SHR-2004, a Humanized Monoclonal Antibody Targeting Factor XI, for Preventing Venous Thromboembolism After Ovarian Cancer Surgery: A Randomized, Active-Controlled Phase 2 Study.

This multicenter, randomized, open-label, exploratory Phase 2 trial assessed SHR-2004, an anti-FXI antibody, for venous thromboembolism (VTE) prevention in patients undergoing ovarian cancer surgery-a population at particularly high thrombotic risk conducted at 25 sites in China. Patients with newly diagnosed Stage III-IV or recurrent ovarian cancer scheduled for surgery were randomly assigned (1:1) to receive subcutaneous SHR-2004 (180 mg on Day 1 and 120 mg on Day 15) or enoxaparin-rivaroxaban (subcutaneous enoxaparin 40 mg once daily during hospitalization, followed by oral rivaroxaban 10 mg once daily after discharge until Day 28). The primary efficacy outcome was the composite of VTE events within 28 days. The primary safety outcome was major bleeding (MB) or clinically relevant nonmajor bleeding (CRNMB) from first dose to 28 days. Between February 19, 2024 and September 17, 2024, 198 patients received assigned treatment (90 with SHR-2004, 108 with enoxaparin-rivaroxaban) and were included in the safety analysis. Among 181 patients who completed protocol-mandated ultrasonography, VTE occurred in 11 (12.6%) patients in the SHR-2004 group and 19 (20.2%) in the enoxaparin-rivaroxaban group (difference -8.4%, 95% CI -19.9 to 3.1) by Day 28. MB/CRNMB rates were similar between groups (SHR-2004: 2/90 [2.2%]; enoxaparin-rivaroxaban: 2/108 [1.9%]). In this study, SHR-2004 showed comparable efficacy to enoxaparin-rivaroxaban for preventing postoperative VTE in patients undergoing ovarian cancer surgery, with a similar low risk of MB or CRNMB. The twice-monthly dosing schedule offers a potential advantage over daily anticoagulation, supporting further investigation in adequately powered Phase 3 trials. Trial Registration: ClinicalTrials.gov identifier: NCT06220123.