Background: Everolimus (E), an oral rapamycin analogue, is a potent mTOR inhibitor. Combined inhibition of VEGF and mTOR pathways may increase anti-angiogenic and anti-tumor activity. We evaluated E in combination with capecitabine (C), oxaliplatin (O), and bevacizumab (B) in a phase I dose escalation study. Methods: Eligible patients (pts) had advanced solid tumors, adequate organ function and no increased risk for class-related toxicities. B and O were given intravenously; C and E were orally administered. Cycle length was 21 days. Doses for level 1: C 850 mg/m² on days 1-14; O 130 mg/m² on day one; B 7.5 mg/kg on day one; and E 5 mg three times a week. Doses for level -1: C 680 mg/m², O100mg/m². An intermediate dose level (-1b) of E escalated to 5 mg five times weekly was added to maximize dose intensity. Dose limiting toxicity (DLT) was assessed in cycle 1. Concomitant administration of CYP3A4 substrates, inhibitors or inducers was prohibited. Results: Dose escalation is complete with 27 pts evaluable for toxicity and 24 evaluable for efficacy. Two DLTs (grade 2 intolerable fatigue, anorexia, vomiting and grade 3 diarrhea) were observed in 6 pts in cohort 1. No DLTs were observed in cohort -1; one DLT (rectovaginal fistula) was observed in the -1b cohort. Possible grade ≥3 treatment-related adverse events any time on study (n=1 except as indicated) included diarrhea (n=2), intestinal perforation/fistula, rectovaginal fistula, hypertriglyceridemia (n=3), hyperglycemia, hypoalbuminemia, hyponatremia, peripheral neuropathy, neutropenia (n=2), lymphopenia, thrombocytopenia, hypertension (n=3), deep vein thrombosis, and arterial thrombosis. Adverse events were consistent with known class-related toxicities. For efficacy, 10 pts had a partial response (PR); 10 had stable disease as best response. Of 13 pts with chemorefractory metastatic colorectal cancer (mCRC), 5 had a PR. Of 8 pts with chemonaive mCRC, 5 had a PR. Conclusions: E in combination with full dose C, O and B was associated with unacceptable toxicity, primarily GI toxicity. E at 5mg five times weekly, C at 680 mg/m² on days 1-14, O at 100 mg/m² and B at 7.5 mg/kg on day one appears well tolerated. Activity was noted in chemorefractory and chemonaive mCRC patients.