Panitumumab-based Maintenance in Patients With RAS Wild-type, Metastatic Colorectal Cancer (Valentino)

Open label, randomized, multicenter, phase II study to compare the efficacy, in terms of non-inferiority of progression-free survival (PFS), of maintenance with panitumumab alone (arm B) as compared to panitumumab with 5-fluorouracil (5-FU) and leucovorin (LV) (arm A) following induction treatment with 5-fluorouracil + leucovorin+oxaliplatin (FOLFOX-4) and panitumumab in patients with RAS wild-type, metastatic colorectal cancer. The study involves an induction phase with panitumumab as 1 hour intravenous infusion at the dosage of 6 mg/kg, given every two weeks, plus FOLFOX-4 chemotherapy as standard guidelines. Before start of FOLFOX-4 plus panitumumab, at the time of enrollment, patients will be immediately randomized electronically 1:1 to one of the two maintenance arms. Induction treatment with FOLFOX-4 plus panitumumab will continue until progressive disease, unacceptable toxicity or informed consent withdrawal, or for up to 8 cycles. At the end of induction treatment, in presence of complete or partial response, or stable disease, non-progressing patients will be allocated to one of the two pre-assigned maintenance arms: A) 5-FU/LV (De Gramont regimen) plus panitumumab given at 6 mg/Kg every two weeks until progressive disease, unacceptable toxicity or informed consent withdrawal B) Panitumumab alone given at 6 mg/Kg every two weeks until progressive disease, unacceptable toxicity or informed consent withdrawal Imaging studies (thorax and abdominal CT or MRI scan) will be performed at baseline (4 weeks prior enrollment) and every 8 weeks (4 cycles) during treatment.