Background: Nearly half of patients with colorectal cancer develop liver metastases and only 20% are initially resectable. Surgical resection of liver metastases results in five-year survival rates of 24-48%. Perioperative FOLFOX therapy increases progression free survival. In advanced disease the addition of targeting therapies to chemotherapy results in an overall survival advantage. In this study the efficacy and safety of perioperative panitumumab and FOLFIRI therapy were investigated. Methods: Patients with previously untreated, wild-type RAS, potentially resectable colorectal cancer liver metastases were included. Chemotherapy consisted of irinotecan 180mg/m² intravenously over 120 minutes and fluorouracil bolus 400mg/m² intravenously, followed by a 46 h infusion of fluorouracil 2400mg/m² repeated every 2 weeks. Panitumumab was given as an intravenous dose of 6mg/kg every 2 weeks. Preoperative 4 cycles and postoperative 8 cycles were administered. Primary objectives were the evaluation of efficacy and safety. Results: We enrolled 36 patients in 7 centers in Austria. ITT-analyses included 35 patients. There were 28 men and 7 women, the median age was 66 years. 91.4% completed the planned 4 cycles of preoperative therapy and 82.9% underwent liver resection. R0 resection rate was 82.7%. 20 patients started postoperative chemotherapy and 12 patients completed the planned 8 cycles. Objective response rate after preoperative therapy was 65.7% with one radiological complete remission and 22 partial remissions. In 20% and 5.7% of patients stable disease and progressive disease were documented, respectively. Three patients discontinued preoperative treatment due to adverse events without response evaluation. The most common grade 3 adverse events were diarrhea (n = 4), rash (n = 3) and leukopenia (n = 3) during preoperative therapy. One patient died due to sepsis and one had a pulmonary embolism grade 4. After surgery two patients died due to hepatic failure and one patient had a suture related complication grade 3. Most common grade 3/4 adverse events during postoperative therapy were rash (n = 2), stroke (n = 1) and intestinal obstruction (n = 1). Conclusions: Panitumumab in combination with FOLFIRI as preoperative therapy for operable colorectal liver metastases in RAS wild-type patients results in a radiological objective response rate in 65.7% of patients with a manageable grade 3 diarrhea rate of 14.3%. Progression-free survival and overall survival are still monitored. Clinical trial information: 2012_000265-20.