490 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.