Oxaliplatin and 5-FU/folinic acid (modified FOLFOX6) with or without aflibercept in first-line treatment of patients with metastatic colorectal cancer: The AFFIRM study

Background: The combination of aflibercept with FOLFIRI has been shown to significantly prolong overall survival in patients with metastatic colorectal cancer (mCRC) after progression on oxaliplatin-based therapy. This trial evaluated the addition of aflibercept to oxaliplatin-based first-line treatment of patients with mCRC. Patients and methods: Patients with mCRC were randomized to receive first-line therapy with mFOLFOX6 plus aflibercept (4 mg/kg) or mFOLFOX6 alone. The primary end point of this phase II study was the progression-free survival (PFS) rate at 12 months in each arm. The analysis of efficacy between the arms was a pre-planned secondary analysis. Results: Of 236 randomized patients, 227 and 235 patients were evaluable for the primary efficacy analysis and safety, respectively. The probabilities of being progression-free at 12 months were 25.8% [95% confidence interval (CI) 17.2- 34.4] for the aflibercept/mFOLFOX6 arm and 21.2% (95% CI 12.2-30.3) for the mFOLFOX6 arm. The median PFS was 8.48 months (95% CI 7.89-9.92) for the aflibercept/mFOLFOX6 arm and 8.77 months (95% CI 7.62-9.27) for the mFOLFOX6 arm; the hazard ratio of aflibercept/mFOLFOX6 versus mFOLFOX6 was 1.00 (95% CI 0.74-1.36). The response rates were 49.1% (95% CI 39.7-58.6) and 45.9% (95% CI 36.4-55.7) for patients treated with and without aflibercept, respectively. The most frequent treatment-emergent grade 3/4 adverse events (AEs) excluding laboratory abnormalities reported for aflibercept/mFOLFOX6 versus mFOLFOX6 were neuropathy (16.8% versus 17.2%) and diarrhea (13.4% versus 5.2%). Neutropenia grade 3/4 occurred in 36.1% versus 29.3%. The most common vascular endothelial growth factor inhibition class-effect grade 3/4 AEs for aflibercept/mFOLFOX6 versus mFOLFOX6 were hypertension (35.3% versus 1.7%), proteinuria (9.2% versus 0%), deep vein thrombosis (5.9% versus 0.9%) and pulmonary embolism (5.9% versus 5.2%). Conclusion: No difference in PFS rate was observed between treatment groups. Adding aflibercept to first-line mFOLFOX6 did not increase efficacy but was associated with higher toxicity.