Abstract
PURPOSE: Colorectal cancer is the second leading cause of cancer-related mortality in the United States. Chemotherapies based on 5-fluorouracil (5-FU), when combined with targeted agents, remain the standard of care for patients with metastatic or locally advanced disease. New treatment strategies are needed for patients with metastatic colorectal cancer with microsatellite stable disease. Preclinical studies have shown that riluzole, an oral medicine for amyotrophic lateral sclerosis, inhibits glutamate release and synergizes with 5-fluorouracil to reduce cell viability in colorectal cancer cell lines. PATIENTS AND METHODS: In this single-arm, phase I trial of riluzole in combination with mFOLFOX6/bevacizumab for patients with metastatic colorectal cancer, the riluzole dose started at 50 mg twice daily, escalating to 100 mg twice daily or de-escalating to 50 mg once daily. Patients received riluzole for 16 weeks in combination with mFOLFOX6/bevacizumab for eight cycles. Patients then either continued mFOLFOX6/bevacizumab or switched therapies. RESULTS: Twelve of the 14 patients enrolled were evaluable. All patients had previously received FOLFOX, and five patients (41.7%) showed disease resistance to it. Two patients obtained partial responses, nine had stable disease, and one had progressive disease. The objective response rate was 16.7%, and the disease control rate was 91.7%. The median duration of response was 4.9 months (95% confidence interval, 1.6-9.8). Median progression-free survival and overall survival were 4.89 and 12.98 months, respectively. CONCLUSIONS: Our study showed that riluzole plus mFOLFOX6/bevacizumab is well tolerated in patients with metastatic colorectal cancer and may have clinical activity in patients whose disease is resistant to FOLFOX.