Thrombomodulin alfa prevents oxaliplatin-induced neuropathic symptoms through activation of thrombin-activatable fibrinolysis inhibitor and protein C without affecting anti-tumor activity

Abstract

Oxaliplatin, a platinum-based chemotherapeutic agent, is widely used to treat colorectal cancer, but it induces peripheral neuropathy as a serious dose-limiting side effect. Recently, thrombomodulin alfa, a recombinant human soluble thrombomodulin, was reported to prevent oxaliplatin-induced peripheral neuropathy in a clinical phase 2 study. Here we conducted preclinical pharmacology studies. Rats were given oxaliplatin (6 mg/kg) intravenously to induce mechanical hyperalgesia associated with peripheral neuropathy. Single intravenous administration of thrombomodulin alfa (0.1, 0.3, 1 mg/kg) dose dependently prevented the development of oxaliplatin-induced mechanical hyperalgesia, with no sex difference in the efficacy. The preventative effect of thrombomodulin alfa on mechanical hyperalgesia was attenuated by antithrombin or carboxypeptidase inhibitor. In addition, carboxypeptidase B, a homolog of activated thrombin-activatable fibrinolysis inhibitor (TAFI) and human-derived activated protein C, prevented mechanical hyperalgesia, whereas antithrombin or other anti-coagulants did not. These results suggest that thrombomodulin alfa prevents sensory symptoms of oxaliplatin-induced peripheral neuropathy through the activation of TAFI and protein C by modulating thrombin activity, but the effects are independent of an anticoagulant effect. On the other hand, thrombomodulin alfa did not affect the anti-cancer activity of oxaliplatin on human colon cancer cell lines or mice transplanted with HCT116 cells. These results indicate that thrombomodulin alfa prevents sensory symptoms of oxaliplatin-induced peripheral neuropathy without affecting the anti-tumor activity of oxaliplatin. Therefore, thrombomodulin alfa is a promising drug to prevent the symptoms of oxaliplatin-induced peripheral neuropathy.