preferable agent for patients who need to be urgently transported to a comprehensive stroke center for endovascular therapy (drip and ship) and for patients first evaluated at comprehensive stroke centers who are eligible for endovascular intervention (combined intravenous and endovascular approach). Recent randomized controlled trials indicated that the efficacy of tenecteplase may be similar to that of alteplase in patients with mild strokes and that it is superior to alteplase for patients with more severe strokes from a large vessel occlusion. Cumulative evidence currently favors the use of the 0.25 mg/kg dose. While tenecteplase has not been approved by regulatory agencies in the USA or the EU for the treatment of acute ischemic stroke, ongoing trials and additional clinical experience from countries where it is already being used in practice will likely clarify the role of tenecteplase for the acute management of ischemic stroke in the near future.

Comparative analysis of fibrinolytic properties of Alteplase, Tenecteplase and Urokinase in an in vitro clot model of intracerebral haemorrhage.

OBJECTIVE: Hematoma lysis with recombinant tissue plasminogen activator (rtPA) has emerged as an alternative therapy for spontaneous intracerebral and intraventricular haemorrhage (ICH and IVH). However, the MISTIE III and CLEAR III trial failed to show significant improvement of favourable outcomes. Besides experimental and clinical trials revealed neurotoxic effects of rtPA. The demand for optimization of fibrinolytic therapy persists. Herein, we used our recently devised clot model of ICH to systematically analyse fibrinolytic properties of rtPA, tenecteplase and urokinase. METHODS: In vitro clots of human blood (size: 25 ml and 50 ml; age: 1.5 tenecteplase, 24 tenecteplase and 48 tenecteplase) were produced and equipped with a catheter into the clot core for drug delivery and drainage. Various doses of tenecteplase and urokinase with different treatment periods were examined (overall 117 clots), assessing the optimal dose and treatment time of these fibrinolytics. Clots were weighed before and at the end of treatment. These results were compared with clots treated with 1 mg rtPA or with 0.9% sodium chloride solution. RESULTS: The optimal treatment scheme of tenecteplase was found to be 100 IU with an incubation time of 30 min, for urokinase it was 50 000 IU with an incubation time of 20 min. The relative clot end weight of tenecteplase and urokinase (31.3±11.9%, 34.8 ±7.7%) was comparable to rtPA (36.7±10.7%). Larger clots were more effectively treated with tenecteplase compared to the control group (P=0.0013). urokinase and tenecteplase had similar lysis rates in aged clots and 90 min clots. One and two repetitive treatments with tenecteplase were as effective as two and three cycles of urokinase. CONCLUSIONS: In our in vitro clot model we could determine optimal treatment regimens of tenecteplase (100 IU, 30 min) and urokinase (50 000 IU, 20 min). Urokinase and tenecteplase were comparable in their fibrinolytic potential compared to 1mg rtPA in small clots and showed an effective lysis in aged clots. tenecteplase was more effective in larger clots.

3K3A-Activated Protein C Variant Does Not Interfere With the Plasma Clot Lysis Activity of Tenecteplase.

BACKGROUND AND PURPOSE: A recombinant engineered variant of APC (activated protein C), 3K3A-APC, lacks anticoagulant properties (<10%) while preserving APCs anti-inflammatory, anti-apoptotic, and neuroprotective functions and is very promising in clinical trials for ischemic stroke. Therapeutic intervention with single bolus administration of the third-generation tPA (tissue-type plasminogen activator), tenecteplase, is anticipated to be widely adopted for treatment of acute ischemic stroke. 3K3A-APC is well-tolerated in stroke patients dosed with alteplase, and in vitro studies show 3K3A-APC does not interfere with alteplase-induced clot lysis. The purpose of this in vitro study was to assess the influence of 3K3A-APC on tenecteplase-induced clot lysis. METHODS: Tenecteplase-mediated lysis of thrombin generated plasma clots of human normal pooled plasma was monitored in the presence of varying doses of 3K3A-APC. The effects on fibrinolysis by tenecteplase and alteplase were compared. RESULTS: The presence of 3K3A-APC shortened the time for clot lysis induced by tenecteplase at very low levels but not at higher therapeutic concentrations of tenecteplase. Comparisons of alteplase-mediated clot lysis to tenecteplase clot lysis showed that both thrombolytic agents behaved similarly in the presence of 3K3A-APC. CONCLUSIONS: These results indicate that 3K3A-APC does not interfere with tenecteplase's clot lysis function.

Tenecteplase versus alteplase in acute ischemic stroke: systematic review and meta-analysis.

Tenecteplase is a product of genetic modification of recombinant tissue plasminogen activator with superior pharmacodynamic and pharmacokinetic properties. This meta-analysis was to determine whether intravenous thrombolysis with tenecteplase in patients with acute ischemic stroke has better efficacy and safety outcomes than with intravenous alteplase. PubMed, Cochrane Central Register of Controlled Trials, WHO International clinical trials registry platform (ICTRP), Australian New Zealand Clinical Trials Registry (ANZCTR), EU Clinical Trials Register (EU-CTR) and ClinicalTrials.gov were searched for trials comparing tenecteplase with alteplase in acute ischemic stroke. Functional outcomes (modified Rankin Scale at 90 days), early major neurological improvement, rates of any intracerebral haemorrhage, symptomatic intracerebral haemorrhage and mortality rate at 90 days were the outcomes compared. Four randomized controlled trials involving 1334 patients were included. The Tenecteplase group compared to the alteplase group had significantly better early major neurological improvement (RR = 1.56, 95% CI [1.00, 2.43], p = 0.05). There was no significant difference between tenecteplase and alteplase in excellent functional outcome at 90 days, good functional outcome at 90 days, any intracerebral haemorrhage, symptomatic intracerebral haemorrhage or mortality at 90 days. Our meta-analysis found tenecteplase to be significantly favouring one outcome: early major neurological improvement. Other outcomes did not differ between the tenecteplase and alteplase groups. Trials of cost-effective/benefit analysis comparing tenecteplase versus alteplase and tenecteplase versus endovascular treatment are necessary to reinforce the evidence for the potential cost advantage of tenecteplase.