Direct Oral Anticoagulants (DOACs) Versus LMWH +/- Warfarin for VTE in Cancer

Venous blood clots affect nearly a million Americans each year. Venous clots in the legs are called deep venous thrombosis (DVT) and are dangerous because they travel to the lungs where they cause blockages known as pulmonary emboli (PE). DVT and PE are called venous thromboemboli (VTE). Cancer is a risk factor with nearly 200,000 VTEs in cancer patients each year. The purpose of VTE treatment is to prevent the initial clot from spreading and to prevent new clots from forming. This is accomplished by thinning the blood, or anticoagulation. Without anticoagulation, VTEs recur and are often fatal.

Recently, the FDA has approved 4 new Direct Oral AntiCoagulants (DOACs) for preventing VTE recurrence. Few cancer patients were included in the efficacy trials, and practice guidelines fall silent on whether switching to DOAC therapy is advisable. To fill this knowledge gap, the Alliance Foundation Trials LLC, a research network of academic and community practices across the US, is conducting a pragmatic randomized effectiveness trial.

The overarching objective of the study is to determine the effectiveness of LMWH/ warfarin vs. DOAC anticoagulation for preventing recurrent VTE in cancer patients. The investigators will conduct a trial of 811 cancer patients followed for 6 months. The intervention strategy is DOAC therapy with edoxaban, apixaban, rivaroxaban, or dabigatran. The comparator is LMWH alone or with warfarin. Within each arm, patients can choose the agent they prefer based on side effects, drug interactions, and practical issues such as co-pays. The trial compares these two strategies in terms of treatment: 1) benefits based on VTE recurrence; 2) harms based on bleeding rates; 3) burdens based on patients' reports of their experiences; and 4) mortality rates.

The investigators hypothesize that the benefits, harms and burdens of DOAC treatment will be non-inferior to, or better than, usual care with LMWH/ warfarin among cancer patients. The information gained will empower cancer patients and physicians to make more informed choices about anticoagulation strategies to manage VTE.