Summary
Background: Recombinant hirudin, a pure, specific antithrombin could be more effective than heparin in the treatment of deep vein thrombosis, but its short half-life requires constant intravenous infusion, whereas subcutaneous administration of recombinant hirudin can ensure stable and prolonged plasma levels. The aim of our study was to assess the pharmacokinetics, the results on the coagulation variables, and the safety of a recombinant hirudin (HBW 023) administered subcutaneously in patients suffering from deep vein thrombosis.
Methods: Recombinant hirudin (HBW 023) was administered subcutaneously to 10 patients with recent deep vein thrombosis, at a dose of 0.75 mg/kg of body weight twice daily for 5 days, after which standard heparin and acenocoumarol were introduced. Bilateral lower limb venography, and pulmonary angiography, and/or ventilation-perfusion lung scan were carried out on day 1 prior to recombinant hirudin injection and repeated on day 5. aPTT and recombinant hirudin plasma levels were serially assessed after the 1st and the 10th injections. Prothrombin fragments 1 + 2, thrombin-antithrombin III complexes, fibrin degradation products were collected on days 1 and 5.
Results: Clinical evolution was uneventful in all but one patient who had a probable recurrence of pulmonary embolism on day 4. No hemorrhagic complication, no untoward biological event was observed. On days 5, Mardcr score was unchanged or had decreased. Plasma levels of recombinant hirudin peaked in between 3 and 4 h following the injection. aPTT values paralleled, and were significantly correlated with plasma levels of recombinant hirudin on day 1 as well on day 5 (r = 0.903, r = 0.948 respectively). Fragment 1 + 2, and thrombin antithrombin complexes non-significantly decreased from day 1 to day 5.
Conclusions: Subcutaneous administration of recombinant hirudin ensures prolonged stable plasma levels of recombinant hirudin which results in efficient anticoagulation. A dose-ranging study conducted with subcutaneous recombinant hirudin in comparison to conventional heparin therapy may answer the question as to efficacy.
