Rivaroxaban thromboprophylaxis for gastric/gastroesophageal junction tumors versus other tumors: A post hoc analysis of the randomized CASSINI trial

Prophylactic anticoagulation with rivaroxaban significantly reduced the risk of cancer‐associated thrombosis during the intervention period in the CASSINI trial. Direct oral anticoagulants may increase the risk of gastrointestinal (GI) tract bleeding in patients with an in situ GI tract cancer or lesion. This post hoc analysis characterized the efficacy and safety of rivaroxaban in patients with and without gastric/gastroesophageal junction (G/GEJ) tumors. Primary and secondary efficacy end points and adjudicated bleeding events, including bleeding sites, were analyzed for the intent‐to‐treat population by cancer type (G/GEJ vs non‐G/GEJ) for the 180‐day observation period. In patients with G/GEJ tumors, the rates for the primary efficacy end point were 3.4% for rivaroxaban versus 6.9% for placebo (hazard ratio [HR], 0.45; 95% confidence interval [CI], 0.11‐1.80). In patients with non‐G/GEJ tumors, the rivaroxaban group had a lower risk of the primary end point (6.6% vs 9.3%; HR, 0.70; 95% CI, 0.40–1.21). Rates of major bleeding in patients with G/GEJ tumors were 4.6% (4/88) versus 1.2% (1/85) for rivaroxaban and placebo; rates in patients with non‐G/GEJ tumors were 1.3% (4/317) versus 0.9% (3/319), respectively. Excluding patients with G/GEJ tumors resulted in a definable population of cancer patients who achieved an improved benefit‐risk balance from rivaroxaban prophylaxis.