Primary thromboprophylaxis in patients with malignancy and central venous catheters: TRIM-Line randomized controlled trial - Design and rationale.

Patients with cancer have an increased risk of venous thromboembolism (VTE). This risk is further elevated in those with a central venous catheter (CVC). Although previous studies have shown that prophylactic doses of direct oral anticoagulants (DOACs) are associated with a reduced risk of VTE in ambulatory cancer patients starting chemotherapy, which has led to new recommendations from international clinical guidelines to use DOACs as primary thromboprophylaxis, the same guidelines have not recommended primary thromboprophylaxis for those requiring CVC insertion. As such, the TRIM-Line trial will randomize 1828 patients with active cancer and a newly inserted CVC to rivaroxaban 10 mg daily versus placebo. The primary efficacy outcome is the first objectively confirmed symptomatic or incidental major VTE (proximal upper or lower extremity deep vein thrombosis and/or pulmonary embolism) within 90 days of randomization. The primary safety outcome is major bleeding, as defined by the International Society on Thrombosis and Haemostasis criteria, within 90 days. The key secondary outcomes include clinically relevant non-major bleeding, arterial thrombosis, and overall mortality. The study will provide high-quality evidence to address a key knowledge gap regarding the benefit and risks of thromboprophylaxis in patients with active cancer and an indwelling CVC (NCT05029063).