Background: Hemodialysis (HD) grafts often fail due to stenosis at the venous anastomosis and thrombotic occlusion. Percutaneous management relies on thrombolysis with plasminogen activators, mechanical removal of thrombus and angioplasty of the stenotic lesion. Objectives: This report describes a phase I trial using Plasmin (Human) TAL 05-00018, a direct-acting fibrinolytic agent, to evaluate safety and, secondarily, to establish effective thrombolytic dosing. Patients/methods: Six cohorts of 5 patients with acute HD graft occlusion documented by angiography were treated with escalating dosages of plasmin (1, 2, 4, 8, 12, and 24 mg) infused over 30 minutes via criss-crossed pulse-spray catheters within the graft. The primary efficacy endpoint was >/=50% thrombolysis, as determined by comparison of pre- and 30-minute post-plasmin fistulograms. Results: Of 31 subjects who received study drug (safety population), 1 withdrew and 30 completed the trial (evaluable for efficacy). There was no significant change in plasma alpha-2 antiplasmin or fibrinogen concentration, major bleeding did not occur and there were no deaths. Serious adverse events in 4 patients were not related to study drug. There was a dose-response relationship for the primary efficacy endpoint, all 5 subjects receiving 24 mg achieving >75% lysis. Conclusions: This first phase I study of Plasmin (Human) TAL 05-00018, infused into thrombosed HD grafts, documents safety at dosages of 1 to 24 mg and an effective thrombolytic dosage of 24 mg. The results establish a foundation for further clinical study of catheter-based plasmin administration in thrombotic disorders.

The genomic matching technique has proven useful in MHC haplotyping in humans. We have adopted a similar approach in Australian cattle dogs and report that genotyping can be achieved with a single assay.