An analysis of the safety and efficacy of rivaroxaban (Riv) and low molecular weight heparin (LMWH) in gastrointestinal cancer-associated venous thromboembolism (GICA-VTE).

Abstract

374 Background: CAVTE has a significant morbidity and mortality burden, with higher incidence and bleeding complications of anticoagulation (AC) in GICA. Current guidelines prefer LMWH, and recently added Riv, as an alternative standard after the SELECT-D trial (S-D). There is a paucity of data comparing the safety and efficacy of other DOACs in pts with GICA. We indirectly compared the safety and efficacy of Riv vs LMWH of our pts with active GICA-VTE at the University of Arizona Cancer Center (UACC) to the S-D GI-population. Methods: Pts with biopsy proven GICA, symptomatic or incidental VTE, and 6 months or more treatment with Riv or LMWH at UACC from 11/2013 - 12/2017 were retrospectively reviewed. S-D GICA data was extracted. Primary efficacy outcome was recurrent deep vein thrombosis (DVT), nonfatal pulmonary embolism (PE), or fatal PE. Safety outcomes for major bleeding (MB) include Hg drop ≥ 2 g/dL, transfusion of ≥ 2 units PRBC, bleeding in critical site, or bleeding contributing to death. Fisher exact test was used for p-value < 0.05. Results: Our review included pts on LMWH (n = 40), and Riv (n = 37) balanced population to the S-D trial. Recurrent VTE at 6mo was noted in 7.5% and 2.7% of pts, compared to S-D trial 11% and 4%, for LMWH and Riv respectively. MB at 6mo was 5% and 21.6% [p < 0.04] of pts, compared to S-D trial 5.8% and 8.7%, for LMWH and Riv, respectively. There was a non-significant difference [p > 0.07] between Riv and LMWH efficacy and safety beyond 6mo of AC. Conclusions: VTE secondary prophylaxis in GICA pts is complicated by high rates of recurrence and bleeding risk, DOACs provide another AC option. The most recent systemic review that included the two published DOACs RCTs for CAVTE [Hokusai and SELECT-D 2018], showed a higher incidence at 6-month of MB compared to LMWH RR: 1.74 (95% CI: 1.05–2.88) [Ang Li 2018], mainly driven by GICA. Our retrospective study showed a non-significant improved efficacy outcome although worse safety profile with Riv versus LMWH in GICA pts, by indirect comparison. Future RCTs with multi-center participation, particularly focused on GICA, can further provide information to guide safe and effective AC selection.