A dose-finding clinical trial of staphylokinase SY162 in patients with long-term venous access catheter thrombotic occlusion.

Background: We investigated the safety and efficacy of several dosing regimens of catheter-directed staphylokinase (SY162) bolus administration for the treatment of long-term venous access catheter occlusion.

Methods: This open-label, ascending dose study enrolled 24 subjects. Three doses of SY162 were evaluated in three cohorts (0.15 mg, 0.3 mg and 0.45 mg) with eight subjects each. Catheter function was evaluated 30 min after the first bolus administration. In case of incomplete catheter function restoration, a second bolus was administered with reassessment of catheter function 30 min thereafter. Cathetergram was repeated to assess thrombus resolution.

Results: Complete restoration of catheter withdrawal function was observed in 2 (25%), 1 (13%) and 7 (88%) subjects after the first bolus in the first, second and third cohort respectively and in 4 (50%), 7 (88%) and 7 (88%) patients after the second administration of SY162. There were no bleeding complications nor other adverse events related to SY162.

Conclusions: The doses tested in this trial were well tolerated and safe. A dose-response effect within the dose range tested was observed. A 2 ml bolus injection of 0.45 mg SY162 resulted in optimal efficacy after 30 min.