title: PO-41 - Rivaroxaban is effective therapy for high risk cancer patients with venous thromboembolic disease.
abstract: BACKGROUND
  The standard of care for cancer associated venous thromboembolism (VTE) is generally accepted to be at least six months of therapeutic doses of low molecular weight heparin (LMWH). After six months it is recommended that therapy be continued but no studies have evaluated treatment in this period. Rivaroxaban is a potentially effective therapy given cancer patients were enrolled in the EINSTEIN trial with acceptable safety and efficacy but details on these patients is lacking.
  
  
  OBJECTIVE
  To determine the safety and efficacy of rivaroxaban for the treatment of cancer associated VTE.
  
  
  METHODS
  We performed a retrospective chart review of all cancer patients seen in our thrombosis program and enrolled patients seen between January 2012 and April 2015. Complete patient identification was accomplished through our hospital data warehouse. We recorded all relevant demographics. Initial diagnoses were all confirmed with objective imaging tests according to standard definitions. Major bleeds, using the ISTH definition, and recurrent VTE events were adjudicated by at least two observers.
  
  
  RESULTS
  237 active cancer patients received treatment with rivaroxaban; 65 (27%) were initiated on rivaroxaban, 30 (12.6%) started between day 8 and 2 months, 75 (32%) started therapy between day 8 and the 6 month point and 97 (41%) started therapy at 6 months or beyond. 26 patients were put on rivaroxaban after failing LMWH. The average duration of rivaroxaban therapy was 297 days; The average age of patients was 61 (SD±13); 41% of patients were male, 59% were female. 47% of patients had metastatic cancer. Of the 65 patients who were initiated on rivaroxaban 24 (37%) had metastatic cancer. Overall 3.8% of patients recurred while on rivaroxaban therapy with no deaths due to PE, and 3 patients had major hemorrhage with 2 deaths. Of the 9 patients who recurred on rivaroxaban, 3 of them were initiated on rivaroxaban, 3 of them were started 8 days-6 months, and 3 of them started after 6 months. The median number of days from initiation of rivaroxaban to VTE recurrence was 113. 26 patients received rivaroxaban after a recurrent event on therapeutic doses of LMWH, none recurred. Of the 65 patients who were initiated on rivaroxaban 3 recurred and of the 97 patients who were started on rivaroxaban after 6 months three recurred 0.580). All patients were treated on an outpatient basis.
  
  
  CONCLUSIONS
  Recurrence and major bleeding events on rivaroxaban were low despite the fact almost half the patients had metastatic disease. Rivaroxaban can be considered acceptable therapy for the treatment of cancer associated with venous thromboembolic disease.
authors.affiliation: Department of Medicine, University of Ottawa, Ottawa Hospital Research Institute, Canada.
authors.forename: P S
authors.initials: PS
authors.lastname: Wells
authors.affiliation: Department of Medicine, University of Ottawa, Ottawa Hospital Research Institute, Canada.
authors.forename: I A
authors.initials: IA
authors.lastname: Theberge
authors.affiliation: Department of Medicine, University of Ottawa, Ottawa Hospital Research Institute, Canada.
authors.forename: J C
authors.initials: JC
authors.lastname: Bowdridge
authors.affiliation: Department of Medicine, University of Ottawa, Ottawa Hospital Research Institute, Canada.
authors.forename: M A
authors.initials: MA
authors.lastname: Forgie
authors.affiliation: Department of Medicine, University of Ottawa, Ottawa Hospital Research Institute, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Carrier