Inhibition of Soluble Epoxide Hydrolase Prevents Docetaxel-Induced Painful Peripheral Neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) is a painful condition recalcitrant to current available therapies. CIPN pain can be severe and dose-limiting or dose-reducing for life-extending chemotherapeutics and, to date, there is no treatment to alter the progression of CIPN. For these experiments we used docetaxel, a first-line therapy for metastatic prostate cancer in humans and investigated the soluble epoxide hydrolase inhibitor EC5026 for its analgesic efficacy against this CIPN pain. Male SD rats (n = 10/group) were pretreated with 1 mg/kg EC5026 in formulated drinking water or vehicle for one week prior to docetaxel injections. The rats continued the formulated drinking water during three once-a-week docetaxel 10 mg/kg i.p. injections and were maintained on treatment until the end of week 5 when all groups were transitioned to normal drinking water. Nociceptive testing occurred throughout the entire experiment including after transitioning to normal drinking water. EC5026 increased mechanical withdrawal thresholds and latencies on the cold plate compared to docetaxel-treated controls. There were no motor effects of the compound, and the formulated drinking water provided favorable exposure. These results demonstrated that EC5026 administered prophylactically was both analgesic and able to limit the severity of mechanical and cold sensitivities in the docetaxel CIPN rat model.