A phase I study of axitinib (AG-013736) in combination with bevacizumab plus chemotherapy or chemotherapy alone in patients with metastatic colorectal cancer and other solid tumors

Background: Axitinib and bevacizumab are targeted therapies against the vascular endothelial growth factor pathway. Methods: Patients with previously treated solid tumors received axitinib (starting dose 5 mg twice daily) combined with FOLFOX plus bevacizumab (1, 2, or 5 mg/kg, cohorts 1-3, respectively), FOLFIRI (cohort 4), or FOLFOX (cohort 5). Safety and pharmacokinetics were assessed. Results: Thirty patients were enrolled (n = 16, 8, and 6 for cohorts 1-3, 4, and 5, respectively). Plasma concentrations and pharmacokinetic (PK) parameters were similar when drugs were administered alone and in various combinations. Most treatment-emergent adverse events (AEs) were mild to moderate and clinically manageable (most common: nausea, fatigue, diarrhea, anorexia, hypertension). Two of the four patients receiving axitinib with FOLFOX plus 5 mg/kg bevacizumab experienced dose-limiting toxicity (DLT) of inability to resume treatment for 14 days following treatment interruption (associated AE: hypertension); the maximum tolerated dose of bevacizumab in this combination was 2 mg/kg. No DLTs occurred with axitinib plus FOLFIRI or FOLFOX. Ten patients had RECIST-confirmed partial tumor responses (objective response rate: 33.3%). Conclusion: Axitinib is well tolerated in combination with FOLFOX, FOLFIRI, or FOLFOX plus 2 mg/kg bevacizumab. PK interactions appear to be absent.