4112 Background: Axitinib is an oral, potent and selective inhibitor of VEGF receptors 1, 2, and 3 that is being assessed in a broad range of tumors. This phase I portion of the study evaluated the safety and pharmacokinetics (PK) of axitinib in combination with BV and FOLFOX (oxaliplatin/5-fluorouracil [5-FU]/leucovorin) in pts with previously treated gastrointestinal and solid tumors. Methods: Pts in cohort 1 received BV 1 mg/kg, oxaliplatin 85 mg/m2, leucovorin 400 mg/m2, 5-FU 400 mg/m2 bolus then 2,400 mg/m2 by 46–48 h infusion, and axitinib at a starting dose of 5 mg PO BID. BV and FOLFOX were administered once every 2 weeks. Following demonstration of tolerability to BV 1 mg/kg in cohort 1, BV was escalated to doses of 2 mg/kg and 5 mg/kg in cohorts 2 and 3 respectively. Patients were evaluated for potential PK interactions between BV, FOLFOX, and axitinib. Safety and tumor response were also assessed. Results: Among pts enrolled in cohorts 1, 2, and 3 (n=15), 2 patients (13%) showed a partial response and 9 patients (60%) exhibited stable disease. The most frequently reported, treatment-emergent grade 3–5 adverse events were neutropenia (n=3), hypertension (n=3), and dyspnea (n=2). PK parameters and plasma profiles of BV, oxaliplatin, and 5-FU were similar in the presence or absence of axitinib, with mean (%CV) AUCinf for platinum clearance from ultrafiltrate of 7,155 ng.h/mL (74%) and 7,702 ng.h/mL (72%), respectively (n=14). Axitinib PK profiles were similar in the presence or absence of BV/FOLFOX. Conclusions: PK data indicate no evidence of an interaction between axitinib and BV/FOLFOX. Axitinib 5 mg BID in combination with BV 1 mg/kg or 2 mg/kg and FOLFOX was well tolerated. Tolerability data for combination treatment with the 5 mg BV dose await completion of patient enrollment into cohort 3. A 3-arm, randomized phase II study of axitinib/FOLFOX vs BV/FOLFOX vs axitinib/BV/FOLFOX in pts with metastatic colorectal cancer has been initiated. Author Disclosure Employment or Leadership Consultant or Advisory Role Stock Ownership Honoraria Research Expert Testimony Other Remuneration Pfizer Pfizer