Phase I clinical trial to determine maximum tolerated dose of oral albendazole in patients with advanced cancer

Albendazole is a potential anticancer agent that is currently under development for the treatment of cancer. We carried out a dose-finding phase I study of oral albendazole in patients with advanced malignancies. Thirty-six patients with refractory solid tumors were enrolled. Albendazole was given orally on a day 1-14 of a 3 weekly cycle, starting at 400 mg BD with dose escalation until 1,200 mg BD. Serial blood samples were collected up to 96 h and also on day 8 of cycles 1 and 4. The maximum tolerated dose was 2,400 mg per day (1,200 BD). Myelosuppression was the main dose limiting toxicity. Fatigue and mild gastrointestinal upset were the other major adverse effects. 4 out of 24 assessable patients (16%) had a tumor marker response with a fall of at least 50% from baseline values and another patient had a prolonged period of stable marker response. A decline in plasma vascular endothelial growth factor levels was observed. Albendazole was well tolerated on the schedule tested in this trial. The results of this study suggest that the recommended dose for further study is 1,200 mg twice daily for 14 days in a 21-day cycle.