Combining anti-VEGFR and anti-EGFR antibodies: Randomized phase II study of irinotecan and cetuximab with/without ramucirumab in second-line colorectal cancer:(ECOG-ACRIN E7208).

INTRODUCTION:Early studies showed promise of combined anti-EGFR plus anti-VEGF antibodies for advanced colorectal cancer (CRC), yet this was later rejected as toxic and ineffective in studies not selected for RAS status. We studied advanced KRAS wild-type CRC, as second-line treatment, using irinotecan-cetuximab (IC) with or without the anti-VEGFR antibody, ramucirumab (ICR). METHODS:Patients with one prior regimen including fluoropyrimidine, oxaliplatin and bevacizumab, with KRAS wild-type tumors, were stratified by ECOG PS, time since last chemotherapy and progression on oxaliplatin, to IC (180 and 500 mg/2 q2w), vs modified ICR (mICR) (150 and 400 mg/m2 plus 6 mg/kg respectively). 102 patients were compared for progression-free survival (PFS) as primary endpoint (85% power for 70% improvement in median PFS from 4.5 to 7.65 months). RESULTS:Of the 102 enrolled, 44 treated with IC and 45 with mICR were evaluable. Median PFS was 6.0 vs 9.2 months respectively (HR 0.75, p = .07, significant by study design for p < .128). Response rate was 23% vs 36% (p = .27) and disease-control rate (DCR) was 52% vs 73% (p = .05). Grade ≥3 toxicity was not equivalent. Overall survival was not significantly different at ∼19 months. CONCLUSION:Previous phase 3 trials without RAS genotyping, rejected combining anti-EGFR and anti-VEGF drugs. In this randomized multi-center phase 2 study for KRAS wild type CRC (all previously bevacizumab-treated) the addition of ramucirumab, to irinotecan and cetuximab improved PFS and DCR, showing the combination is feasible and effective here. Further phase 3 trials with appropriate patient-selection are required. (NCT01079780).