Rivaroxaban does not affect growth of human pancreatic tumors in mice

BACKGROUND: Some clinical studies have shown that low-molecular-weight heparins (LMWHs) prolong the survival of cancer patients. In addition, various anticoagulants have been shown to reduce growth of tumors in mice. However, there are no studies on the effect of the factor Xa inhibitor rivaroxaban on growth of human pancreatic tumors in nude mice. OBJECTIVES: To test the hypothesis that the factor Xa inhibitor rivaroxaban reduces the growth of tissue factor (TF)-positive pancreatic tumors but not TF-negative pancreatic tumors in mice. METHODS: The TF-positive human pancreatic cancer cell line BxPc-3 and the TF-negative human pancreatic cancer cell line MIA PaCa-2 were injected subcutaneously into nude mice and tumors grown to a mean volume of ~100 mm(3) . Mice were then divided into two groups. One group was fed chow containing rivaroxaban (0.5 g/kg chow) whereas the other group was fed chow without rivaroxaban. RESULTS: Rivaroxaban significantly prolonged prothrombin time in tumor-bearing mice. Rivaroxaban did not affect cell proliferation or growth of either BxPc-3 or MIA PaCa-2 tumors grown subcutaneously in nude mice. CONCLUSION: Our results indicate that inhibition of factor Xa with rivaroxaban does not affect the growth of two human pancreatic tumors in nude mice.