Single-dose TB-402 or rivaroxaban for the prevention of venous thromboembolism after total hip replacement

TB-402 is a long-acting monoclonal antibody that partially inhibits factor VIII. A single administration of TB-402 was effective and well-tolerated for the prevention of venous thromboembolism (VTE) after total knee replacement. In this study, the efficacy and safety of a single administration of TB-402 for the extended prophylaxis of VTE after total hip replacement (THR) was investigated. This was a phase II, randomised, active-controlled, double-blind study that included patients undergoing elective THR surgery. Patients were randomised to TB-402 25 mg or TB-402 50 mg, administered as a single intravenous administration 2-4 hours postoperatively, or to rivaroxaban 10 mg once daily for 35 days. The primary efficacy outcome was total VTE defined as symptomatic VTE and asymptomatic deep-vein thrombosis (DVT) detected by bilateral venography at day 35. The principal safety outcome was the incidence of major bleeding and clinically relevant non-major bleeding until day 35. Total VTE was similar in all groups: 5.3% (95%CI 2.9-9.6), 5.2% (95%CI 2.8-9.3) and 4.7% (95%CI 2.5-8.7) for TB-402 25 mg, TB-402 50 mg and rivaroxaban, respectively. All were asymptomatic DVTs. Major or clinically relevant non-major bleedings were observed in 5.8% (95%CI 3.3-9.9), 7.2% (95%CI 4.4-11.6) and 1.4% (95%CI 0.5-4.2) for TB-402 25 mg, TB-402 50 mg and rivaroxaban, respectively. In conclusion, TB-402, administered as a single postoperative dose, had a similar efficacy compared to rivaroxaban for the prevention of VTE after THR. The incidence of major and clinically relevant non-major bleeding was higher in the TB-402 groups than in the rivaroxaban group.