MebendazolePhase I Study of Mebendazole in Newly Diagnosed High-Grade Glioma Patients Receiving Temozolomide

Glioblastoma (GBM) is the most common and aggressive brain cancer, and despite significant advances in treatment the majority of patients die within two years of diagnosis. During routine animal studies we serendipitously observed that fenbendazole, a benzimidazole antihelminthic used for pinworms, prevented tumor engraftment. Subsequent in vitro and in vivo experiments with benzimidazoles identified mebendazole as the drug having the best results in preclinical testing 1. In GBM cell lines, mebendazole displayed cytotoxicity with IC50s ranging from 0.1-0.3 μM. Mebendazole disrupted microtubule formation in GBM cells and it's in vitro activity was correlated with reduced tubulin polymerization. In two orthotopic mouse glioma models, one syngeneic and one xenograft, mebendazole significantly extended average survival up to 63% compared to untreated controls 1. Mebendazole is an FDA approved antiparasitic agent with a well-established side effect and safety record and was effective in our animal models in dosing schedules that are documented as safe in humans. Therefore, mebendazole is a possible anti-cancer therapeutic with pre-clinical safety and efficacy and provides a promising opportunity for a clinical trial in patients with malignant gliomas. In addition, a recently published case report case report from the University of Michigan documented successful long term control in metastatic adrenocortical adenocarcinoma using mebendazole 2. Mebendazole was well tolerated at 200 mg/day and used as the sole treatment after the patient failed other chemotherapies.