Phase I/II study of everolimus combined with mFOLFOX-6 and bevacizumab for first-line treatment of metastatic colorectal cancer.

Background This phase I/II trial evaluated toxicity and antitumor activity of everolimus plus mFOLFOX6 + bevacizumab for first-line treatment of metastatic colorectal cancer (mCRC). Methods A phase I, modified 3 + 3 Fibonacci schema determined the maximum tolerated dose (MTD) of everolimus, followed by phase II dose expansion. The phase II primary objective was progression-free survival at 6 months (PFS-6 m). Results The everolimus MTD was 10 mg daily with mFOLFOX6 + bevacizumab based on safety from phase I (n = 22). Twenty-five patients were treated in the phase II at 10 mg everolimus daily. Frequent grade 3-4 adverse events were neutropenia (64%), leukopenia (28%) and hypokalemia (26%). Grade 2 stomatitis was observed in 62% of patients. Two dose-limiting toxicities were observed with one attributed to everolimus 10 mg daily (grade 3 diarrhea, hypokalemia, and anorexia) and grade 3 coronary vasospasm attributed to fluorouracil. The objective response rate was 53% and was higher (86%) in those with PTEN deficiency. PFS-6 m was 96% (95% CI 89-99.9%) at the MTD (n = 35). The everolimus recommended phase II dose of this regimen is 7.5 mg daily due to frequent stomatitis and dose reductions. Conclusions Everolimus plus mFOLFOX-6 + bevacizumab is tolerable and demonstrated preliminary efficacy for first-line mCRC. Further studies are warranted in PTEN deficiency.