Genistein combined with FOLFOX or FOLFOX-Bevacizumab for the treatment of metastatic colorectal cancer: phase I/II pilot study

Background Epidemiologic and preclinical data suggest isoflavones have anticancer activity in colorectal malignancy prevention and treatment. This is the first clinical trial assessing safety and tolerability of Genistein in combination with chemotherapy in metastatic colorectal cancer. Methods Patients who had histologically confirmed metastatic colorectal cancer and had not received previous treatment were eligible to enroll. Subjects were treated with FOLFOX or FOLFOX-Bevacizumab as per the investigator choice. Genistein was administered orally for 7 days every 2 weeks, beginning 4 days prior to chemotherapy and continuing through days 1-3 of infusional chemotherapy. Primary endpoint was safety and secondary endpoints included cycle 6 response rate, best overall response rate (BOR), and median progression-free survival (PFS). Results Thirteen patients received chemotherapy with Genistein in this trial. The most common adverse events related to Genistein alone were mild and included headaches, nausea, and hot flashes. One subject was observed to have grade 3 hypertension. No increase in chemotherapy-related adverse events was observed when Genistein was added. BOR and median PFS were 61.5% and 11.5 months, respectively. Conclusion We observed that adding Genistein to FOLFOX or FOLFOX-Bevacizumab was safe and tolerable. Efficacy results are notable and warrant verification in larger clinical trials.