A Randomized Phase II Open Label Study to Compare the Safety and Efficacy of Subcutaneous Dalteparin Versus Direct Oral Anticoagulants for Cancer-associated Venous Thromboembolism

This randomized II clinical trial will enrol patients with advanced upper gastrointestinal, hepatobiliary and pancreatic cancer who have venous thromboembolism (VTE), including pulmonary embolism and deep vein thrombosis. Patients will be randomized in a 1:1 ratio and stratified by performance status, type of cancer and medical centers. The enrolled patients will receive either subcutaneous dalteparin or DOAC(rivaroxaban, apixavan) according to randomization until the end of planned treatment schedules (six months), recurrence of VTE, clinical relevant bleeding, major bleeding, death or discontinuation of study treatment for any other reason (e.g. withdrawal of consent or discretion of the investigator). The primary end-point is the rate of clinical relevant bleeding event as defined as overt bleeding which was associated with medical intervention. In addition to time to clinical relevant bleeding event, time to event of major bleeding, total bleeding including minor event, time to recurrent VTE, overall bleeding rate and overall VTE recurrent rate will be analyzed to compare safety and efficacy of both anticoagulants. The final analysis will be conducted when the last enrolled patient has an event or has completed as least six months follow up in the study. Patients without bleeding and recurrent VTE events at data cut-off are censored at the last date the patient is known to be free of events. Planned interim analysis will be conducted in the intentions to treatment analysis set. The interim analysis for the randomized portion of the study will be performed when at least 40% of estimated bleeding events have been observed. The purpose of interim analysis is for early stopping of the study for safety. This study will use a Data Monitoring Committee.