535P - Safety and effectiveness of oral rivaroxaban for the treatment of venous thromboembolism in cancer patients

Abstract

Background: Cancer patients are at an increased risk of venous thromboembolism (VTE), even in the absence of traditional VTE risk factors. Cancer patients account for 20% of the patients with VTE. Although direct oral anticoagulants (DOACs) are as safe and effective as conventional anticoagulation (heparin followed by vitamin K antagonists) for treating VTE, the use of DOACs for cancer patients is less common. DOACs do not require monitoring and have little drug interaction with other drugs. We aimed to assess the safety and effectiveness of oral rivaroxaban, a DOAC, in patients with a history of intravenous (IV) antineoplastic drug administration in our hospital. Methods: We retrospectively extracted data of patients prescribed rivaroxaban and IV antineoplastic drugs from July 2011 to March 2017 at Kobe city medical center general hospital, and investigated adverse events during the administration period with the electronic medical record. Results: Of 76 patients, 39 had VTE, 37 had atrial fibrillation (Af), 2 had other diseases, and 2 had both VTE and Af. Of 39 patients with VTE, 38 were active cancer patients (11 had pulmonary embolism: PE). The characteristics of the 38 active cancer patients with VTE were as follows: median age (range), 66.5 (45-79); male/female, 17/21; and creatinine clearance [mean±SD], 85.7±28.1 mL/min. The most common primary site in the 38 patients was the colon (7), stomach (6), and ovary (6). The starting dose was 30 mg/day (13), 20 mg/day (1), 15 mg/day (21), 10 mg/day (2), and unknown (1). Nine patients discontinued rivaroxaban due to hematuria (2), bleeding from the uterus (1), epigastric discomfort (1), patient’s request (2), and unknown reasons (3). Two patients required dose reduction due to deterioration of renal function or significant weight loss. With a median follow-up of 5.9 months (range, 4 days-13.9 months), bleeding events was seen in 17 patients, of which 3 (8%) were clinically relevant; however, no severe bleeding was observed. Thrombosis reduced or disappeared in 29 of 30 evaluable patients (97%). PE were disappeared in 9 of 11 patients (82%). Conclusions: Using oral rivaroxaban for cancer-associated VTE is as safe and effective as conventional anticoagulation therapy. Legal entity responsible for the study: Kobe City Medical Center General Hospital Funding: None Disclosure: All authors have declared no conflicts of interest.